Reactive polyamide imide oligomers, methods, and articles

Abstract

The invention relates to reactive polyamideimide oligomers, methods, and articles. The reactive ammonium carboxylic acid salts, polyamide amic acid oligomers and polyamide imide oligomers are made from at least one aromatic diamine, at least one aromatic di-, tri-or tetra-functional carboxylic acid or functional equivalents thereof, and at least one crosslinkable monomer or crosslinkable end-capping agent. The crosslinkable monomer or crosslinkable end-capping agent is reactive with at least one aromatic diamine or at least one di-, tri-or tetra-functional aromatic carboxylic acid or functional equivalents thereof, and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive polyamideimide oligomer. The number average molecular weight (Mn) of the reactive polyamide amic acid and polyamide-imide oligomer is from about 1000 to about 10000 g / mol as calculated using the Carothers equation. Reactive ammonium carboxylates, polyamidoamic acid oligomers, and polyamideimide oligomers may be used in a variety of functional materials, methods of manufacture, and articles.

Description

[0001] This application is a divisional application of the invention application with patent application number 202080077490.9, application date November 6, 2020, and invention title "Reactive Polyamideimide Oligomers, Methods, and Articles". Technical Field

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 932,892, filed November 8, 2019, and U.S. Provisional Application No. 63 / 075,610, filed September 8, 2020, the disclosures of which are incorporated herein by reference in their entireties. Background Art

[0003] Fully aromatic polyamideimide (PAI) is a high-performance polymer having alternating cyclic imide and amide bonds in the polymer backbone and was first commercialized in the early 1970s. High molecular weight PAI has excellent high-temperature strength, low-temperature toughness, and impact strength, as well as excellent chemical resistance and dimensional stability. High molecular weight PAI can have unimidized amic acid groups in the polymer backbone. The amic acid groups impart some flexibility to the polymer backbone, which makes PAI somewhat melt processable, but not easily. However, there are still several challenges associated with the melt processing of high molecular weight PAI. The melt viscosity is highly sensitive to temperature and shear rate, and PAI has a narrow processing window with processing temperatures required above 600°F (316°C). The amic acid is thermally converted to imide by cyclodehydration, and the conversion of the amic acid groups to cyclic imide groups results in a rapid increase in the rigidity of the polymer backbone and thus a rapid increase in the melt viscosity. If this occurs during extrusion, there is a risk that the polymer melt may solidify in the extruder. Due to the presence of unimidized amic acid groups, PAI is highly sensitive to moisture and must be thoroughly dried before melt processing and kept dry during melt processing to prevent degradation of the molecular weight and thermo-mechanical properties. In addition, imidization and removal of the imidization water may be required at 500°F (260°C) for 20 days or longer to obtain optimal properties. These difficulties limit the use of high molecular weight PAI to manufacture simple stock shapes such as rods, plates, tubes, and other profiles. These profiles can then be machined into parts that cannot be achieved by injection molding, for example, by turning, drilling, and milling steps.

[0004] Due to the processing limitations of high molecular weight PAI, injection molding grades with lower viscosities have been developed. These grades can be used to produce injection molded, filled and unfilled parts as well as profiles, but with great difficulty. The injection molding grades are considered to be mixtures of amine-terminated low molecular weight (oligomeric) polyamides and dianhydride chain extenders (such as pyromellitic dianhydride (PMDA)) to build up the molecular weight in-situ. The oligomeric nature of the polyamide reduces the melt viscosity, which aids the melt processing step, and the amine-terminated polyamide oligomers react with the dianhydride to form a high molecular weight polyamide amic acid intermediate through chain extension. After processing, the resulting parts and profiles require post-curing. In post-curing, the amic acid groups cyclize and dehydrate to form PAI. A major drawback of this route to PAI is the need to remove a large amount of water from the final parts. This water has two sources: i) physically adsorbed water associated with the hygroscopic residual amic acid moieties in the chain-extended PAI; ii) water generated in the cyclization dehydration step. Removing water from parts and profiles is a time-consuming process that requires a programmed heating schedule of several days to weeks, depending on the thickness of the part and its end use. There is a need in the art for fully aromatic PAI that does not require extended thermal post-curing and time-consuming water removal steps.

[0005] Although the injection molding grade PAI is an improvement over high molecular weight PAI, there are still many difficulties in melt processing. As mentioned above, amic acid groups still exist in the chain-extended PAI, so it must be thoroughly dried before use. A thermal post-treatment step is also required to complete the polymerization (chain extension) and / or imidization of the amic acid groups. As mentioned above, water is generated in these post-treatment steps and must be removed to avoid blistering, formation of microbubbles and embrittlement of the parts. There are also other difficulties with injection molding grade PAI. The residence time must be optimized because too long a residence time will result in flow losses due to chain extension and increased viscosity. The mold must be filled quickly, and the pressure must be optimized for each mold size and shape. Injection molding using a home mold design is not satisfactory. The viscosity of injection molding grade PAI is still highly shear-sensitive. Therefore, the injection speed, injection pressure, back pressure, screw speed, barrel temperature, cycle time and mold heating must all be optimized for each specific mold shape and size.

[0006] Post-heat treatment remains crucial for injection molding grade PAI. Although the molded parts may appear to be finished, they are actually fragile, brittle, have poor chemical and wear resistance, and also have unsatisfactory heat resistance. To obtain optimal performance, the molded parts must be heated in a forced air oven according to a curing schedule with a series of incremental temperature increases at certain time intervals, which must be optimized for each type and size of part. The general curing schedule recommended by the manufacturer is: 375°F (191°C) for 1 day, 425°F (218°C) for 1 day, 475°F (246°C) for 1 day, and 500°F (260°C) for 5 days, for a total of 8 days. Thicker parts may require longer curing times because the water for the reaction must diffuse out of the part for the reaction to occur. Thus, the reaction rate decreases as the diffusion path lengthens. In addition, certain parts, such as those with very thin walls and / or delicate features, may need to be fixed during post-curing to meet strict dimensional tolerances.

[0007] In view of the above problems, there is still a need in the art for PAI that is easily melt-processable and curable, which does not require extensive drying before processing and does not require extensive post-heat treatment to remove the water generated by the cyclodehydration of amic acid functional groups. There is also a need for PAI that is suitable for various article manufacturing processes, for example, for direct injection molding of complex shapes, for manufacturing unidirectional tapes and fiber-reinforced composites using continuous fibers, and for 3D printing applications, such as fused deposition modeling (FDM) using filaments or rods, or powder bed printing, such as selective laser sintering (SLS). The subject matter described herein addresses these drawbacks in the art and more. Summary of the Invention

[0008] The reactive polyamide-imide oligomer comprises units derived from at least one aromatic diamine, at least one aromatic di-, tri-, or tetra-functional carboxylic acid or its functional equivalent, and at least one crosslinkable monomer or crosslinkable capping agent; wherein the crosslinkable monomer or crosslinkable capping agent is reactive with at least one aromatic diamine or at least one di-, tri-, or tetra-functional aromatic carboxylic acid or its functional equivalent, and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive polyamide-imide oligomer; wherein the reactive polyamide-imide oligomer has a number average molecular weight (M n ) of about 1000 to about 10000 g / mol as calculated using the Carothers equation. "Derived from" means that the reactive polyamide-imide oligomer is formed by stepwise growth polymerization of at least one aromatic diamine, at least one aromatic di-, tri-, or tetra-functional carboxylic acid or its functional equivalent, and at least one crosslinkable monomer or crosslinkable capping agent, and by cyclodehydration of the resulting polyamide amic acid oligomer intermediate, with the formation of small molecules such as water and hydrochloric acid as by-products.

[0009] The method for manufacturing a reactive polyamideimide oligomer includes: copolymerizing at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or its functional equivalent, and at least one crosslinkable monomer or crosslinkable capping agent in the presence of a polar solvent to form a reactive polyamideamic acid oligomer; and heating the reactive polyamideamic acid oligomer at a sufficient temperature and for a sufficient time to prepare a reactive polyamideimide oligomer; wherein the crosslinkable monomer or crosslinkable capping agent is reactive with at least one aromatic diamine or at least one di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent, and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive polyamideimide oligomer.

[0010] Another method for manufacturing a reactive polyamideimide oligomer includes: heating at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or its functional equivalent, and at least one crosslinkable monomer or crosslinkable capping agent in the presence of C 1-4 alcohol at a temperature and for a time sufficient to form at least one reactive ammonium carboxylate salt; optionally removing the excess C 1-4 alcohol; and heating the reactive ammonium carboxylate salt at a temperature and for a time sufficient to form a reactive polyamideimide oligomer; wherein the crosslinkable monomer or crosslinkable capping agent is reactive with the at least one aromatic diamine or the at least one di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent, and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive polyamideimide oligomer.

[0011] The method for manufacturing an article includes heating a reactive polyamideimide oligomer at a temperature and for a time sufficient to shape and crosslink the reactive polyamideimide oligomer. The method can be additive manufacturing, fiber-reinforced composite manufacturing, pultrusion, fiber spinning, compression molding, injection molding, reaction injection molding, blow molding, rotational molding, transfer molding, foam molding, thermoforming, casting, solution casting or forging. An article manufactured by this method is also disclosed.

[0012] The reactive polyamideamic acid oligomer contains units derived from at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or its functional equivalent, and at least one crosslinkable monomer or crosslinkable capping agent, wherein the crosslinkable monomer or crosslinkable capping agent is reactive with the at least one aromatic diamine or the at least one di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent, and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive polyamideamic acid oligomer; wherein the reactive polyamideamic acid oligomer has a number average molecular weight (M n ) of about 1000 to about 10000 g / mol calculated using the Carothers equation.

[0013] The method for manufacturing a reactive polyamide polyamic acid oligomer includes: copolymerizing at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or its functional equivalent, and at least one crosslinkable monomer or crosslinkable capping agent in the presence of a polar solvent to form a reactive polyamide polyamic acid oligomer; wherein the crosslinkable monomer or crosslinkable capping agent is reactive with the at least one aromatic diamine or the at least one di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent, and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive polyamide polyamic acid oligomer.

[0014] The method for manufacturing an article includes heating a reactive polyamide polyamic acid oligomer at a temperature and for a time sufficient to imidize, shape and crosslink the reactive polyamide polyamic acid oligomer. The method can be additive manufacturing, fiber-reinforced composite manufacturing, pultrusion, fiber spinning, compression molding, injection molding, reaction injection molding, blow molding, rotational molding, transfer molding, foam molding, thermoforming, casting, solution casting or forging. An article manufactured by this method is also disclosed.

[0015] The reactive carboxylic acid ammonium salt is formed by the following method: heating at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or its functional equivalent, and at least one crosslinkable monomer or crosslinkable capping agent in the presence of at least one of water or C 1-4 alcohol at a temperature and for a time sufficient to form the reactive carboxylic acid ammonium salt; and removing the excess water and C 1-4 alcohol; wherein the crosslinkable monomer or crosslinkable capping agent is reactive with the at least one aromatic diamine or the at least one di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent, and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive carboxylic acid ammonium salt.

[0016] The method for manufacturing a reactive carboxylic acid ammonium salt includes: heating at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or its functional equivalent, and at least one crosslinkable monomer or crosslinkable capping agent in the presence of at least one of water or C 1-4 alcohol at a temperature and for a time sufficient to form the reactive carboxylic acid ammonium salt; and removing the excess C 1-4 alcohol; wherein the crosslinkable monomer or crosslinkable capping agent is reactive with the at least one aromatic diamine or the at least one di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent, and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive carboxylic acid ammonium salt.

[0017] The method for manufacturing an article includes heating a reactive ammonium carboxylate salt at a temperature, pressure, and time sufficient to produce, shape, and crosslink a reactive polyamideimide oligomer. The method can be fiber-reinforced composite manufacturing, pultrusion, compression molding, injection molding, or solution casting. An article manufactured by the method is also disclosed. Description of the Drawings

[0018] Now referring to the drawings:

[0019] Figure 1 An exemplary composite panel prepared as in Example 4 is depicted. Four layers of carbon fiber fabric T650 were impregnated with a reactive polyamideimide oligomer (M n = 5000 g / mol, fully imidized, molten) and consolidated using a heated parallel plate press to prepare the composite panel.

[0020] Figure 2 A through 2D illustrate the concepts of interfacial diffusion and chain entanglement and crosslinking across the interface. Figure 2 A and 2B depict the diffusion and entanglement of high molecular weight high performance thermoplastics. Figure 2 C and 2D depict the diffusion, entanglement, chain extension, and crosslinking of reactive oligomers.

[0021] Figure 3 is a graph of the axial force (N) versus time (min) for the melt polymerization of 1,3-benzenediamine, 4,4'-oxydianiline, trimellitic anhydride, and 4-(phenylethynyl)phthalic anhydride in a twin screw extruder. Detailed Description

[0022] Reactive polyamideimide oligomers and reactive polyamide amic acid oligomers (collectively referred to herein as "reactive oligomers"), reactive ammonium carboxylate salts, methods for manufacturing reactive oligomers and reactive ammonium carboxylate salts, methods for processing reactive oligomers and reactive ammonium carboxylate salts, and articles made from reactive oligomers and reactive ammonium carboxylate salts are disclosed herein. The approach for obtaining the polyamideimide articles described herein eliminates the need for extended thermal post-curing and time-consuming water removal steps. This is achieved by designing a fully imidized reactive polyamideimide oligomer that can be melt processed and then thermally post-cured for a short period (up to a few hours) to produce a high molecular weight polyamideimide through chain extension / crosslinking. The latter reaction occurs by incorporating carefully selected functional groups into the reactive polyamideimide oligomer. These functional groups remain unreacted during the oligomerization process and can then be used for thermal post-curing. During the thermal post-curing process, these functional groups can polymerize (chain extend / crosslink) through addition reactions without producing small molecule by-products such as water.

[0023] The reactive polyamideimide oligomers described herein allow the production of profiles, complex injection-molded parts, 3D printed parts, and fiber- or mineral-reinforced composites without any thickness limitations, as the step of removing water from the final product is no longer required. These routes to obtaining polyamideimide not only provide processing advantages (e.g., low viscosity, no residual water, no water generation), but also allow the design and manufacture of PAI articles that were previously impossible to fabricate.

[0024] Having an M in the range of about 1000 to about 10000 g / mol n provides a lower melt viscosity and a lower processing temperature, enabling melt processing using conventional melt processing equipment. However, low molecular weight polymers (oligomers) are known to have poor mechanical properties as they lack polymer chain entanglements. The use of crosslinkable monomers and / or crosslinkable end-capping agents in the preparation of reactive oligomers can increase the molecular weight by in-situ thermal polymerization (e.g., during reaction injection molding) or during a post-thermal treatment step (e.g., when preparing fiber-reinforced composites).

[0025] Reactive polyamideimide oligomers having thermally curable groups have several advantages. Reactive polyamideimide oligomers are easy to melt process, do not require extensive drying before processing, and do not require extensive post-thermal treatment. Complex parts can be made in one step from reactive polyamideimide oligomers. Curing can be carried out at about 300 to about 450 °C and can be completed in as little as about 1 to about 60 minutes compared to several days for currently available grades of PAI. When the reactive polyamideimide oligomers are fully imidized before melt processing, the difficult step of removing water from profiles or injection-molded parts is not required. Advantageously, reactive polyamideimide oligomers can be used for the one-step injection molding of complex parts under conditions where the reactive oligomers cure instantaneously. Alternatively, the parts can be easily thermally cured for about 1 to about 60 minutes. In addition, the T of the cured reactive polyamideimide oligomers g , elongation at break, tensile strength at break, and toughness can be far superior to currently available PAI.

[0026] The reactive polyamideimide oligomers comprise units derived from at least one aromatic diamine, at least one aromatic di-, tri-, or tetra-functional carboxylic acid or its functional equivalent, and at least one crosslinkable monomer or crosslinkable end-capping agent; wherein the crosslinkable monomer or crosslinkable end-capping agent is reactive with at least one aromatic diamine or at least one di-, tri-, or tetra-functional aromatic carboxylic acid or its functional equivalent and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive polyamideimide oligomer; and the number average molecular weight (M n ) of the reactive polyamideimide oligomer is calculated using the Carothers equation to be about 1000 to about 10000 g / mol.

[0027] The reactive polyamideimide oligomer comprises units derived from at least one aromatic diamine. The at least one aromatic diamine can have any chemical structure described below.

[0028]

[0029] In some aspects, the at least one diamine is at least one of 1,3-benzenediamine, 4,4'-oxydianiline or 3,4'-oxydianiline.

[0030] The reactive polyamideimide oligomer further comprises at least one aromatic di-, tri- or tetra-functional carboxylic acid or a functional equivalent thereof. A functional equivalent of a carboxylic acid is a functional group in which the carboxyl carbon atom is in the same oxidation state, such as a carboxylic acid ester, a carboxylic acid halide and a carboxylic anhydride. For example, a trimellitic anhydride functional equivalent is a compound in which the substituent carbon atoms at the 1-, 2- and 4-positions on the benzene ring are in the same oxidation state. A functional equivalent of trimellitic anhydride is 4-chlorocarbonyl phthalic anhydride. The at least one aromatic di-, tri- or tetra-functional carboxylic acid or a functional equivalent thereof includes at least one aromatic di-, tri- or tetra-functional carboxylic acid or a functional equivalent thereof having an ortho (o) carboxylic acid or a functional equivalent group (such as a phthalic anhydride group) so that a 5-membered phthalimide ring can be formed in the reactive oligomer backbone. The at least one aromatic di-, tri- or tetra-functional carboxylic acid or a functional equivalent thereof can have any chemical structure described below.

[0031]

[0032] In some embodiments, the at least one aromatic di-, tri- or tetra-functional carboxylic acid or a functional equivalent thereof is at least one of trimellitic anhydride, 4-chlorocarbonyl phthalic anhydride, isophthalic anhydride, isophthaloyl chloride, pyromellitic dianhydride or biphenyltetracarboxylic dianhydride.

[0033] The reactive polyamideimide oligomer further comprises at least one crosslinkable monomer or crosslinkable capping agent that is reactive with at least one aromatic diamine or at least one di-, tri- or tetra-functional aromatic carboxylic acid or a functional equivalent thereof and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive polyamideimide oligomer. This functional group remains unreacted after the formation of the reactive polyamideimide oligomer and can thus be used to participate in subsequent chain extension, branching and crosslinking reactions. The chain extension, branching and crosslinking that occur after the formation of the reactive polyamideimide oligomer are collectively referred to as "curing". As used herein, "crosslinking" is also a shorthand for any combination of chain extension, branching and crosslinking. Curing or crosslinking can be initiated by heat, actinic (electromagnetic) radiation and electron beam radiation. In some embodiments, curing is heat-initiated. The unreacted functional groups participating in subsequent chain extension, branching and crosslinking reactions are at least one of acetylene, methylacetylene, phenylacetylene, ketoacetylene, propargyl ether, norbornene, maleimide, cyanate ester, phthalonitrile, benzocyclobutene, biphenyl or benzoxazine. These unreacted functional groups are described in Table 1 by chemical formula, chemical name and curing temperature range. At least one crosslinkable monomer or crosslinkable capping agent can be two crosslinkable monomers or crosslinkable capping agents that are reactive in different temperature ranges.

[0034] Table 1. Functional groups capable of thermal chain extension, branching and crosslinking and curing temperature ranges.

[0035]

[0036]

[0037]

[0038] Examples of crosslinkable capping agents and crosslinkable monomers with names for unreacted functional groups are provided below. 1,2-Diphenylacetylene is a crosslinkable monomer. All other compounds are crosslinkable capping agents. In some embodiments, the crosslinkable monomer or crosslinkable capping agent is at least one of 4-ethynylphthalic anhydride, 4-methyl-ethynylphthalic anhydride, 4-phenyl-ethynylphthalic anhydride (PEPA) or 4,4'-(ethyne-1,2-diyl)diphthalic anhydride.

[0039]

[0040]

[0041] The reactive polyamideimide oligomer may also contain units derived from at least one non-crosslinkable capping agent, where the non-crosslinkable capping agent is reactive with at least one aromatic diamine or at least one di-, tri-, or tetra-functional aromatic carboxylic acid or its functional equivalent, but does not have unreacted functional groups capable of chain extension and crosslinking after the formation of the reactive polyamideimide oligomer. The non-crosslinkable capping agent may be at least one of benzoic acid, benzoyl chloride, phthalic anhydride, or aniline.

[0042] The reactive polyamideimide oligomer can be linear or branched. In some embodiments, the reactive polyamideimide oligomer is branched. Branching is obtained by using trifunctional monomers. Thus, in some embodiments, the reactive polyamideimide oligomer also contains units derived from at least one of an aromatic triamine, an aromatic tricarboxylic acid, or an aromatic tricarboxylic acid chloride. Examples of aromatic triamines are 1,3,5-triaminobenzene, examples of aromatic tricarboxylic acids are 1,3,5-benzenetricarboxylic acid, and examples of aromatic tricarboxylic acid chlorides are 1,3,5-benzenetricarboxylic acid chloride.

[0043] The number average molecular weight M n is a target value, not a measured value. The amounts of monomers and crosslinkable capping agents for preparing the reactive oligomer are calculated using the Carothers equation, Eq. (2). Eq. (1) is used to calculate the degree of polymerization required to reach the target

[0044]

[0045] (also referred to herein as M n ) is the target number average molecular weight, selected from the range of about 1000 to about 10000 g / mol) and is the average molecular weight of the oligomer repeating unit. Given and , the number average degree of polymerization is calculated and substituted into Eq. 2. Assuming complete reaction, so p = 1, which simplifies Eq. 2 to an equation with one unknown, r, which is the reactant ratio, and provides the stoichiometric offset required to prepare the desired reactive oligomer at the target .

[0046] Polyamide amic acid is an intermediate in the synthesis of polyamideimide. As shown in Scheme 1 below, polyamideimide is produced by cyclodehydration of the intermediate polyamide amic acid (upper right structure).

[0047] Scheme 1

[0048]

[0049] Since polyamide acid is an intermediate for preparing polyamideimide, the reactive polyamideimide oligomer can have different degrees of imidization, i.e., the polyamide acid intermediate is converted to polyamideimide. Thus, in some embodiments, the reactive polyamideimide oligomer is derived by dehydration cyclization from a reactive polyamide acid oligomer intermediate, and greater than about 80% and less than or equal to 100% of the amide acid groups in the reactive polyamide acid intermediate are imidized. When the degree of imidization is within this range, the reactive polyamideimide oligomer is considered to be "fully imidized". Within this range, greater than or equal to 85%, 90%, 95%, 96%, 97%, 98% and 99% and less than or equal to 100% of the polyamide acid groups can be imidized.

[0050] In some applications, less than 80% imidization of the reactive polyamideimide oligomer may be useful. Thus, in some embodiments, the reactive polyamideimide oligomer is derived by dehydration cyclization from a reactive polyamide acid oligomer intermediate, and greater than or equal to 20% and less than or equal to 80% of the amide acid groups in the reactive polyamide acid intermediate are imidized. Within this range, greater than or equal to 30%, 40%, 50%, 60% and 70% and less than or equal to 80% of the amide acid groups can be imidized.

[0051] Advantageously, the reactive polyamide oligomer has a melt complex viscosity of about 1000 to about 100000 Pa·s at 360 °C, which is measured by oscillatory shear rheology between parallel plates at a heating rate of 10 °C / minute, a frequency of 2 radians / second, and a strain of 0.03% to 1.0% under N 2 Under these conditions, the melt complex viscosity is a function of M n and at least one diamine, at least one di-, tri- or tetra-functional aromatic carboxylic acid or a functional equivalent thereof, and the type and relative amounts of crosslinkable or non-crosslinkable monomers and end-capping agents used to make the reactive polyamide oligomer. Thus, the melt complex viscosity as a function of shear rate, time, temperature and heating rate can be adjusted by selecting the monomers and reactive and non-reactive end-capping agents and their relative amounts. For example, the melt complex viscosity can be greater than or equal to 2000, 3000, 4000 or 5000 Pa·s and less than or equal to 90000, 70000, 50000 or 30000 Pa·s. In some embodiments, the melt complex viscosity is about 5000 to about 30000 Pa·s at 360 °C. In contrast, currently available PAI is reported to have a melt complex viscosity of 100000 Pa·s at 2 radians / second.

[0052] The reactive polyamideimide oligomer can be manufactured by a method comprising: copolymerizing at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or its functional equivalent, and at least one crosslinkable monomer or crosslinkable capping agent in the presence of a polar solvent to form a reactive polyamideamic acid; heating the reactive polyamideamic acid oligomer at a sufficient temperature and for a sufficient time to prepare the reactive polyamideimide oligomer; wherein the crosslinkable monomer or crosslinkable capping agent is reactive with at least one aromatic diamine or at least one di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent, and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive polyamideimide oligomer. The manufacture of exemplary reactive polyamideimide oligomers is provided in Scheme 2.

[0053] Scheme 2

[0054]

[0055] A – Synthesis of reactive polyamideimide oligomer with only one crosslinkable capping agent;

[0056] B – Synthesis of reactive polyamideimide oligomer with two different crosslinkable capping agents;

[0057] C – Synthesis of reactive polyamideimide oligomer from dianhydride (tetra-functional) and diacid / diacyl chloride (di-functional) with only one crosslinkable capping agent;

[0058] D – Synthesis of reactive polyamideimide oligomer from crosslinkable monomer and non-crosslinkable capping agent; and

[0059] E – Synthesis of reactive polyamideimide oligomer from crosslinkable monomer and crosslinkable capping agent.

[0060] The sufficient temperature and time for preparing the reactive polyamideimide oligomer are about 140 °C to about 220 °C for about 1 minute to about 120 minutes. As described above, the reactive polyamideimide oligomer is manufactured by forming a reactive polyamideamic acid oligomer intermediate. The temperature and time required for imidizing the reactive polyamideamic acid oligomer intermediate in this method depend on the presence or absence of a polar solvent, the specific reactive polyamideimide oligomer prepared, and the degree of imidization required. When imidization is carried out in the absence of a solvent, that is, using a pure solid-state reactive polyamideamic acid oligomer, the sufficient temperature and time for preparing the reactive polyamideimide oligomer are about 220 °C to about 300 °C for about 1 minute to about 120 minutes. When imidization is carried out in the presence of a polar solvent, the sufficient temperature and time for preparing the reactive polyamideimide oligomer are about 140 °C to about 220 °C for about 1 minute to about 120 minutes.

[0061] The reactive polyamideimide oligomer is manufactured in the presence of a polar solvent, which reduces the temperature range sufficient to prepare the reactive oligomer. The boiling point of the polar solvent at one atmosphere should be at least 150 °C. The polar solvent can be at least one of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, 1,2-dichlorobenzene, 1,2,4-trichlorobenzene, or sulfolane. In some embodiments, the polar solvent is N-methyl-2-pyrrolidone. The manufacturing method may further include removing the polar solvent from the polyamide amic acid oligomer before heating the reactive polyamide amic acid oligomer to a temperature and for a time sufficient to prepare the reactive polyamideimide oligomer.

[0062] There are different methods for the imidization of the reactive polyamide amic acid oligomer. The reactive polyamideimide oligomer can be prepared by adding toluene to the reactive polyamide amic acid oligomer and azeotropically distilling the toluene with water. The reactive polyamideimide oligomer can also be prepared by subjecting the reactive polyamide amic acid oligomer to microwave irradiation. The imidizing agent can be acetic anhydride. Acidic by-products are produced upon imidization, such as acetic acid when acetic anhydride is used. Thus, a base, such as a tertiary amine, can be used. The tertiary amine can be, for example, pyridine or triethylamine. Thus, in some embodiments, the reactive polyamideimide oligomer is prepared by heating the reactive polyamide amic acid oligomer in the presence of acetic anhydride and a catalytic amount of a tertiary amine.

[0063] Another method for manufacturing the reactive polyamideimide oligomer is to carry out copolymerization in the presence of a phosphorylating agent and a catalytic amount of a salt. In this method, di-, tri-, or tetra-functional carboxylic acids or their functional equivalents do not include acid halides, such as acid chlorides. The advantage of this method is that expensive acid chlorides are not required as starting materials. For example, copolymerization is carried out in the presence of triphenyl phosphite, a polar solvent such as NMP as the solvent, and a catalytic amount of a salt such as LiCl or CaCl 2 in the presence. Heating to 120 °C for 1.5 to 2 hours under nitrogen results in the formation of the reactive polyamide amic acid oligomer and partial imidization to the corresponding reactive polyamideimide oligomer. Further heating to 150 °C for up to 5 hours under nitrogen with additional pyridine provides complete imidization.

[0064] Reactive polyamideimide oligomers can also be prepared by reactive extrusion. Accordingly, a method for making reactive polyamideimide oligomers includes reactive extrusion of at least one aromatic diamine or its activated derivative (such as diacetylated diamine), at least one aromatic di-, tri-, or tetra-functional carboxylic acid or its functional equivalent, and at least one crosslinkable monomer or crosslinkable capping agent at a temperature and for a time sufficient to prepare the reactive polyamideimide oligomer; wherein the crosslinkable monomer or crosslinkable capping agent is reactive with at least one aromatic diamine or at least one di-, tri-, or tetra-functional aromatic carboxylic acid or its functional equivalent and has at least one unreacted functional group capable of chain extension and crosslinking after formation of the reactive polyamideimide oligomer.

[0065] Reactive extrusion can be carried out in the presence of a polar solvent. The polar solvent can be at least one of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, 1,2-dichlorobenzene, 1,2,4-trichlorobenzene, or sulfolane. In some embodiments, the polar solvent is N-methyl-2-pyrrolidone. The polar solvent can dissolve the monomers, or, can partially dissolve the monomers and together with the oligomers and intermediates formed during the reactive extrusion form a fluid suspension or slurry of the monomers.

[0066] Reactive extrusion can be carried out in the presence of an acid catalyst to promote imidization (cyclic dehydration) of the amic acid intermediate. When in the liquid state under reactive extrusion conditions, the acid catalyst can also partially dissolve the monomers and together with the oligomers and intermediates formed during the reactive extrusion form a fluid suspension or slurry of the monomers. When the acid catalyst is a liquid, it can be removed by distillation through an exhaust port during reactive extrusion. In some embodiments, the acid catalyst is acetic acid and is removed by distillation during reactive extrusion. Reactive extrusion can also be carried out in the presence of acetic anhydride, where the acetic anhydride is removed by distillation during reactive extrusion. To facilitate removal of any water, HCl, polar solvent, acid catalyst, and acetic anhydride present or generated, reactive extrusion can be carried out in a melt extruder having a plurality of preset heating zones equipped with exhaust ports or other means for removing these volatiles.

[0067] Reactive polyamideimide oligomers can also be made by the "ammonium carboxylate salt" method. The ammonium carboxylate salt method includes: heating at least one aromatic diamine, at least one aromatic di-, tri-, or tetra-functional carboxylic acid or its functional equivalent, and at least one crosslinkable monomer or crosslinkable capping agent in the presence of at least one of water or C 1-4 alcohol at a temperature and for a time sufficient to form at least one reactive ammonium carboxylate salt; removing the excess water and C 1-4An alcohol; and heating the reactive ammonium carboxylate at a temperature and for a time sufficient to form a reactive polyamideimide oligomer; wherein the crosslinkable monomer or crosslinkable capping agent is reactive with at least one aromatic diamine or at least one di-, tri- or tetra-functional aromatic carboxylic acid or a functional equivalent thereof, and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive polyamideimide oligomer. C 1-4 The alcohol can be at least one of, for example, methanol, ethanol, 1-propanol, isopropanol, 1-butanol, isobutanol, sec-butanol or tert-butanol. In some embodiments, C 1-4 The alcohol is at least one of methanol or ethanol. An exemplary reactive polyamideimide oligomer made by the ammonium carboxylate method is described in Scheme 3 below.

[0068] Scheme 3

[0069]

[0070] The acid anhydride and diamine are in C 1-4 an alcohol (such as methanol or ethanol) and heated at 70 °C for 1 hour. This will cause the acid anhydride to ring open and form the corresponding alkyl half-ester of the dicarboxylic acid, such as the methyl or ethyl half-ester. The solvent is then removed by vacuum distillation. Thus, the reactive ammonium carboxylate is a mixture of all possible combinations of Ar-COO - and + H 3 N-Ar, where Ar represents an aryl group, and where Ar-COO - is C 1-4Alkyl half esters. Ammonium carboxylates (similar to nylon salts) can be converted into reactive polyamideimide oligomers by polymerization and imidization, which can be accomplished in a variety of ways. Polymerization and imidization can be carried out by heating the dry reactive ammonium carboxylate in an inert atmosphere, preferably at a pressure (0 to 300 MPa) and heated to 300 °C to obtain reactive polyamideimide oligomers. (Option 1 in Scheme 3) The heating can be carried out in a sealed container (Option 1 in Scheme 3) and / or in an extruder having the ability to exhaust water and methanol or ethanol vapors. (Option 2 in Scheme 3) For example, the reactive ammonium carboxylate can be gradually heated in a sealed container in an inert atmosphere at 60, 100, and 200 °C for 1 hour each, then cooled to 25 °C, and then oligomerized in an extruder at 320 to 360 °C to obtain reactive polyamideimide oligomers. Thus, in some embodiments, the method includes reactive extrusion of the reactive ammonium carboxylate at a temperature and for a time sufficient to form reactive polyamideimide oligomers. Polymerization and imidization can also be carried out by dissolving the reactive ammonium carboxylate in at least one polar solvent, such as water, N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, 1,2-dichlorobenzene, 1,2,4-trichlorobenzene, or sulfolane, and then heating to 160 °C. (Option 3 in Scheme 3) Thus, in some embodiments, the method includes dissolving the reactive ammonium carboxylate in a polar solvent and then heating at a temperature, pressure, and for a time sufficient to form reactive polyamideimide oligomers.

[0071] Alternatively, at least one aromatic diamine, at least one aromatic di-, tri-, or tetra-functional carboxylic acid or a functional equivalent thereof, and at least one crosslinkable monomer or crosslinkable capping agent can be mixed with water, methanol, ethanol, a mixture of methanol / water, or a mixture of ethanol / water, and then heated to 220 °C in a pressure-resistant container (bomb calorimeter or autoclave) to polymerize and imidize the reactive ammonium carboxylate.

[0072] Advantageously, the reactive ammonium carboxylate has a complex melt viscosity of about 1 to about 100 Pa·s in the temperature range of about 80 to about 120 °C, and a solubility in a polar solvent such as NMP at 60 °C of up to 70 to 80 wt%. The low complex melt viscosity and high solubility of the reactive ammonium carboxylate allow for high-yield manufacture of reactive polyamideimide oligomers.

[0073] Reactive polyamideimide oligomers can be used to prepare various functional materials with useful properties. Thus, the mixture composition comprises a reactive polyamideimide oligomer and a thermoplastic polymer. For example, reactive polyamideimide oligomers and reactive polyamide amic acid oligomers can be used as plasticizers or reactive diluents to improve the processability of high molecular weight PAI polymers and other high molecular weight polymers. Compared with high molecular weight PAI, the reactive oligomers added to the PAI polymer can shorten the compression molding cycle by improving fluidity and improving consolidation (minimizing voids).

[0074] Another example of a functional material is a powder coating composition comprising a reactive polyamideimide oligomer. The reactive polyamideimide oligomer in powder form can be used to prepare coatings on various substrates such as metals, ceramics, glass, and composite substrates. The powder coatings can employ thermal spraying, vacuum plasma spraying, and cold spraying techniques.

[0075] Another example of a functional material is a reactive adhesive composition comprising a reactive polyamideimide oligomer. The reactive adhesive composition in powder form can be applied to a variety of substrates (with or without pretreatment), melted, and cured under pressure at a temperature of 350 to 400 °C. Substrates include glass, titanium, steel, and any material capable of withstanding high temperature curing. The reactive powder can be mixed with inert spherical fillers to control the adhesive layer thickness (such as glass beads). The reactive adhesive can also be melted into a fabric to make a reactive tape, which can be placed between two substrates, heated, and cured under pressure.

[0076] Another example of a functional material is a high-temperature elastomer composition, which is made by heating a reactive polyamideimide oligomer at a temperature and for a time sufficient to crosslink the reactive polyamideimide oligomer. Components made of neat, filled, or fiber-reinforced crosslinked parts can be used as high-temperature elastomers for sealant and gasket applications.

[0077] Another example of a functional material is a high-temperature foam comprising a reactive polyamideimide oligomer.

[0078] To improve physical properties, it may be necessary to compound the reactive polyamideimide oligomer with other materials. Thus, a method for synthesizing a reactive polyamideimide oligomer includes mixing the reactive polyamideimide oligomer with at least one other material at a temperature and for a time sufficient to melt the reactive polyamideimide oligomer but not crosslink it. The material can be at least one polymer, filler, or additive. For example, the reactive polyamideimide oligomer can be compounded with other reactive polyamideimide oligomers and / or reactive polyamide amic acid oligomers to improve thermomechanical properties. The reactive polyamideimide oligomer can also be used to prepare block copolymers with other reactive polyamideimide oligomers and / or reactive polyamide amic acid oligomers to improve thermomechanical properties.

[0079] The reactive oligomer can be used to fabricate a variety of articles or components having useful properties. Thus, a method for fabricating an article includes heating the reactive polyamideimide oligomer at a temperature and for a time sufficient to shape and crosslink the reactive polyamideimide oligomer. The temperature and time sufficient to shape and crosslink the reactive oligomer are from about 300 to about 450 °C for about 1 to about 60 minutes. Exemplary curing conditions are from about 350 to about 400 °C for about 30 to about 60 minutes, such as about 360 °C for about 45 minutes.

[0080] For example, the fabrication method can be additive manufacturing, fiber-reinforced composite manufacturing, pultrusion, fiber spinning, compression molding, injection molding, reaction injection molding, blow molding, rotational molding, transfer molding, foam molding, thermoforming, casting, solution casting, or forging.

[0081] Also disclosed are articles fabricated by this method. Various fabrication methods and articles made by this method are described below.

[0082] The fabrication method can be fiber-reinforced composite manufacturing. The reactive polyamideimide oligomer can be present in a film powder. Thus, fiber-reinforced composite manufacturing can include heating at least one layer of fiber fabric and at least one layer of reactive polyamideimide oligomer to a powder or film at a temperature, pressure, and time sufficient to melt the reactive polyamideimide oligomer, impregnating the fiber fabric, and crosslinking the reactive polyamideimide oligomer to form a fiber-reinforced composite.

[0083] The reactive polyamideimide oligomer can also be dissolved in a polar solvent. Accordingly, a fiber-reinforced manufacturing method can include impregnating at least one layer of fiber fabric with a solution of the reactive polyamideimide oligomer dissolved in a polar solvent; removing the polar solvent under reduced pressure; and heating at a temperature, pressure, and time sufficient to crosslink the reactive polyamideimide oligomer and form a fiber-reinforced composite. For example, the fiber can be carbon fiber, glass fiber, cellulose (wood fiber / paper fiber, straw), polyamine (poly-p-phenylene terephthalamide), polybenzoxazole (PBO), or polybenzimidazole (PBI).

[0084] Also disclosed is a fiber-reinforced composite manufactured by any of the above methods. For example, the composite can be a multi-layer carbon-reinforced composite. The multi-layer reinforced composite can have any number of layers, but in some embodiments, the number of layers is greater than or equal to 2 and less than or equal to 1000 layers.

[0085] The manufacturing method can be pultrusion for making unidirectional tapes. As with fiber-reinforced composite manufacturing, pultrusion can be from a melt or solution of the reactive polyamideimide oligomer in a polar solvent. Also disclosed is an unidirectional tape prepared by pultrusion. The unidirectional (UD) tape can be a plain tape, a slit tape, a roving, or a tow tape. The UD tape can be used in tape laying technology / TOW robots for manufacturing fiber-reinforced composites.

[0086] The manufacturing method can be solution spinning or melt spinning of fibers. Also disclosed are fibers manufactured by solution spinning or melt spinning. The reactive polyamide amic acid oligomer and M n Reactive polyamide amine oligomers with a molecular weight of about 100 g / mol to about 10,000 g / mol can be spun into fibers from a solution state or a melt state. In solution spinning, the reactive oligomer dissolved in a suitable polar solvent or polar solvent mixture (such as NMP, DMAc, DMF, or NMP / THF) can be spun into fibers using a standard solution spinning apparatus (including a plunger pump and a spinneret operating at 25°C to 80°C). The fibers are obtained after coagulation in a non-solvent (such as water / acetone at -10°C to 60°C). The resulting fibers are dried and heated to induce imidization and crosslinking. The as-spun fibers can also be dried using a hot air stream followed by an additional heating step. During the heat treatment, the fibers can be exposed to a stretching step, which increases the alignment of the polymer chains along the stretching direction, thereby improving fiber strength. In melt spinning, the reactive polyamideimide oligomer is melted and spun into fibers through a spinning apparatus that includes a plunger pump, a heated resin chamber (250°C to 300°C), and a heated spinneret operating at 300°C to 400°C to induce crosslinking. The hot drawn fibers can be cooled (air / water) and wound, and then subjected to a second heating step with or without post-drawing to complete crosslinking and increase fiber strength.

[0087] The manufacturing method can be additive manufacturing. Articles manufactured by additive manufacturing are also disclosed. In some embodiments of additive manufacturing, the method is fused filament fabrication. Fused filament fabrication involves extruding reactive polyamideimide oligomers in adjacent horizontal layers such that there is an interface between the layers of polyamideimide oligomers and exposing the layers to heat at a temperature and for a time sufficient to crosslink the reactive polyamideimide oligomers and form the article. Articles manufactured by fused filament fabrication are also disclosed.

[0088] Fused filament fabrication uses material extrusion to print articles, where the raw material is pushed through an extruder. In most fused filament fabrication 3D printers, the raw material comes in the form of a filament wound on a spool. The 3D printer liquefier is the main component used in such printing. The extruders of these printers have a hot end and a cold end. The "cold" end is colder than the hot end, but can still be in the temperature range of 100 to 250 °C. Using a gear or roller-based torque is applied to the material and the feed rate is controlled by a stepper motor. The cold end pulls the material from the spool and pushes the raw material into the hot end. The hot end consists of a heating chamber and a nozzle. The heating chamber houses the liquefier, which melts the raw material to convert it to a molten state. It allows the molten material to leave through a small nozzle, forming a thin and sticky plastic bead that adheres to the material on which it is laid. The diameter of the nozzle is typically between 0.3 mm and 1.0 mm. Different types of nozzles and heating methods are used depending on the material to be printed.

[0089] The filament can be in the form of a thin wire wound on a spool. In a variant of this method, the raw material is in the form of a rod instead of a filament. Since the rod is thicker than the filament, it can be pushed towards the hot end by a piston or a spool, applying a greater force and / or speed compared to traditional fused filament fabrication.

[0090] The weld line is defined as the planar interface between adjacent extruded material layers. The reactive polyamideimide oligomers diffuse across the interface and react to rapidly increase polymer chain entanglements and network formation across the interface, thereby fusing the adjacent layers together. The weld line (interface) is further strengthened by chain extension and / or crosslinking of the reactive polyamideimide oligomers entangled across the interface, thereby improving the z-axis strength.

[0091] By using reactive polyamideimide oligomers with two different reactive end groups, the chain entanglement, network formation, chain extension, and crosslinking processes in fused filament fabrication can be optimized. Oligomer chains containing a first unreacted functional group with a first curing temperature can be crosslinked first to fix the printed structure in place. Oligomer chains containing a second unreacted functional group with a second curing temperature higher than the first curing temperature can diffuse across the interface and cure at the second curing temperature, forming the molecular weight, crosslink density, and strength of the part.

[0092] In some embodiments of additive manufacturing, the method is selective laser sintering. Selective laser sintering involves selectively sintering and crosslinking particles of a reactive polyamideimide oligomer or a composition thereof with a laser to form an article. Articles manufactured by selective laser sintering are also disclosed. Selective laser sintering (SLS) involves using a high-power laser (such as a carbon dioxide laser) to melt small particles of plastic, metal, ceramic, or glass powder into a material having a desired three-dimensional shape. The laser selectively melts the powdered material by scanning cross-sections generated from a 3D digital description of the part on the surface of the powder bed (such as from a CAD file or scan data). After each cross-section is scanned, the powder bed is lowered by one layer thickness, and then a new layer of material is applied on top, and the process is repeated until the part is complete. The SLS machine preheats the bulk powder material in the powder bed to a temperature below the powder flow point to make it easier for the laser to raise the temperature of the selected area to a temperature at which the powder softens and fuses together.

[0093] In some embodiments of additive manufacturing, the manufacturing method is directed energy deposition (DED) or laser engineered net shaping (LENS). The present invention also discloses articles manufactured by DED and LENS.

[0094] Compared with some other additive manufacturing processes (such as stereolithography (SLA) and fused filament fabrication (FFF)) that most often require special support structures to manufacture overhanging designs, SLS does not require a separate feeder for support material because the part being built is always surrounded by unsintered powder, which allows the construction of geometries that were previously impossible. Additionally, since the chamber of the machine is always filled with powder material, the manufacturing of multiple parts has a much smaller impact on the overall difficulty and cost of the design because, through a technique called "nesting", multiple parts can be positioned to fit within the boundaries of the machine.

[0095] In additive manufacturing methods such as FFF and SLS that use reactive polyamideimide oligomers as raw materials, the oligomers diffuse through the particle or filament interface and interact to rapidly increase the entanglement of polymer chains at the particle or filament interface, thereby fusing adjacent particles or filaments together. The interfacial strength is further enhanced by the chain extension and crosslinking of reactive polyamideimide oligomers that wind across the interface.

[0096] Figure 2 A through 2D further illustrate the concepts of cross-interface diffusion and cross-interface chain entanglement and crosslinking. In Figure 2 each of A and 2D, the oligomer or polymer on the left is in a solid state, and the oligomer or polymer on the right is in a molten state. Figure 2 A depicts high molecular weight high performance thermoplastics on either side of the interface. The high molecular weight polymer can diffuse through the interface in both directions and form Figure 2The chain entanglements depicted in B. However, at a temperature higher than T g but lower than T m a longer thermal annealing time (in hours) is required.

[0097] Figure 2 C depicts the reactive oligomers on either side of the interface. The low molecular weight reactive oligomers diffuse faster across the interface in both directions at a temperature higher than T g but lower than T m and form the chain entanglements depicted in Figure 2 D. This rapid diffusion results in a reduction in the thermal annealing time. Chain extension and crosslinking can also occur through unreacted functional groups. The net effect of faster diffusion, chain entanglements, and chain extension and crosslinking is an increase in the interlayer strength, i.e., an increase in the z-axis strength in FFF and SLS.

[0098] As in fused filament fabrication, in selective laser sintering, the process of chain entanglement, network formation, chain extension, and crosslinking can be further enhanced by using reactive polyamideimide oligomers having two different reactive end groups. Oligomer chains containing a first unreacted functional group having a first curing temperature can be crosslinked first to fix the printed structure in place. Oligomer chains containing a second unreacted functional group having a second curing temperature higher than the first curing temperature can diffuse across the interface and cure at the second curing temperature, forming the molecular weight, crosslink density, and strength of the part.

[0099] The manufacturing method can be solution casting. Solution casting includes: casting a solution of a reactive polyamideimide oligomer dissolved in a polar solvent onto a mold; removing the polar solvent to form a reactive polyamideimide oligomer film; and heating the reactive polyamideimide oligomer film at a temperature and for a time sufficient to crosslink the polyamideimide oligomer and form a flexible film. A flexible film prepared by solution casting of a reactive polyamideimide oligomer is also disclosed.

[0100] The manufacturing method can also be injection molding. An article manufactured by injection molding a reactive polyamideimide oligomer is also disclosed.

[0101] As described above, the reactive polyamide amic acid oligomer is an intermediate for producing a reactive polyamide amino oligomer. Accordingly, the reactive polyamide amic acid oligomer comprises units derived from at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or a functional equivalent thereof, and at least one crosslinkable monomer or crosslinkable capping agent, wherein the crosslinkable monomer or crosslinkable capping agent is reactive with the at least one aromatic diamine or the at least one di-, tri- or tetra-functional aromatic carboxylic acid or a functional equivalent thereof, and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive polyamide amic acid oligomer; wherein the reactive polyamide amic acid oligomer has a number average molecular weight (M n ) of from about 1000 to about 10000 g / mol as calculated using the Carothers equation. The reactive polyamide imide oligomer and the reactive polyamide amic acid oligomer are closely related because the reactive polyamide amic acid oligomer is an intermediate for forming the corresponding reactive polyamide amine oligomer. They only differ in the degree of imidization. While the reactive polyamide imide oligomer as defined herein may have greater than 20% and less than or equal to 100% amic acid groups in the imidized reactive polyamide imidic acid intermediate, in the reactive polyamide imidic acid oligomer as defined herein, 0% to about 20% of the imidic acid groups are imidized.

[0102] The composition description applicable to the reactive polyamide imide oligomer disclosed herein is equally applicable to the reactive polyamide amic acid oligomer. Accordingly, the aromatic diamine may be at least one of 1,3-phenylenediamine, 4,4'-oxydianiline or 3,4'-oxydianiline, and the di-, tri- or tetra-functional aromatic carboxylic acid or a functional equivalent thereof may be trimellitic anhydride, 4-chlorophthalic anhydride, isophthalic anhydride, isophthaloyl chloride, pyromellitic dianhydride or biphenyltetracarboxylic dianhydride. The unreacted functional groups participating in subsequent chain extension, branching and crosslinking reactions may be at least one of acetylene, methylacetylene, phenylacetylene, ketoacetylene, propargyl ether, norbornene, maleimide, cyanate ester, phthalonitrile, benzocyclobutene, biphenyl or benzoxazine. Table 1 gives the chemical formulas, chemical names and curing temperature ranges of these unreacted functional groups. The at least one crosslinkable monomer or crosslinkable capping agent may be two crosslinkable monomers or crosslinkable capping agents having reactivity in different temperature ranges. In some embodiments, the crosslinkable monomer or crosslinkable capping agent is at least one of 4-ethynylphthalic anhydride, 4-methyl ethynylphthalic anhydride, 4-phenyl ethynylphthalic anhydride (PEPA) or 4,4'(ethyne-1,2-diyl) diphthalic anhydride.

[0103] The reactive polyamide acid oligomer may further comprise units derived from at least one non-crosslinking capping agent, wherein the non-crosslinking capping agent is reactive with at least one aromatic diamine or at least one di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent, but does not have unreacted functional groups capable of chain extension and crosslinking after the formation of the reactive polyamide-imide oligomer. The non-crosslinking capping agent may be at least one of benzoic acid, benzoyl chloride, phthalic anhydride or aniline.

[0104] The reactive polyamide acid oligomer can be manufactured by the following method: in the presence of a polar solvent, copolymerize at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or its functional equivalent, and at least one crosslinkable monomer or crosslinkable capping agent to form a reactive polyamide acid; wherein, the crosslinkable monomer or crosslinkable capping agent is reactive with the at least one aromatic diamine or the at least one di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent, and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive polyamide acid oligomer.

[0105] The reactive polyamide acid oligomer is manufactured in the presence of a polar solvent, and the polar solvent reduces the temperature range sufficiently to prepare the reactive oligomer. The boiling point of the polar solvent at one atmosphere should be at least 150 °C. The polar solvent may be at least one of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, 1,2-dichlorobenzene, 1,2,4-trichlorobenzene or sulfolane. In some embodiments, the polar solvent is N-methyl-2-pyrrolidone. In some embodiments, the method further includes separating the reactive polyamide acid oligomer from the polar solvent.

[0106] Like the related reactive polyamide amine oligomer, the reactive polyamide acid oligomer can be used to prepare various functional materials with useful properties. Accordingly, the mixture composition comprises a reactive polyamide acid oligomer and a thermoplastic polymer. For example, the reactive polyamide acid oligomer can be used as a plasticizer or reactive diluent to improve the processability of high molecular weight PAI polymers and other high molecular weight polymers. Compared with high molecular weight PAI, the reactive oligomer added to the PAI polymer can shorten the compression molding cycle by improving fluidity and improving consolidation (minimizing voids).

[0107] Other examples of functional materials comprising the reactive polyamide acid oligomer include powder coating compositions, reactive adhesive compositions and high temperature foams.

[0108] It may be necessary to compound the reactive polyamide amic acid oligomer with other materials. Methods of blending reactive polyamide-amic acid oligomers include mixing the reactive polyamide-amic acid oligomer with at least one other material at a temperature and for a time sufficient to melt but not crosslink the reactive polyamide-amic acid oligomer. The material can be at least one polymer, filler, or additive.

[0109] Like the reactive polyamide amide oligomers, reactive polyamide amic acid oligomers can be used to make a variety of articles or components having useful properties. Thus, methods of making an article include heating the reactive polyamide amic acid oligomer at a temperature and for a time sufficient to imidize, shape, and crosslink the reactive polyamide amic acid oligomer. The temperature and time sufficient to imidize, shape, and crosslink the reactive polyamide amic acid oligomer are about 1 to about 60 minutes at about 300 to about 450 °C. Exemplary curing conditions are about 30 to about 60 minutes at about 350 to about 400 °C, such as about 45 minutes at about 360 °C.

[0110] For example, the method of making can be additive manufacturing, fiber-reinforced composite manufacturing, pultrusion, fiber spinning, compression molding, injection molding, reaction injection molding, blow molding, rotational molding, transfer molding, foam molding, thermoforming, casting, solution casting, or forging.

[0111] Articles made by this method are also disclosed. Various methods of making and articles made by this method are described below.

[0112] The method of making can be fiber-reinforced composite manufacturing. The reactive polyamide amic acid oligomer can be in the form of a powder or a film. Thus, fiber-reinforced composite manufacturing can include heating at least one layer of fiber fabric and at least one layer of reactive polyamide amic acid oligomer in the form of a powder or a film at a temperature, pressure, and time sufficient to imidize the reactive polyamide amic acid oligomer, impregnating the fiber fabric, and crosslinking to form a fiber-reinforced composite.

[0113] The reactive polyamide amic acid oligomer can also be dissolved in a polar solvent. Thus, the fiber-reinforced manufacturing method can include: impregnating at least one layer of fiber fabric with a solution of the reactive polyamide amic acid oligomer dissolved in a polar solvent; removing the polar solvent under reduced pressure, and heating at a temperature, pressure, and time sufficient to imidize and crosslink the reactive polyamide amic acid oligomer to form a fiber-reinforced composite. For example, the fiber can be carbon fiber, glass fiber, cellulose (wood fiber / paper fiber, straw), polyamine (poly-p-phenylene terephthalamide), polybenzoxazole (PBO), or polybenzimidazole (PBI).

[0114] The present invention also discloses a fiber-reinforced composite material, which is made from a reactive polyamide amic acid oligomer by any of the above methods. For example, the composite material can be a multi-layer carbon-reinforced composite material. The multi-layer reinforced composite material can have any number of layers, but in some embodiments, the number of layers is greater than or equal to 2 and less than or equal to 1000 layers.

[0115] The manufacturing method can be pultrusion, which is used to make unidirectional tapes. Similar to the manufacturing of fiber-reinforced composite materials, pultrusion can be from a melt or solution of a reactive polyamide amic acid oligomer in a polar solvent. Unidirectional tapes prepared by pultrusion are also disclosed. The unidirectional (UD) tape can be a plain tape, a slit tape, a roving, or a tow tape. The UD tape can be used in tape laying technology / TOW robots for manufacturing fiber-reinforced composite materials.

[0116] The manufacturing method can be solution spinning or melt spinning of fibers of a reactive polyamide amic acid oligomer. Fibers manufactured by solution spinning or melt spinning of a reactive polyamide amic acid oligomer are also disclosed.

[0117] The manufacturing method can be additive manufacturing. The present invention also discloses articles made by additive manufacturing. In some embodiments of additive manufacturing, the method is fused filament fabrication. Fused filament fabrication includes extruding a reactive polyamide amide amic acid oligomer in adjacent horizontal layers such that there is an interface between each layer of the reactive polyamide amide amic acid oligomer, and exposing each layer to heat at a temperature and for a time sufficient to imidize and crosslink the reactive polyamide amic acid oligomer and form the article. Articles made by fused filament fabrication of a reactive polyamide amic acid oligomer are also disclosed.

[0118] In some embodiments of additive manufacturing, the method is selective laser sintering. Selective laser sintering includes selectively sintering, imidizing, and crosslinking reactive polyamide amic acid oligomer particles with a laser to form an article. Articles made by selective laser sintering of a reactive polyamide amic acid oligomer are also disclosed.

[0119] In some embodiments of additive manufacturing, the manufacturing method is directed energy deposition (DED) or laser engineered net shaping (LENS). Articles made by DED and LENS of a reactive polyamide amic acid oligomer are also disclosed.

[0120] The manufacturing method can be solution casting. Solution casting includes: casting a solution of a reactive polyamide amic acid oligomer dissolved in a polar solvent onto a mold; removing the solvent to form a reactive polyamide amic acid oligomer film; and heating the reactive polyamide amic acid oligomer film at a temperature and for a time sufficient to imidize and crosslink the reactive polyamide amic acid oligomer and form a flexible film. Flexible films prepared by solution casting of a reactive polyamide amic acid oligomer are also disclosed.

[0121] The manufacturing method can also be injection molding. Articles made by injection molding reactive polyamide amic acid oligomers are also disclosed.

[0122] The manufacturing method can also be blow molding. The present invention also discloses articles made by blow molding reactive polyamide amic acid oligomers.

[0123] The "ammonium carboxylate salt" method for manufacturing reactive polyamide imide oligomers was discussed above. The first step of this method is to form a reactive ammonium carboxylate salt. As an intermediate for manufacturing reactive polyamide imide oligomers, the reactive ammonium carboxylate salt itself is a useful composition. Therefore, a reactive ammonium carboxylate salt formed by the following method is disclosed herein: in the presence of C 1-4 alcohol, heating at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or its functional equivalent, and at least one crosslinkable monomer or crosslinkable capping agent at a temperature and for a time sufficient to form the reactive ammonium carboxylate salt, such as about 50 °C to about 150 °C for about 30 minutes to about 8 hours; removing the excess C 1-4 alcohol; wherein the crosslinkable monomer or crosslinkable capping agent is reactive with the at least one aromatic diamine or the at least one di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent, and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive ammonium carboxylate salt. For example, C 1-4 alcohol can be at least one of methanol, ethanol, 1-propanol, isopropanol, 1-butanol, isobutanol, sec-butanol or tert-butanol. In some embodiments, C 1-4 alcohol is at least one of methanol or ethanol.

[0124] The reactive ammonium carboxylates are related to the reactive polyamideimide oligomers and reactive polyamide amic acid oligomers disclosed herein in that they can all be made from the same at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or its functional equivalent, and at least one self-reactive monomer or capping agent. Accordingly, the compositional descriptions applicable to the reactive polyamideimide oligomers and reactive polyamide amic acid oligomers disclosed herein are equally applicable to the reactive ammonium carboxylates, except that aromatic acid chlorides are not necessary. Thus, the aromatic diamine can be at least one of 1,3-benzenediamine, 4,4'-oxydianiline or 3,4'-oxydianiline, and the di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent can be at least one of trimellitic anhydride, isophthalic anhydride, pyromellitic dianhydride or biphenyltetracarboxylic dianhydride. The unreacted functional groups participating in subsequent chain extension, branching and crosslinking reactions can be at least one of acetylene, methylacetylene, phenylacetylene, ketoacetylene, propargyl ether, norbornene, maleimide, cyanate ester, phthalonitrile, benzocyclobutene, biphenyl or benzoxazine. Table 1 gives the chemical formulas, chemical names and curing temperature ranges of these unreacted functional groups. The at least one crosslinkable monomer or crosslinkable capping agent can be two crosslinkable monomers or crosslinkable capping agents that are reactive in different temperature ranges. In some embodiments, the crosslinkable monomer or crosslinkable capping agent is at least one of 4-ethynylphthalic anhydride, 4-methyl-ethynylphthalic anhydride, 4-phenyl-ethynylphthalic anhydride (PEPA) or 4,4'-(ethyne-1,2-diyl)diphthalic anhydride.

[0125] The reactive ammonium carboxylates can also contain units derived from at least one non-crosslinking capping agent, where the non-crosslinking capping agent is reactive with at least one aromatic diamine or at least one di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent, but does not have unreacted functional groups capable of chain extension and crosslinking after the formation of the reactive polyamideimide oligomers. The non-crosslinking capping agent can be at least one of benzoic acid, benzoyl chloride, phthalic anhydride or aniline.

[0126] Advantageously, the reactive ammonium carboxylates can have a melt complex viscosity of about 1 to about 100 Pa·s between about 80 °C and about 120 °C, measured by oscillatory shear rheology between parallel plates at a heating rate of 10 °C / min, a frequency of 2 radians / second and a strain of 0.03%-1.0% under N 2 . Within this range, the melt complex viscosity is a function of M n and the type and relative amounts of at least one diamine present, at least one di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent, crosslinkable or non-crosslinkable monomers and capping agents. Depending on the preparation method, the reactive ammonium carboxylates can also melt at about 320 °C.

[0127] The method for manufacturing the reactive ammonium carboxylates includes: in water or C1-4 Heating at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or a functional equivalent thereof, and at least one crosslinkable monomer or crosslinkable capping agent in the presence of at least one alcohol at a temperature and for a time sufficient to form a reactive ammonium carboxylate salt; and removing excess C 1-4 alcohol; wherein the crosslinkable monomer or crosslinkable capping agent is reactive with the at least one aromatic diamine or the at least one di-, tri- or tetra-functional aromatic carboxylic acid or a functional equivalent thereof, and has at least one unreacted functional group capable of chain extension and crosslinking after formation of the reactive ammonium carboxylate salt.

[0128] Like the reactive polyamideimide oligomer and the reactive polyamide acid oligomer, it is necessary to compound the reactive ammonium carboxylate salt with other materials. The method of blending the reactive polyamide-acid oligomer includes mixing the reactive polyamide-acid oligomer with at least one other material at a temperature and for a time sufficient to melt but not crosslink the reactive polyamide-acid oligomer. The material can be at least one polymer, filler or additive.

[0129] Like the reactive polyamideimide oligomer and the reactive polyamide acid oligomer, the reactive ammonium carboxylate salt can be used to manufacture various articles or components having useful properties. Therefore, the manufacturing method of the article includes heating the reactive ammonium carboxylate salt at a temperature, pressure and time sufficient to prepare, shape and crosslink the reactive polyamideimide oligomer. The temperature and time sufficient to prepare, shape and crosslink the reactive polyamide acid oligomer are about 300 °C to about 400 °C, 0 to about 300 MPa, and about 10 to about 60 minutes.

[0130] For example, the manufacturing method can be fiber-reinforced composite material manufacturing, pultrusion, compression molding, injection molding or solution casting. Articles manufactured by this method are also disclosed. The manufacturing method and the articles manufactured by this method are described below.

[0131] The manufacturing method can be fiber-reinforced composite material manufacturing. The active ammonium carboxylate salt can exist in the form of a powder or a film. Therefore, the fiber-reinforced composite material manufacturing can include heating at least one layer of fiber fabric and at least one layer of active ammonium carboxylate salt in the form of a powder or a film at a temperature, pressure and time sufficient to impregnate the fiber fabric with the active ammonium carboxylate salt and to prepare and crosslink the reactive polyamideimide oligomer to form a fiber-reinforced composite material.

[0132] The reactive ammonium carboxylate salts can also be dissolved in polar solvents. Accordingly, the fiber reinforcement manufacturing method can include impregnating a fiber fabric with a solution of a reactive ammonium carboxylate salt dissolved in a polar solvent; removing the polar solvent under reduced pressure; and heating at a temperature, pressure, and time sufficient to polymerize and crosslink the reactive polyamideimide oligomers to form a fiber-reinforced composite material. For example, the fibers can be carbon fibers, glass fibers, cellulose (wood fiber / paper fiber, straw), polyamine (poly-p-phenylene terephthalamide), polybenzoxazole (PBO), or polybenzimidazole (PBI).

[0133] Also disclosed is a fiber-reinforced composite material made from a reactive ammonium carboxylate salt by any of the above methods. For example, the composite material can be a multi-layer carbon-reinforced composite material. The multi-layer reinforced composite material can have any number of layers, but in some embodiments, the number of layers is greater than or equal to 2 and less than or equal to 1000 layers.

[0134] The manufacturing method can be solution casting. Solution casting includes: casting a solution of a reactive ammonium carboxylate salt dissolved in a polar solvent onto a mold; removing the polar solvent to form a reactive ammonium carboxylate salt film; and heating the reactive ammonium carboxylate salt film at a temperature, pressure, and time sufficient to prepare and crosslink the reactive polyamideimide oligomers to form a flexible film. Also disclosed is a flexible film prepared by solution casting of a reactive ammonium carboxylate salt solution.

[0135] The manufacturing method can also be injection molding of the reactive ammonium carboxylate salt. Also disclosed are articles made by injection molding of the reactive ammonium carboxylate salt. The manufacturing method can also be compression molding of the reactive ammonium carboxylate salt. The present invention also discloses articles made by compression molding of the reactive ammonium carboxylate salt.

[0136] Reactive polyamideimide oligomers and reactive polyamideamic acid oligomers (“reactive oligomers”), manufacturing methods using the reactive oligomers, and articles made from the reactive oligomers have several advantageous properties. Currently available high molecular weight PAI can have a relatively high level of amic acid groups in order to have a complex viscosity low enough to be melt processable. The presence of amic acid groups can make the PAI highly hygroscopic. Accordingly, preprocessing drying is also required. As Figure 1The fabrication and processing of currently available PAI of the shown construction involves the imidization of polyamide acid profiles or injection molded parts and requires long thermal post-treatment to remove the water generated from the conversion of amide acid groups to imide groups. The processed PAI parts are also exposed to a multi-day heat treatment schedule after processing. The general cure schedule recommended by manufacturers is: 375°F (191°C) for 1 day, 425°F (218°C) for 1 day, 475°F (246°C) for 1 day, and 500°F (260°C) for 5 days, for a total of 8 days. In contrast, the cure of reactive polyamideimide oligomers at about 300 to about 450 °C can be completed in as short as about 1 to about 60 minutes. Advantageously, this reduction in thermal post-treatment time results in a significant reduction in manufacturing cycle time and cost.

[0137] Reactive polyamideimide oligomers having an M of about 1000 to about 10000 g / mol n The reactive polyamideimide oligomers advantageously exhibit a complex melt viscosity of about 1000 to about 100000 Pa·s at 360 °C, particularly about 5000 to about 30000 Pa·s at 360 °C. In contrast, currently available PAI is reported to have a complex melt viscosity of about 1000000 Pa·s at 2 radians / second. The low complex melt viscosity of the fully imidized reactive polyamideimide oligomers relative to currently available PAI is unexpected. Compared to the low complex melt viscosity obtained, the alternating combination of rigid backbone phthalimide units with aromatic amide units that are expected to form strong hydrogen bonds as in polyaramides would be expected to result in a high melting point and high complex melt viscosity even for reactive polyamideimide oligomers. Advantageously, when the complex melt viscosity is in the range of about 1000 to about 100000 Pa·s at 360 °C, melt processing can be carried out using conventional melt processing equipment and ready-to-use injection molded parts, films, fibers, and melt processable high temperature adhesives can be made. In addition, compared to polyamide acid polymers, the fully imidized reactive polyamideimide oligomers have lower hygroscopicity than polyamide acid polymers and are insoluble in polar solvents such as DMF, NMP, and DMAc depending on the monomers used and the reactive and non-reactive end-capping agents.

[0138] Advantageously, the thermal cure temperature range and the thermomechanical properties after cure can be controlled by selecting the backbone monomers, crosslinkable monomers, crosslinkable end-capping agents, and non-crosslinkable end-capping agents. In addition, improved thermomechanical properties are obtained using the reactive polyamideimide oligomers of the present invention. Referring to Example 1C below, it is a reactive polyamideimide oligomer with an M n of 5000 g / mol, where both reactive end groups are phenylacetylene. The T of a film made from the reactive polyamideimide oligomer and cured at 370 °C for 1 hour g is 326 °C, which is higher than the T of currently available PAI filmsg It is about 46 °C. Also refer to Example 2 below, which is a reactive polyamideimide oligomer having M of 5000 g / mol n and a mixed reactive end group (50 / 50 methylacetylene / phenylethylene). The T of the film made from the reactive polyamideimide oligomer and cured at 370 °C for 1 hour g is 301 °C. The toughness of the film is 94.3 MJ / m 3 . In contrast, the toughness of currently available PAI is only about 10 MJ / m 3 . Therefore, the toughness of the PAI film made from this reactive polyamideimide oligomer is almost 10 times that of the PAI made from currently available PAI. Compared with currently available PAI, T g , breaking strength and elongation at break are also improved.

[0139] Advantageously, the low melt complex viscosity of the reactive polyamideimide oligomer relative to the high molecular weight polyamideimide polymer makes the reactive polyamideimide oligomer ideally suitable for preparing fiber-reinforced composites, such as glass, carbon and aramid fiber-reinforced composites.

[0140] Solution-based pre-impregnation, melt impregnation and melt pultrusion methods can all be used. High molecular weight polyamide amic acid can be used to prepare fiber / resin prepregs and composites. However, it is difficult to obtain sufficient melt flow to melt and solidify the polyamide amic acid prepreg into a composite panel. In addition, during the imidization process of polyamide amic acid, it may be difficult to remove water from the composite panel. This means that it is difficult to achieve voids below 2%, which is considered acceptable. Alternatively, the high molecular weight polyamide amic acid can be converted into high molecular weight polyamideimide at the pre-impregnation stage, and the polyamideimide prepreg can be solidified into a composite material. The even higher melt complex viscosity of high molecular weight polyamideimide will make it difficult to obtain sufficient melt flow under pressure to solidify the prepreg into a composite panel with acceptable quality. Therefore, the relatively low melt complex viscosity of the reactive polyamideimide oligomer provides advantages over both high molecular weight polyamideimide and high molecular weight polyamide amic acid in the manufacture of fiber-reinforced composites.

[0141] Compared with high molecular weight polyamideimide polymers, the low melt complex viscosity of reactive polyamideimide oligomers also makes them ideally suitable for 3D printing applications. The reactive polyamideimide oligomers can be used in the form of filaments, rods or powders.

[0142] The present disclosure is further illustrated by the following aspects of the present disclosure, which are not intended to limit the claims.

[0143] Embodiments based on the current claims

[0144] Aspect 1. A reactive polyamideimide oligomer comprising units derived from at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or a functional equivalent thereof, and at least one crosslinkable monomer or crosslinkable capping agent; wherein the crosslinkable monomer or crosslinkable capping agent is reactive with the at least one aromatic diamine or at least one di-, tri- or tetra-functional aromatic carboxylic acid or a functional equivalent thereof and has at least one unreacted functional group capable of undergoing thermal chain extension and crosslinking after the formation of the reactive polyamideimide oligomer; and wherein the number average molecular weight (M n ) calculated using the Carothers equation is from about 1000 to about 10000 g / mol.

[0145] Aspect 2. The reactive polyamideimide oligomer according to Aspect 1, wherein the reactive polyamideimide oligomer is derived from a reactive polyamideamic acid oligomer intermediate by dehydration cyclization, and more than 80% and less than or equal to 100% of the amic acid groups in the reactive polyamideamic acid intermediate are imidized.

[0146] Aspect 3. The reactive polyamideimide oligomer according to Aspect 1, wherein the reactive polyamideimide oligomer is derived from a reactive polyamideamic acid oligomer intermediate by dehydration cyclization, and more than or equal to 20% and less than or equal to 80% of the amic acid groups in the reactive polyamideamic acid intermediate are imidized.

[0147] Aspect 4. The reactive polyamideimide oligomer according to any one of Aspects 1 to 3, wherein the crosslinkable monomer or crosslinkable capping agent has one unreacted functional group capable of undergoing thermal chain extension and crosslinking after the formation of the reactive polyamideimide oligomer.

[0148] Aspect 5. The reactive polyamideimide oligomer according to any one of Aspects 1 to 4, wherein the at least one crosslinkable monomer or crosslinkable capping agent is at least one crosslinkable capping agent.

[0149] Aspect 6. The reactive polyamideimide oligomer according to any one of Aspects 1 to 5, wherein the at least one aromatic diamine is two aromatic diamines.

[0150] Aspect 7. The reactive polyamideimide oligomer according to any one of Aspects 1 to 6, wherein the at least one aromatic di-, tri- or tetra-functional carboxylic acid or a functional equivalent thereof is two aromatic di-, tri- or tetra-functional carboxylic acids or a functional equivalent thereof.

[0151] Aspect 8. The reactive polyamideimide oligomer according to any one of Aspects 1 to 7, which is prepared by a method comprising: simultaneously stepwise polymerizing at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or its functional equivalent, and at least one crosslinkable monomer or crosslinkable end-capping agent.

[0152] Aspect 9. The reactive polyamideimide oligomer according to any one of Aspects 1 to 8, wherein the aromatic diamine is at least one of the following:

[0153]

[0154] Aspect 10. The reactive polyamideimide oligomer according to any one of Aspects 1 to 9, wherein the aromatic diamine is at least one of 1,3-phenylenediamine, 4,4'-oxydianiline, and 3,4'-oxydianiline.

[0155] Aspect 11. The reactive polyamideimide oligomer according to any one of Aspects 1 to 10, wherein the di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent is at least one of the following:

[0156]

[0157] Aspect 12. The reactive polyamideimide oligomer according to any one of Aspects 1 to 11, wherein the di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent is at least one of trimellitic anhydride, 4-chlorocarbonyl phthalic anhydride, isophthalic anhydride, isophthaloyl chloride, pyromellitic dianhydride, or biphenyltetracarboxylic dianhydride.

[0158] Aspect 13. The reactive polyamideimide oligomer according to any one of Aspects 1 to 12, wherein the unreacted functional group is at least one of acetylene, methylacetylene, phenylacetylene, ketoacetylene, propargyl ether, norbornene, maleimide, cyanate ester, phthalonitrile, benzocyclobutene, biphenyl, or benzoxazine.

[0159] Aspect 14. The reactive polyamideimide oligomer according to any one of Aspects 1 to 13, wherein the crosslinkable monomer or crosslinkable end-capping agent is at least one of the following:

[0160]

[0161]

[0162] Aspect 15. The reactive polyamideimide oligomer according to any one of Aspects 1 to 14, wherein the crosslinkable monomer or crosslinkable capping agent is at least one of 4-ethynylphthalic anhydride, 4-methylethynylphthalic anhydride, 4-phenylethynylphthalic anhydride (PEPA), or 4,4'-(ethyne-1,2-diyl)diphthalic anhydride.

[0163] Aspect 16. The reactive polyamideimide oligomer according to any one of Aspects 1 to 15, which comprises two crosslinkable monomers or crosslinkable capping agents that are reactive in different temperature ranges.

[0164] Aspect 17. The reactive polyamideimide oligomer according to any one of Aspects 1 to 16, which further comprises units derived from at least one non-crosslinkable capping agent, wherein the non-crosslinkable capping agent is reactive with the at least one aromatic diamine or at least one di-, tri-, or tetra-functional aromatic carboxylic acid or its functional equivalent.

[0165] Aspect 18. The reactive polyamideimide oligomer according to Aspect 17, wherein the non-crosslinkable capping agent is at least one of benzoic acid, benzoyl chloride, phthalic anhydride, or aniline.

[0166] Aspect 19. The reactive polyamideimide oligomer according to any one of Aspects 1 to 18, which further comprises units derived from at least one of an aromatic triamine, an aromatic tricarboxylic acid, or an aromatic tricarboxylic acid chloride.

[0167] Aspect 20. The reactive polyamideimide oligomer according to any one of Aspects 1 to 19, wherein the melt complex viscosity of the reactive polyamideimide oligomer at 360 °C is about 1000 to about 100000 Pa·s, and the melt complex viscosity is measured by oscillatory shear rheology between parallel plates at a heating rate of 10 °C / minute, a frequency of 2 radians / second, and a strain of 0.03% to 1.0% under N 2 at a heating rate of 10 °C / minute, a frequency of 2 radians / second, and a strain of 0.03% to 1.0% under N.

[0168] Aspect 21. A reactive polyamideimide oligomer comprising units derived from: at least one aromatic diamine selected from the following:

[0169]

[0170] at least one di-, tri-, or tetra-functional aromatic carboxylic acid or its functional equivalent selected from the following:

[0171] and at least one crosslinkable monomer or crosslinkable capping agent selected from the following:

[0172]

[0173]

[0174] Aspect 22. A reactive polyamideimide oligomer comprising units derived from: an aromatic diamine selected from at least one of 1,3-phenylenediamine, 4,4'-oxydianiline or 3,4'-oxydianiline; a di-, tri- or tetra-functional aromatic carboxylic acid or a functional equivalent thereof selected from at least one of trimellitic anhydride, 4-chlorocarbonyl phthalic anhydride, isophthalic anhydride, isophthaloyl chloride, pyromellitic dianhydride or biphenyltetracarboxylic dianhydride; and a crosslinkable monomer or crosslinkable capping agent selected from at least one of 4-ethynylphthalic anhydride, 4-methylethynylphthalic anhydride, 4-phenylethynylphthalic anhydride (PEPA) or 4,4'-(ethyne-1,2-diyl)diphthalic anhydride.

[0175] Aspect 23. A method of making a reactive polyamideimide oligomer according to any one of Aspects 1 to 22, the method comprising: copolymerizing at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or a functional equivalent thereof, and at least one crosslinkable monomer or crosslinkable capping agent in the presence of a polar solvent to form a reactive polyamideamic acid oligomer; and heating the reactive polyamideamic acid oligomer at a sufficient temperature and for a sufficient time to prepare the reactive polyamideimide oligomer; wherein the crosslinkable monomer or crosslinkable capping agent is reactive with the at least one aromatic diamine or the at least one di-, tri- or tetra-functional aromatic carboxylic acid or a functional equivalent thereof and has at least one unreacted functional group capable of chain extension and crosslinking after formation of the reactive polyamideimide oligomer.

[0176] Aspect 24. The method of making according to Aspect 23, wherein the sufficient temperature and time for preparing the reactive polyamideimide oligomer are about 140 °C to about 220 °C for about 1 minute to about 120 minutes.

[0177] Aspect 25. The method of making according to Aspect 23 or 24, wherein the polar solvent is at least one of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, 1,2-dichlorobenzene, 1,2,4-trichlorobenzene or sulfolane.

[0178] Aspect 26. The method of making according to any one of Aspects 23 to 25, further comprising removing the polar solvent from the polyamideamic acid oligomer before heating the reactive polyamideamic acid oligomer at a temperature and for a time sufficient to prepare the reactive polyamideimide oligomer.

[0179] Aspect 27. The manufacturing method according to Aspect 26, wherein the sufficient temperature and time for preparing the reactive polyamideimide oligomer are about 220°C to about 300°C for about 1 minute to about 120 minutes.

[0180] Aspect 28. The manufacturing method according to any one of Aspects 23 to 27, wherein the method further comprises adding toluene to the reactive polyamide amic acid oligomer and azeotropically distilling toluene and water.

[0181] Aspect 29. The manufacturing method according to any one of Aspects 23 to 27, wherein the method further comprises heating the reactive polyamide amic acid oligomer in the presence of acetic anhydride and a catalytic amount of tertiary amine.

[0182] Aspect 30. The manufacturing method according to any one of Aspects 23 to 27, wherein the method further comprises microwave irradiating the reactive polyamide amic acid oligomer.

[0183] Aspect 31. The manufacturing method according to any one of Aspects 23 to 30, wherein the copolymerization is carried out in the presence of a phosphorylating agent and a catalytic amount of salt.

[0184] Aspect 32. A method for manufacturing a reactive polyamideimide oligomer according to any one of Aspects 1 to 22, the method comprising: heating at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or its functional equivalent, and at least one crosslinkable monomer or crosslinkable capping agent in the presence of at least one water or C 1-4 alcohol at a sufficient temperature and time to form at least one reactive ammonium carboxylate salt; optionally removing excess water or C 1-4 alcohol; and heating the reactive ammonium carboxylate salt at a sufficient temperature and time to form the reactive polyamideimide oligomer; wherein the crosslinkable monomer or crosslinkable capping agent is reactive with the at least one aromatic diamine or the at least one di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive polyamideimide oligomer.

[0185] Aspect 33. The method according to Aspect 32, the method comprising reactive extrusion of the reactive ammonium carboxylate salt at a sufficient temperature and time to form the reactive polyamideimide oligomer.

[0186] Aspect 34. The method according to Aspect 32, the method comprising dissolving the reactive ammonium carboxylate salt in a polar solvent and then heating at a sufficient temperature, pressure and time to form the reactive polyamideimide oligomer.

[0187] Aspect 35. A method of manufacturing a reactive polyamideimide oligomer according to any one of Aspects 1 to 22, the method comprising reactive extrusion of at least one aromatic diamine or its activated derivative, at least one aromatic di-, tri- or tetra-functional carboxylic acid or its functional equivalent, and at least one crosslinkable monomer or crosslinkable capping agent at a sufficient temperature and for a sufficient time to prepare the reactive polyamideimide oligomer; wherein the crosslinkable monomer or crosslinkable capping agent is reactive with at least one aromatic diamine or at least one di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent, and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive polyamideimide oligomer.

[0188] Aspect 36. The manufacturing method according to Aspect 35, wherein the reactive extrusion is carried out in the presence of a polar solvent, and the polar solvent is removed by distillation during the reactive extrusion.

[0189] Aspect 37. The manufacturing method according to Aspect 35 or 36, wherein the reactive extrusion is carried out in the presence of an acidic catalyst.

[0190] Aspect 38. The manufacturing method according to Aspect 37, wherein the acidic catalyst is acetic acid, and the acetic acid is removed by distillation during the reactive extrusion.

[0191] Aspect 39. The manufacturing method according to any one of Aspects 35 to 38, wherein the reactive extrusion is carried out in the presence of acetic anhydride, and the acetic anhydride is removed by distillation during the reactive extrusion.

[0192] Aspect 40. The manufacturing method according to any one of Aspects 35 to 39, wherein the reactive extrusion is carried out in a melt extruder having a plurality of preset heating zones equipped with vents.

[0193] Aspect 41. A blend composition comprising a reactive polyamideimide oligomer according to any one of Aspects 1 to 22 and a thermoplastic polymer.

[0194] Aspect 42. A powder coating composition comprising a reactive polyamideimide oligomer according to any one of Aspects 1 to 22.

[0195] Aspect 43. A reactive adhesive composition comprising a reactive polyamideimide oligomer according to any one of Aspects 1 to 22.

[0196] Aspect 44. A high-temperature elastomer composition prepared by heating a reactive polyamideimide oligomer according to any one of Aspects 1 to 22 at a temperature and for a time sufficient to crosslink the reactive polyamideimide oligomer.

[0197] Aspect 45. A high-temperature foam comprising a reactive polyamideimide oligomer according to any one of Aspects 1 to 22.

[0198] Aspect 46. A method of blending a reactive polyamideimide oligomer according to any one of Aspects 1 to 22, the method comprising mixing the reactive polyamideimide oligomer with at least one other material at a sufficient temperature and for a sufficient time to melt but not crosslink the reactive polyamideimide oligomer.

[0199] Aspect 47. A method of manufacturing an article, the method comprising heating a reactive polyamideimide oligomer according to any one of Aspects 1 to 22 at a sufficient temperature and for a sufficient time to shape and crosslink the reactive polyamideimide oligomer.

[0200] Aspect 48. The manufacturing method according to Aspect 47, wherein the sufficient temperature and time are about 300 to about 450 °C for about 1 to about 60 minutes.

[0201] Aspect 49. The manufacturing method according to Aspect 47 or 48, wherein the method is additive manufacturing, fiber-reinforced composite manufacturing, pultrusion, fiber spinning, compression molding, injection molding, reaction injection molding, blow molding, rotational molding, transfer molding, foam molding, thermoforming, casting, solution casting, or forging.

[0202] Aspect 50. An article manufactured by the method according to any one of Aspects 47 to 49.

[0203] Aspect 51. An article comprising a reactive polyamideimide oligomer according to any one of Aspects 1 to 22.

[0204] Aspect 52. The article according to Aspect 51, wherein the reactive polyamideimide oligomer is crosslinked.

[0205] Aspect 53. The manufacturing method according to any one of Aspects 47 to 49, wherein the method is fiber-reinforced composite manufacturing.

[0206] Aspect 54. The method according to Aspect 53, the method comprising heating at least one layer of fiber fabric and at least one layer of reactive polyamideimide oligomer in the form of a powder or a film at a sufficient temperature, pressure, and time to melt the reactive polyamideimide oligomer, impregnate the fiber fabric, and crosslink the reactive polyamideimide oligomer to form a fiber-reinforced composite.

[0207] Aspect 55. The method according to aspect 53, the method comprising: impregnating at least one layer of a fibrous fabric with a solution of a reactive polyamide-imide oligomer dissolved in a polar solvent; removing the polar solvent under reduced pressure; and heating at a sufficient temperature, pressure, and time to crosslink the reactive polyamide-imide oligomer and form a fiber-reinforced composite material.

[0208] Aspect 56. A fiber-reinforced composite material, which is manufactured by the method according to any one of aspects 53 to 55.

[0209] Aspect 57. A fiber-reinforced composite material, which comprises a reactive polyamide-imide oligomer according to any one of aspects 1 to 22.

[0210] Aspect 58. The fiber-reinforced composite material according to aspect 57, wherein the reactive polyamide-imide oligomer is crosslinked.

[0211] Aspect 59. The fiber-reinforced composite material according to aspect 57, wherein the composite material is a multi-layer carbon-reinforced composite material.

[0212] Aspect 60. The manufacturing method according to any one of aspects 47 to 49, wherein the method is pultrusion for manufacturing a unidirectional tape.

[0213] Aspect 61. A unidirectional tape, which is prepared by the method according to aspect 60.

[0214] Aspect 62. A unidirectional tape, which comprises a reactive polyamide-imide oligomer according to any one of aspects 1 to 22.

[0215] Aspect 63. The unidirectional tape according to aspect 62, wherein the reactive polyamide-imide oligomer is crosslinked.

[0216] Aspect 64. The manufacturing method according to any one of aspects 47 to 49, wherein the method is solution spinning or melt spinning of fibers.

[0217] Aspect 65. A fiber, which is manufactured by the method according to aspect 64.

[0218] Aspect 66. A fiber, which comprises a reactive polyamide-imide oligomer according to any one of aspects 1 to 22.

[0219] Aspect 67. The fiber according to aspect 66, wherein the reactive polyamide-imide oligomer is crosslinked.

[0220] Aspect 68. The manufacturing method according to any one of aspects 47 to 49, wherein the method is additive manufacturing.

[0221] Aspect 69. The manufacturing method according to aspect 68, wherein the method is fused deposition modeling, the method includes extruding the reactive polyamide-imide oligomer in adjacent horizontal layers such that there is an interface between each polyamide-imide oligomer layer, and exposing the layers to heat at a temperature and for a time sufficient to crosslink the reactive polyamide-imide oligomer and form a product.

[0222] Aspect 70. The manufacturing method according to aspect 68, wherein the method is selective laser sintering, the method includes selectively sintering and crosslinking the particles of the reactive polyamide-imide oligomer with a laser to form a product.

[0223] Aspect 71. The manufacturing method according to aspect 68, wherein the method is directed energy deposition (DED) or laser engineered net shaping (LENS).

[0224] Aspect 72. A product manufactured by the method according to any one of aspects 68 to 71.

[0225] Aspect 73. An additive manufacturing product, which contains the reactive polyamide-imide oligomer according to any one of aspects 1 to 22.

[0226] Aspect 74. The additive manufacturing product according to aspect 73, wherein the reactive polyamide-imide oligomer is crosslinked.

[0227] Aspect 75. The manufacturing method according to any one of aspects 47 to 49, wherein the method is solution casting and includes: casting a solution of the reactive polyamide-imide oligomer dissolved in a polar solvent onto a mold; removing the polar solvent to form a reactive polyamide-imide oligomer film; and heating the polyamide-imide oligomer film at a temperature and for a time sufficient to crosslink the polyamide-imide oligomer and form a flexible film.

[0228] Aspect 76. A flexible film manufactured by the solution casting method according to aspect 75.

[0229] Aspect 77. A flexible film, which contains the reactive polyamide-imide oligomer according to any one of aspects 1 to 22.

[0230] Aspect 78. The flexible film according to aspect 77, wherein the reactive polyamide-imide oligomer is crosslinked.

[0231] Aspect 79. The flexible film according to any one of aspects 76 to 78, wherein the flexible film exhibits at least one of the following: at N 2 under a heating rate of 10 °C / min by differential scanning calorimetry measurement, the glass transition temperature (Tg) is about 280 to about 310 °C; at N 2Measured by dynamic mechanical thermal analysis at a heating rate of 10 °C / min and an oscillation rate of 1 Hz, the storage modulus (E') is about 2.2 to about 3.4 GPa; the Young's modulus is about 3.0 to about 3.8 GPa, the fracture strength is about 130 to about 160 MPa, or the fracture strain is about 10 to 80%, all measured at 25 °C.

[0232] Aspect 80. The manufacturing method according to any one of aspects 47 to 49, wherein the method is injection molding.

[0233] Aspect 81. An injection molded article manufactured by the method according to aspect 80.

[0234] Aspect 82. An injection molded article comprising a reactive polyamideimide oligomer according to any one of aspects 1 to 22.

[0235] Aspect 83. The additive manufactured article according to aspect 82, wherein the reactive polyamideimide oligomer is crosslinked.

[0236] Aspect 84. A reactive polyamide amic acid oligomer comprising units derived from: at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or a functional equivalent thereof; and at least one crosslinkable monomer or crosslinkable capping agent, wherein the crosslinkable monomer or crosslinkable capping agent is reactive with the at least one aromatic diamine or the at least one di-, tri- or tetra-functional aromatic carboxylic acid or a functional equivalent thereof and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive polyamide amic acid oligomer; and wherein the number average molecular weight (M n ) calculated using the Carothers equation is about 1000 to about 10000 g / mol.

[0237] Aspect 85. The reactive polyamide amic acid oligomer according to aspect 84, wherein 0% to about 20% of the amic acid groups are imidized.

[0238] Aspect 86. The reactive polyamide amic acid oligomer according to aspect 84 or 85, wherein the crosslinkable monomer or crosslinkable capping agent has one unreacted functional group capable of thermal chain extension and crosslinking after the formation of the reactive polyamideimide oligomer.

[0239] Aspect 87. The reactive polyamide amic acid oligomer according to any one of aspects 84 to 86, wherein the at least one crosslinkable monomer or crosslinkable capping agent is at least one crosslinkable capping agent.

[0240] Aspect 88. The reactive polyamide amic acid oligomer according to any one of aspects 84 to 87, wherein the at least one aromatic diamine is two aromatic diamines.

[0241] Aspect 89. The reactive polyamide amic acid oligomer according to any one of Aspects 84 to 88, wherein the at least one aromatic di-, tri- or tetra-functional carboxylic acid or its functional equivalent is two aromatic di-, tri- or tetra-functional carboxylic acids or their functional equivalents.

[0242] Aspect 90. The reactive polyamide amic acid oligomer according to any one of Aspects 84 to 89, which is prepared by a method comprising simultaneously stepwise polymerizing the at least one aromatic diamine, the at least one aromatic di-, tri- or tetra-functional carboxylic acid or its functional equivalent, and the at least one crosslinkable monomer or crosslinkable capping agent.

[0243] Aspect 91. The reactive polyamide amic acid oligomer according to any one of Aspects 84 to 90, wherein the aromatic diamine is at least one of the following:

[0244]

[0245] Aspect 92. The reactive polyamide amic acid oligomer according to any one of Aspects 84 to 91, wherein the aromatic diamine is at least one of 1,3-phenylenediamine, 4,4'-oxydianiline or 3,4'-oxydianiline.

[0246] Aspect 93. The reactive polyamide amic acid oligomer according to any one of Aspects 84 to 92, wherein the di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent is at least one of the following:

[0247]

[0248] Aspect 94. The reactive polyamide amic acid oligomer according to any one of Aspects 84 to 93, wherein the di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent is at least one of trimellitic anhydride, 4-chlorocarbonyl phthalic anhydride, phthalic anhydride, isophthaloyl chloride, pyromellitic dianhydride or biphenyltetracarboxylic dianhydride.

[0249] Aspect 95. The reactive polyamide amic acid oligomer according to any one of Aspects 84 to 94, wherein the at least one unreacted functional group is at least one of acetylene, methylacetylene, phenylacetylene, ketoacetylene, propargyl ether, norbornene, maleimide, cyanate ester, phthalonitrile, benzocyclobutene, biphenyl or benzoxazine.

[0250] Aspect 96. The reactive polyamide amic acid oligomer according to any one of Aspects 84 to 95, wherein the crosslinkable monomer or crosslinkable capping agent is at least one of the following:

[0251]

[0252]

[0253] Aspect 97. A reactive polyamide amic acid oligomer according to any one of aspects 84 to 96, wherein the crosslinkable monomer or crosslinkable capping agent is at least one of 4-ethynylphthalic anhydride, 4-methylethynylphthalic anhydride, 4-phenylethynylphthalic anhydride (PEPA), or 4,4'-(ethyne-1,2-diyl) diphthalic anhydride.

[0254] Aspect 98. A reactive polyamide amic acid oligomer according to any one of aspects 84 to 97, which comprises two crosslinkable monomers or crosslinkable capping agents that are reactive in different temperature ranges.

[0255] Aspect 99. A reactive polyamide amic acid oligomer according to any one of aspects 84 to 98, which further comprises units derived from at least one non-crosslinkable capping agent, wherein the non-crosslinkable capping agent is reactive with the at least one aromatic diamine or at least one di-, tri-, or tetra-functional aromatic carboxylic acid or its functional equivalent.

[0256] Aspect 100. The reactive polyamide amic acid oligomer according to aspect 99, wherein the non-crosslinkable capping agent is at least one of benzoic acid, benzoyl chloride, phthalic anhydride, or aniline.

[0257] Aspect 101. A reactive polyamide amic acid oligomer comprising units derived from:

[0258] at least one aromatic diamine selected from the following:

[0259]

[0260] at least one di-, tri-, or tetra-functional aromatic carboxylic acid or its functional equivalent selected from the following:

[0261] and at least one crosslinkable monomer or crosslinkable capping agent selected from the following:

[0262]

[0263]

[0264] Aspect 102. A reactive polyamide acid oligomer comprising units derived from: an aromatic diamine selected from at least one of 1,3-benzenediamine, 4,4'-oxydianiline or 3,4'-oxydianiline; a di-, tri- or tetra-functional aromatic carboxylic acid or a functional equivalent thereof selected from at least one of trimellitic anhydride, 4-chlorocarbonyl phthalic anhydride, phthalic anhydride, isophthaloyl chloride, pyromellitic dianhydride or biphenyltetracarboxylic dianhydride; and a crosslinkable monomer or crosslinkable capping agent selected from at least one of 4-ethynylphthalic anhydride, 4-methylethynylphthalic anhydride, 4-phenylethynylphthalic anhydride (PEPA) or 4,4'-(ethyne-1,2-diyl)diphthalic anhydride.

[0265] Aspect 103. A method for manufacturing a reactive polyamide acid oligomer according to any one of Aspects 84 to 102, the method comprising: copolymerizing at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or a functional equivalent thereof, and at least one crosslinkable monomer or crosslinkable capping agent in the presence of a polar solvent to form the reactive polyamide acid oligomer; wherein the crosslinkable monomer or crosslinkable capping agent is reactive with the at least one aromatic diamine or the at least one di-, tri- or tetra-functional aromatic carboxylic acid or a functional equivalent thereof and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive polyamide acid oligomer.

[0266] Aspect 104. The manufacturing method according to Aspect 103, wherein the polar solvent is at least one of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, 1,2-dichlorobenzene, 1,2,4-trichlorobenzene or sulfolane.

[0267] Aspect 105. The manufacturing method according to Aspect 103 or 104, further comprising separating the reactive polyamide acid oligomer from the polar solvent.

[0268] Aspect 106. A blend composition comprising a reactive polyamide acid oligomer according to any one of Aspects 84 to 102 and a thermoplastic polymer.

[0269] Aspect 107. A powder coating composition comprising a reactive polyamide acid oligomer according to any one of Aspects 84 to 102.

[0270] Aspect 108. A reactive adhesive composition comprising a reactive polyamide acid oligomer according to any one of Aspects 84 to 102.

[0271] Aspect 109. A high-temperature foam comprising a reactive polyamide acid oligomer according to any one of Aspects 84 to 102.

[0272] Aspect 110. A method of blending a reactive polyamide amic acid oligomer according to any one of Aspects 84 to 102, comprising mixing the reactive polyamide amic acid oligomer with at least one other material at a temperature and for a time sufficient to imidize but not crosslink the reactive polyamide amic acid oligomer.

[0273] Aspect 111. A method of manufacturing an article, the method comprising heating a reactive polyamide amic acid oligomer according to any one of Aspects 84 to 102 at a sufficient temperature and for a sufficient time to imidize, shape, and crosslink the reactive polyamide amic acid oligomer.

[0274] Aspect 112. The manufacturing method according to Aspect 111, wherein the sufficient temperature and time are about 300 to about 400 °C for about 10 to about 60 minutes.

[0275] Aspect 113. The manufacturing method according to Aspect 110 or 111, wherein the method is additive manufacturing, fiber-reinforced composite manufacturing, pultrusion, fiber spinning, compression molding, injection molding, reaction injection molding, blow molding, rotational molding, transfer molding, foam molding, thermoforming, casting, solution casting, or forging.

[0276] Aspect 114. An article manufactured by the method according to any one of Aspects 111 to 113.

[0277] Aspect 115. An article comprising a reactive polyamide amic acid oligomer according to any one of Aspects 84 to 102.

[0278] Aspect 116. The manufacturing method according to any one of Aspects 111 to 113, wherein the method is fiber-reinforced composite manufacturing.

[0279] Aspect 117. The method according to Aspect 116, the method comprising heating at least one layer of fiber fabric and at least one layer of reactive polyamide amic acid oligomer in the form of a powder or film at a sufficient temperature, pressure, and time to imidize the reactive polyamide amic acid oligomer, impregnate the fiber fabric, and crosslink to form a fiber-reinforced composite.

[0280] Aspect 118. The method according to Aspect 116, the method comprising impregnating at least one layer of fiber fabric with a solution of a reactive polyamide amic acid oligomer dissolved in a polar solvent; removing the polar solvent under reduced pressure, and heating at a temperature, pressure, and time sufficient to imidize and crosslink the reactive polyamide amic acid oligomer to form a fiber-reinforced composite.

[0281] Aspect 119. A fiber-reinforced composite manufactured by the method according to any one of Aspects 116 to 118.

[0282] Aspect 120. A fiber-reinforced composite material comprising a reactive polyamide amic acid oligomer according to any one of Aspects 84 to 102.

[0283] Aspect 121. The fiber-reinforced composite material according to Aspect 120, wherein the composite material is a multi-layer carbon-reinforced composite material.

[0284] Aspect 122. The manufacturing method according to any one of Aspects 111 to 113, wherein the method is pultrusion for manufacturing a unidirectional tape.

[0285] Aspect 123. A unidirectional tape prepared by the method according to Aspect 122.

[0286] Aspect 124. A unidirectional tape comprising a reactive polyamide amic acid oligomer according to any one of Aspects 84 to 102.

[0287] Aspect 125. The manufacturing method according to any one of Aspects 111 to 113, wherein the method is solution spinning or melt spinning of fibers.

[0288] Aspect 126. A fiber manufactured by the method according to Aspect 125.

[0289] Aspect 127. A fiber comprising a reactive polyamide amic acid oligomer according to any one of Aspects 84 to 102.

[0290] Aspect 128. The manufacturing method according to any one of Aspects 111 to 113, wherein the method is additive manufacturing.

[0291] Aspect 129. The manufacturing method according to Aspect 128, wherein the method is fused filament fabrication, the method comprising extruding the reactive polyamide amic acid oligomer in adjacent horizontal layers such that there is an interface between each reactive polyamide amic acid oligomer layer, and exposing the layers to heat at a temperature and for a time sufficient to imidize and crosslink the reactive polyamide amic acid oligomer and form the article.

[0292] Aspect 130. The manufacturing method according to Aspect 128, wherein the method is selective laser sintering, the method comprising selectively sintering, imidizing and crosslinking particles of the reactive polyamide amic acid oligomer with a laser to form an article.

[0293] Aspect 131. The manufacturing method according to Aspect 128, wherein the method is directed energy deposition (DED) or laser engineered net shaping (LENS).

[0294] Aspect 132. An article manufactured by the method according to any one of Aspects 128 to 131.

[0295] Aspect 133. An additive manufacturing article comprising a reactive polyamide amic acid oligomer according to any one of Aspects 84 to 102.

[0296] Aspect 134. A manufacturing method according to any one of Aspects 111 to 113, wherein the method is solution casting and comprises: casting a solution of a reactive polyamide amic acid oligomer dissolved in a polar solvent onto a mold; removing the solvent to form a reactive polyamide amic acid oligomer film; and heating the reactive polyamide amic acid oligomer film at a temperature and for a time sufficient to imidize and crosslink the reactive polyamide amic acid oligomer and form a flexible film.

[0297] Aspect 135. A flexible film manufactured by the solution casting method according to Aspect 134.

[0298] Aspect 136. A flexible film comprising a reactive polyamide amic acid oligomer according to any one of Aspects 84 to 102.

[0299] Aspect 137. A manufacturing method according to any one of Aspects 111 to 113, wherein the method is injection molding.

[0300] Aspect 138. An injection molded article manufactured by the method according to Aspect 137.

[0301] Aspect 139. An injection molded article comprising a reactive polyamide amic acid oligomer according to any one of Aspects 84 to 102.

[0302] Aspect 140. A manufacturing method according to any one of Aspects 111 to 113, wherein the method is blow molding.

[0303] Aspect 141. A reactive carboxylic acid ammonium salt formed by a method comprising: heating at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or a functional equivalent thereof, and at least one crosslinkable monomer or crosslinkable capping agent in the presence of C 1-4 alcohol at a temperature and for a time sufficient to form the reactive carboxylic acid ammonium salt; removing the excess C 1-4 alcohol; wherein the crosslinkable monomer or crosslinkable capping agent is reactive with the at least one aromatic diamine or the at least one di-, tri- or tetra-functional aromatic carboxylic acid or a functional equivalent thereof and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive carboxylic acid ammonium salt.

[0304] Aspect 142. The reactive carboxylic acid ammonium salt according to Aspect 141, wherein the crosslinkable monomer or crosslinkable capping agent has one unreacted functional group capable of thermal chain extension and crosslinking after the formation of the reactive carboxylic acid ammonium salt.

[0305] Aspect 143. The reactive ammonium carboxylate according to Aspect 141 or 142, wherein the at least one crosslinkable monomer or crosslinkable capping agent is at least one crosslinkable capping agent.

[0306] Aspect 144. The reactive ammonium carboxylate according to any one of Aspects 141 to 143, wherein the at least one aromatic diamine is two aromatic diamines.

[0307] Aspect 145. The reactive ammonium carboxylate according to any one of Aspects 141 to 144, wherein the at least one aromatic di-, tri- or tetra-functional carboxylic acid or its functional equivalent is two aromatic di-, tri- or tetra-functional carboxylic acids or their functional equivalents.

[0308] Aspect 146. The reactive ammonium carboxylate according to any one of Aspects 141 to 145, wherein the aromatic diamine is at least one of the following:

[0309]

[0310] Aspect 147. The reactive ammonium carboxylate according to any one of Aspects 141 to 146, wherein the aromatic diamine is at least one of 1,3-benzenediamine, 4,4'-oxydianiline or 3,4'-oxydianiline.

[0311] Aspect 148. The reactive ammonium carboxylate according to any one of Aspects 141 to 147, wherein the di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent is at least one of the following:

[0312]

[0313] Aspect 149. The reactive ammonium carboxylate according to any one of Aspects 141 to 148, wherein the di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent is at least one of trimellitic anhydride, phthalic anhydride, pyromellitic dianhydride or biphenyltetracarboxylic dianhydride.

[0314] Aspect 150. The reactive ammonium carboxylate according to any one of Aspects 141 to 149, wherein the unreacted functional group is at least one of acetylene, methylacetylene, phenylacetylene, ketoacetylene, propargyl ether, norbornene, maleimide, cyanate ester, phthalonitrile, benzocyclobutene, biphenyl or benzoxazine.

[0315] Aspect 151. The reactive ammonium carboxylate according to any one of Aspects 141 to 150, wherein the crosslinkable monomer or crosslinkable capping agent is at least one of the following:

[0316]

[0317]

[0318] Aspect 152. The reactive ammonium carboxylate according to any one of Aspects 141 to 151, wherein the crosslinkable monomer or crosslinkable capping agent is at least one of 4-ethynylphthalic anhydride, 4-methyl-ethynylphthalic anhydride, 4-phenylethynylphthalic anhydride (PEPA), or 4,4'-(ethyne-1,2-diyl)diphthalic anhydride.

[0319] Aspect 153. The reactive ammonium carboxylate according to any one of Aspects 141 to 152, which comprises two crosslinkable monomers or crosslinkable capping agents that are reactive in different temperature ranges.

[0320] Aspect 154. The reactive ammonium carboxylate according to any one of Aspects 141 to 153, which further comprises units derived from at least one non-crosslinkable capping agent, wherein the non-crosslinkable capping agent is reactive with at least one aromatic diamine or at least one di-, tri-, or tetra-functional aromatic carboxylic acid or a functional equivalent thereof.

[0321] Aspect 155. The reactive ammonium carboxylate according to Aspect 154, wherein the non-crosslinkable capping agent is at least one of benzoic acid, benzoyl chloride, phthalic anhydride, or aniline.

[0322] Aspect 156. The reactive ammonium carboxylate according to any one of Aspects 141 to 155, wherein the reactive ammonium carboxylate has a melt complex viscosity of about 1 to about 100 Pa·s between about 80 °C and about 120 °C, and the viscosity is measured by oscillatory shear rheology between parallel plates at a heating rate of 10 °C / minute, a frequency of 2 radians / second, and a strain of 0.03% to 1.0% under N 2 at.

[0323] Aspect 157. A reactive ammonium carboxylate comprising units derived from:

[0324] at least one aromatic diamine selected from:

[0325]

[0326] at least one di-, tri-, or tetra-functional aromatic carboxylic acid or a functional equivalent thereof selected from:

[0327] and at least one crosslinkable monomer or crosslinkable capping agent selected from:

[0328]

[0329]

[0330] Aspect 158. A reactive ammonium carboxylate comprising units derived from: an aromatic diamine selected from at least one of 1,3-benzenediamine, 4,4'-oxydianiline or 3,4'-oxydianiline; a di-, tri- or tetra-functional aromatic carboxylic acid or a functional equivalent thereof selected from at least one of trimellitic anhydride, 4-chlorophthalic anhydride, isophthalic anhydride, isophthaloyl chloride, pyromellitic dianhydride or biphenyltetracarboxylic dianhydride; and a crosslinkable monomer or crosslinkable capping agent selected from at least one of 4-ethynylphthalic anhydride, 4-methyl-ethynylphthalic anhydride, 4-phenylethynylphthalic anhydride (PEPA) or 4,4'-(ethyne-1,2-dicarbonyl)dianhydride.

[0331] Aspect 159. A method for manufacturing a reactive ammonium carboxylate, the method comprising: heating at least one aromatic diamine, at least one aromatic di-, tri- or tetra-carboxylic acid or a functional equivalent thereof, and at least one crosslinkable monomer or crosslinkable capping agent in the presence of C 1-4 alcohol at a temperature and for a time sufficient to form the reactive ammonium carboxylate; removing the excess C 1-4 alcohol; wherein the crosslinkable monomer or crosslinkable capping agent is reactive with the at least one aromatic diamine or the at least one di-, tri- or tetra-functional aromatic carboxylic acid or a functional equivalent thereof and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive ammonium carboxylate.

[0332] Aspect 160. A method of compounding a reactive ammonium carboxylate according to any one of Aspects 141 to 158, comprising mixing the reactive ammonium carboxylate with at least one other material at a temperature, pressure and time sufficient to prepare but not crosslink a reactive polyamideimide oligomer.

[0333] Aspect 161. A method for manufacturing an article, the method comprising heating a reactive ammonium carboxylate according to any one of Aspects 141 to 158 at a temperature, pressure and time sufficient to prepare, shape and crosslink a reactive polyamideimide oligomer.

[0334] Aspect 162. The manufacturing method according to Aspect 161, wherein the sufficient temperature, pressure and time are about 300 °C to about 400 °C, 0 to about 300 MPa and about 10 to about 60 minutes.

[0335] Aspect 163. The manufacturing method according to Aspect 161 or 162, wherein the method is fiber reinforced composite manufacturing, pultrusion, compression molding, injection molding or solution casting.

[0336] Aspect 164. An article manufactured by the method according to any one of Aspects 161 to 163.

[0337] Aspect 165. The manufacturing method according to any one of Aspects 161 to 163, wherein the method is for manufacturing fiber-reinforced composite materials.

[0338] Aspect 166. The method according to Aspect 165, the method comprising heating at least one layer of fiber fabric and at least one layer of reactive ammonium carboxylate salt in the form of powder or film at a temperature, pressure and time sufficient to impregnate the fiber fabric with the reactive ammonium carboxylate salt and to prepare and crosslink the reactive polyamide-imide oligomer to form a fiber-reinforced composite material.

[0339] Aspect 167. The method according to Aspect 165, the method comprising: impregnating at least one layer of fiber fabric with a solution of reactive ammonium carboxylate salt dissolved in a polar solvent; removing the polar solvent under reduced pressure; and heating at a temperature, pressure and time sufficient to polymerize and crosslink the reactive polyamide-imide oligomer to form a fiber-reinforced composite material.

[0340] Aspect 168. A fiber-reinforced composite material manufactured by the method according to any one of Aspects 165 to 167.

[0341] Aspect 169. The fiber-reinforced composite material according to Aspect 168, wherein the composite material is a multi-layer carbon-reinforced composite material.

[0342] Aspect 170. The manufacturing method according to any one of Aspects 161 to 163, wherein the method is solution casting and comprises: casting a solution of reactive ammonium carboxylate salt dissolved in a polar solvent onto a mold; removing the polar solvent to form a reactive ammonium carboxylate salt film; and heating the reactive ammonium carboxylate salt film at a temperature, pressure and time sufficient to prepare and crosslink the reactive polyamide-imide oligomer to form a flexible film.

[0343] Aspect 171. A flexible film manufactured by the solution casting method according to Aspect 170.

[0344] Aspect 172. The manufacturing method according to any one of Aspects 161 to 163, wherein the method is injection molding.

[0345] Aspect 173. The manufacturing method according to any one of Aspects 161 to 163, wherein the method is blow molding.

[0346] Examples

[0347] Materials and methods

[0348] The abbreviations of the materials used or mentioned herein are defined in Table 2. For those materials used in the examples, the sources are provided. Keywords for other abbreviations used herein are provided in Table 3.

[0349] Table 2. Materials

[0350]

[0351]

[0352] Table 3. Other Abbreviations

[0353]

[0354]

[0355] Rheology. At N 2 The melt complex viscosity is measured by oscillatory shear rheology at a heating rate of 10 °C / min, a frequency of 2 radians / sec, and a strain of 0.03% to 1.0%. A sample with a diameter of 13 mm is centered between parallel plates with a diameter of 25 mm for measurement.

[0356] Thermogravimetric analysis (TGA). For the determination of T d，5％重量损失 : TA Instruments TGA 5500, Pt pan, 10 °C / min, N 2 , 10 mg sample.

[0357] Differential scanning calorimetry (DSC). For the determination of T g : TA Instruments DSC2500, Tzero pan with a sealed lid, 10 °C / min, N 2 , approximately 7 mg sample. In this method, T g is determined by the inflection point.

[0358] Dynamic mechanical thermal analysis (DMTA). TA Instruments RSA G2 in tension mode, from 25 °C to 400 °C at 2 °C / min, N 2 atmosphere, sample size = 0.030 mm × 2 mm × 10 mm. In this method, T g is determined by the maximum of the peak of the loss modulus.

[0359] Stress-strain measurement. TA Instruments RSAG2 (32 N load cell), strain rate of 1 mm / min, sample size = approximately 0.030 mm × approximately 2 mm × 10 mm. The Young's modulus is determined by a linear fit of the stress-strain curve in the elastic region; between 0.1 and 0.3% strain.

[0360] Gel permeation chromatography (GPC). The Shimadzu Prominence ultra-fast liquid chromatography (UFLC) system is equipped with an LC20AD pump, a SIL-20AHT autosampler, a CTO-20A column oven at 60 °C, and an RID-20A refractive index detector. For the measurement, the chromatographic column used is SHODEX TMLF-804. The eluent for measurement is NMP containing 0.05 M LiBr and 0.05 M H 3 PO 4 and is run at a constant flow rate of 0.5 mL / min. The relative molecular weight is obtained by comparison with a SHODEX TM polystyrene standard.

[0361] Example 1

[0362] The manufacture of the reactive polyamideimide oligomer is illustrated in Scheme 5 below. The molecular weight of the oligomer affects the thermal, (thermo)mechanical, and melt properties of the reactive polyamideimide oligomer. In this example, a phenylacetylene end-capping agent (PEPA) is used to prepare reactive polyamideimide oligomers with M n values of 5000 g / mol (Examples 1B - 1E), 3000 g / mol (Examples 1F - 1G), and 8000 g / mol (Examples 1H - 1I). The Carothers equation (Eq. 2) is used to calculate the amount of monomers required to prepare a reactive polyamideimide oligomer with the desired M n value. Keeping M n constant, when more than one diamine monomer is used, the relative molar amounts of the diamine monomers will affect the rigidity of the oligomeric backbone. Thus, the thermal, (thermo)mechanical, and melt properties of the reactive polyamideimide oligomer can be changed by varying the ratio of the diamine monomers. In Example 1A, the M n of the reactive polyamideimide oligomer is 5000 g / mol and the backbone is composed of two diamines, 4,4'-ODA and 1,3-PD, in a molar ratio of 0.72:0.28. Changing the molar ratio of the two diamines will result in changes in the oligomer properties. The molar ratio of 4,4'-ODA to 1,3-PD is 0.72:0.28 in Examples 1A - 1I, 0.62:0.32 in Examples 1J - 1K, and 0.813:0.197 in Examples 1L - 1M.

[0363]

[0364] Scheme 5. Synthesis of reactive polyamideimide oligomers with phenylacetylene reactive end groups.

[0365] Example 1A - Reactive polyamide acid oligomer solution, M n = 5000 g / mol

[0366] In a 150 mL two-neck round-bottom flask equipped with a stir bar and a nitrogen inlet tube, 1,3-phenylenediamine (6.38 mmol, 0.69 g), 4,4'-oxydianiline (16.33 mmol, 3.27 g), and 37 g of NMP were charged. The mixture was stirred until a homogeneous solution was obtained. The solution was cooled to 0 °C. Trimellitic anhydride chloride (21.28 mmol, 4.48 g) and 4-(phenylethynyl)phthalic anhydride (2.9 mmol, 0.72 g) were added all at once. This reaction mixture was stirred at 0 °C under a nitrogen atmosphere for 1 to 2 hours, then the ice bath was removed, and the reaction mixture was stirred and warmed to 25 °C overnight (about 16 h), providing a solution of the reactive polyamide amic acid oligomer in NMP.

[0367] Example 1B - Reactive polyamideimide oligomer film, M n = 5000 g / mol

[0368] This is an example of preparing a free-standing reactive polyamideimide oligomer film without curing the phenylethynyl end groups. The solution of the reactive polyamide amic acid oligomer (10 mL) prepared in Example 1A was cast onto a glass plate and dried in vacuo at 60 °C. The temperature was gradually raised to 100 °C for 1 h, 200 °C for 1 h, and 300 °C for 1 h to dehydrate the reactive polyamide amic acid oligomer, obtaining a reactive polyamideimide oligomer with unreacted phenylethynyl end groups. The film was brittle and difficult to handle, which is a direct consequence of the low molecular weight. T g was 248 °C, measured by differential scanning calorimetry (N 2 , 10 °C / min).

[0369] Example 1C - cured polyamideimide oligomer film, M n = 5000 g / mol

[0370] This is an example of preparing a flexible, free-standing film with cured phenylethynyl end groups. The solution of the reactive polyamide amic acid oligomer (10 mL) prepared as in Example 1A was cast onto a glass plate and dried in vacuo at 60 °C. The temperature was gradually raised to 100 °C for 1 h, 200 °C for 1 h, and 300 °C for 1 h to dehydrate the reactive polyamide amic acid oligomer, obtaining a reactive polyamideimide oligomer with unreacted phenylethynyl end groups. The temperature was raised to 370 °C and the film was held at this temperature for 1 hour. After the film was cooled to 25 °C, a flexible and tough film was obtained. Thermogravimetric analysis (N 2 , 10 °C / min) showed a 5% weight loss at 483 °C. Differential scanning calorimetry (N 2 , 10 °C / min) showed T g to be 301 °C. Dynamic mechanical thermal analysis (N 2 , 10 °C / min, 1 Hz) showed that the storage modulus (E') at 33 °C was 3.2 GPa and at 300 °C was 0.81 GPa, Tg It was 306.8 °C. The stress-strain experiment (25 °C) showed that the Young's modulus of the film was 3.4 GPa, the fracture strength was 134 MPa, and the fracture strain was 17%. The film properties exceeded the expectations for high molecular weight polymer films.

[0371] Example 1D - Separated reactive polyamideimide oligomer powder, M n = 5000 g / mol

[0372] The imidized reactive polyamideimide oligomer powder was obtained by precipitating the solution of the reactive polyamideamic acid of Example 1A in NMP in MeOH. The polyamideamic acid was precipitated by pouring 50 mL of the polyamideamic acid solution of Example 1A into 200 mL of MeOH in a Warring blender and mixing for 1 - 3 min. The precipitate was collected by filtration on a Buchner funnel and washed with an additional 200 mL of MeOH. The washed polyamideamic acid powder was dried in vacuo at 60 °C in an oven for 2 h. The reactive polyamideamic acid oligomer was dehydrated by gradually raising the temperature to 100 °C for 1 h, 200 °C for 1 h, and 260 °C for 1 h to obtain a reactive polyamideimide oligomer powder with unreacted phenylacetylene end groups. The parallel plate rheology (N 2 , 10 °C / min) of the fully imidized reactive polyamideimide oligomer showed a melt complex viscosity of 19000 Pa·s at 361 °C.

[0373] Example 1E - cured polyamideimide oligomer film, M n = 5000 g / mol

[0374] This is another example of preparing a flexible, free-standing film in the case of curing phenylacetylene end groups. The solution of the reactive polyamideamic acid oligomer of Example 1A was imidized as follows. Anhydrous toluene was added to the reaction flask. The water formed during the cyclodehydration (amide acid to imide) process was removed by azeotropic distillation. After 2 h, the reactive polyamideamic acid oligomer was 98% imidized, and the remaining toluene was removed by distillation. The solution (10 mL) of the resulting reactive polyamideimide oligomer in NMP (30 wt.% solids) was poured onto a glass plate and dried in vacuo at 60 °C. After cooling to room temperature, the temperature was gradually raised to 40 °C for 2 h, 60 °C for 2 h, 100 °C, 200 °C, 300 °C for 30 min, and 370 °C for 1 h. After the film was cooled to 25 °C, a flexible and tough film was obtained. Differential scanning calorimetry (N 2 , 10 °C / min) showed that T g was 326 °C, which was about 46 °C higher than the Tg (280 °C) of currently available PAI films.

[0375] Example 1F, cured polyamideimide oligomer film, M n = 3000 g / mol

[0376] Preparation of reactive polyamideimide oligomer with 4-phenylethynylphthalic anhydride as capping agent n A reactive polyamideimide oligomer with M 2 = 3000 g / mol was prepared. A 150 mL two-neck round-bottom flask equipped with a stir bar and a nitrogen inlet tube was charged with 1,3-phenylenediamine (22.84 mmol, 2.47 g), 4,4'-oxydianiline (62.07 mmol, 12.43 g) and 82 g of NMP. The mixture was stirred until a homogeneous solution was obtained. The solution was cooled to 0 °C. Trimellitic anhydride chloride (76.08 mmol, 16.02 g) and 4-(phenylethynyl)phthalic anhydride (17.64 mmol, 4.38 g) were added all at once. This reaction mixture was stirred at 0 °C for 1 to 2 hours under a nitrogen atmosphere, then the ice bath was removed and the reaction mixture was stirred and warmed to 25 °C overnight (about 16 h), providing a solution of the reactive polyamide amic acid oligomer in NMP. The solution of the reactive polyamide amic acid oligomer (10 mL) was poured onto a glass plate and dried in vacuo at 60 °C. The temperature was gradually raised to 100 °C for 1 h, 200 °C for 1 h and 300 °C for 1 h to dehydrate the reactive polyamide amic acid oligomer, obtaining a reactive polyamideimide oligomer with unreacted phenylethynyl end groups. The temperature was raised to 370 °C and the film was held at this temperature for 1 hour. After the film was cooled to 25 °C, a flexible film was obtained. Thermogravimetric analysis (N 2 , 10 °C / min) showed a 5% weight loss at 500 °C. Differential scanning calorimetry (N 2 , 10 °C / min) showed a Tg of 291 °C. Dynamic mechanical thermal analysis (N g , 10 °C / min, 1 Hz) showed that the storage modulus (E') was 1.71 GPa at 35 °C and 0.25 GPa at 300 °C, and T

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378]

[0377] Example 1G - Separated reactive polyamideimide oligomer powder, M n = 3000 g / mol

[0378] The imidized reactive polyamideimide oligomer powder was obtained by precipitating the solution of the reactive polyamideamic acid of Example 1D in MeOH. The polyamideamic acid was precipitated by pouring 50 mL of the polyamideamic acid solution of Example 1D into 200 mL of MeOH in a Warring blender and mixing for 1 - 3 min. The precipitate was collected by filtration on a Buchner funnel and washed with an additional 200 mL of MeOH. The washed polyamideamic acid powder was dried in an oven at 60 °C under vacuum for 2 h. The reactive polyamideamic acid oligomer was dehydrated by gradually raising the temperature to 100 °C for 1 h, 200 °C for 1 h, and 260 °C for 1 h to obtain a reactive polyamideimide oligomer powder with unreacted phenylethynyl end groups. The parallel plate rheology (N 2 , 10 °C / min) of the fully imidized reactive polyamideimide oligomer showed a melt complex viscosity of 5450 Pa·s at 361 °C.

[0379] Example 1 H–Cured polyamideimide oligomer film, M n = 8000 g / mol

[0380] A reactive polyamideimide oligomer with 4-phenylethynylphthalic anhydride reactive end groups, M n = 8000 g / mol, was prepared. A 150 mL two-neck round-bottom flask equipped with a stir bar and a nitrogen inlet tube was charged with 1,3-phenylenediamine (22.84 mmol, 2.47 g), 4,4'-oxydianiline (56.43 mmol, 11.30 g), and 73 g of NMP. The mixture was stirred until a homogeneous solution was obtained. The solution was cooled to 0 °C. Trimellitic anhydride chloride (76.08 mmol, 16.02 g) and 4-(phenylethynyl)phthalic anhydride (6.04 mmol, 1.5 g) were added all at once. This reaction mixture was stirred at 0 °C under a nitrogen atmosphere for 1 to 2 h, then the ice bath was removed, and the reaction mixture was stirred and warmed to 25 °C overnight (about 16 h) to provide a solution of the reactive polyamideamic acid oligomer in NMP. The solution of the reactive polyamideamic acid oligomer (10 mL) was poured onto a glass plate and dried under vacuum at 40 °C for 2 h and at 60 °C for 2 h. The reactive polyamideamic acid oligomer was dehydrated by gradually raising the temperature to 100 °C for 1 h, 200 °C for 1 h, and 300 °C for 1 h to obtain a reactive polyamideimide oligomer with unreacted phenylethynyl end groups. The temperature was raised to 370 °C and the film was held at this temperature for 1 h. After cooling to 25 °C, a flexible film was obtained. Thermogravimetric analysis (N 2 , 10 °C / min) showed a 5% weight loss at 490 °C. Differential scanning calorimetry (N 2 , 10 °C / min) showed a T g of 287 °C. Dynamic mechanical thermal analysis (N 2, 10 °C / min, 1 Hz) shows that the storage modulus (E') is 3.0 GPa at 35 °C and 0.75 GPa at 300 °C, and T g is 300 °C. The stress-strain experiment (25 °C) shows that the Young's modulus of the film is 3.1 GPa, the fracture strength is 139 MPa, and the fracture strain is 57.4%.

[0381] Example 1I – Separated reactive polyamideimide oligomer powder, M n = 8000 g / mol

[0382] The imidized reactive polyamideimide oligomer powder was obtained by precipitating the reactive polyamide amic acid solution of Example 1F in NMP in MeOH. The polyamide amic acid was precipitated by pouring 50 mL of the polyamide amic acid solution into 200 mL of MeOH in a Warring blender and mixing for 1 - 3 min. The precipitate was collected by filtration on a Buchner funnel and washed with an additional 200 mL of MeOH. The washed polyamide amic acid powder was dried in vacuo at 60 °C for 2 h in a tam oven. The reactive polyamide amic acid oligomer was dehydrated by gradually raising the temperature to 100 °C for 1 h, 200 °C for 1 h, and 260 °C for 1 h to obtain a reactive polyamideimide oligomer powder with unreacted phenylacetylene end groups. The parallel plate rheology (N 2 , 10 °C / min) shows a melt complex viscosity of 49902 Pa·s at 333 °C.

[0383] Example 1J - Cured oligomeric polyamideimide oligomer film, 4,4'-ODA:1,3-PD ratio = 0.62: 0.32, M n = 5000 g / mol

[0384] In this example, the molar ratio of the two diamines, 4,4'-ODA and 1,3-PD, was 0.62:0.32. A 150 mL two-neck round-bottom flask equipped with a stir bar and a nitrogen inlet tube was charged with 1,3-phenylenediamine (37.54 mmol, 4.06 g), 4,4'-oxydianiline (62.52 mmol, 12.52 g), and 92 g of NMP. The mixture was stirred until a homogeneous solution was obtained. The solution was cooled to 0 °C. Trimellitic anhydride chloride (93.89 mmol, 19.77 g) and 4-(phenylethynyl)phthalic anhydride (12.41 mmol, 3.08 g) were added all at once. This reaction mixture was stirred at 0 °C under a nitrogen atmosphere for 1 to 2 hours, then the ice bath was removed and the reaction mixture was stirred and allowed to warm to 25 °C overnight (about 16 hours) to afford a solution of the reactive polyamide acid oligomer in NMP. The solution of the reactive polyamide acid oligomer (10 mL) was cast onto a glass plate and dried under vacuum at 40 °C for 2 hours and at 60 °C for 2 hours. The temperature was gradually increased to 100 °C for 1 h, 200 °C for 1 h, and 300 °C for 1 h to dehydrate the reactive polyamide acid oligomer, obtaining a reactive polyamideimide oligomer with unreacted phenylethynyl end groups. The temperature was raised to 370 °C and the film was held at this temperature for 1 hour. After cooling to 25 °C, a flexible film was obtained. Thermogravimetric analysis (N 2 , 10 °C / min) showed a 5% weight loss at 478 °C. Differential scanning calorimetry (N 2 , 10 °C / min) showed T g to be 283 °C. Dynamic mechanical thermal analysis (N 2 , 10 °C / min, 1 Hz) showed that the storage modulus (E') was 2.0 GPa at 35 °C and 0.24 GPa at 300 °C, and T g was 291.3 °C. A stress-strain experiment (25 °C) showed that the Young's modulus of the film was 2.5 GPa, the fracture strength was 82.5 MPa, and the fracture strain was 10.1%.

[0385] Example 1K - Isolated reactive polyamideimide oligomer powder, 4,4'-ODA:1,3-PD ratio = 0.62:0.32, M n = 5000 g / mol

[0386] The imidized reactive polyamide-imide oligomer powder was obtained by precipitating the solution of the reactive polyamide amic acid oligomer of Example 1I in MeOH. The reactive polyamide amic acid oligomer was precipitated by pouring 50 mL of the reactive polyamide amic acid oligomer solution into 200 mL of MeOH in a Waring blender and mixing for 1 - 3 minutes. The precipitate was collected by filtration on a Büchner funnel and washed with an additional 200 mL of MeOH. The washed reactive polyamide amic acid oligomer powder was dried in an oven at 60 °C under vacuum for 2 hours. The reactive polyamide amic acid oligomer was dehydrated by gradually increasing the temperature to 100 °C for 1 h, 200 °C for 1 h, and 260 °C for 1 h to obtain a reactive polyamide-imide oligomer powder with unreacted phenylacetylene end groups. The parallel plate rheology (N 2 , 10 °C / min) of the fully imidized reactive polyamide-imide oligomer showed a melt complex viscosity of 40339 Pa·s at 370 °C.

[0387] Example 1L - Cured oligomeric polyamideimide oligomer film, 4,4'-ODA:1,3-PD ratio = 0.813: 0.197, M n = 5000 g / mol

[0388] In this example, the molar ratio of the two diamines; 4,4'-ODA and 1,3-PD was 0.813:0.187. A 150 mL two-neck round bottom flask equipped with a stir bar and a nitrogen inlet tube was charged with 1,3-phenylenediamine (18.77 mmol, 2.03 g), 4,4'-oxydianiline (81.70 mmol, 16.36 g), and 96 g of NMP. The mixture was stirred until a homogeneous solution was obtained. The solution was cooled to 0 °C. Trimellitic anhydride chloride (93.89 mmol, 19.77 g) and 4-(phenylacetylene)phthalic anhydride (12.41 mmol, 3.08 g) were added all at once. This reaction mixture was stirred at 0 °C under a nitrogen atmosphere for 1 to 2 hours, then the ice bath was removed, and the reaction mixture was stirred and warmed to 25 °C overnight (about 16 h) to provide a solution of the reactive polyamide amic acid oligomer in NMP. The solution of the reactive polyamide amic acid oligomer (10 mL) was poured onto a glass plate and dried under vacuum at 40 °C for 2 hours and at 60 °C for 2 hours. The reactive polyamide amic acid oligomer was dehydrated by gradually increasing the temperature to 100 °C for 1 h, 200 °C for 1 h, and 300 °C for 1 h to obtain a reactive polyamide-imide oligomer with unreacted phenylacetylene end groups. The temperature was raised to 370 °C and the film was held at this temperature for 1 hour. After cooling to 25 °C, a flexible film was obtained. Thermogravimetric analysis (N 2 , 10 °C / min) showed a 5% weight loss at 496 °C. Differential scanning calorimetry (N 2 , 10 °C / min) showed T gis 308 °C. Dynamic mechanical thermal analysis (N 2 , 10 °C / min, 1 Hz) shows that the storage modulus (E') is 2.5 GPa at 35 °C and 1.0 GPa at 300 °C, and the T g is 322 °C. Stress-strain experiments (25 °C) show that the Young's modulus of the film is 3.7 GPa, the fracture strength is 132 MPa, and the fracture strain is 12.6%.

[0389] Example 1M - Isolated reactive polyamideimide oligomer powder, 4,4'-ODA:1,3-PD ratio = 0.813:0.197, M n = 5000 g / mol

[0390] The imidized reactive polyamideimide oligomer powder was obtained by precipitating a solution of reactive polyamideamic acid oligomer in NMP in MeOH. The reactive polyamideamic acid oligomer was precipitated by pouring 50 mL of the reactive polyamideamic acid oligomer solution into 200 mL of MeOH in a Warring blender and mixing for 1 - 3 min. The mixture was washed in the Warring blender for 1 - 3 min. The precipitate was collected by filtration on a Buchner funnel and washed with an additional 200 mL of MeOH. The washed reactive polyamideamic acid oligomer powder was dried in an oven at 60 °C under vacuum for 2 h. The temperature was gradually increased to 100 °C for 1 h, 200 °C for 1 h, and 260 °C for 1 h to dehydrate the reactive polyamideamic acid oligomer, obtaining a reactive polyamideimide oligomer powder with unreacted phenylethynyl end groups. Parallel plate rheology (N 2 , 10 °C / min) of the fully imidized reactive polyamideimide shows a melt complex viscosity of 49502 Pa·s at 359 °C.

[0391] Example 2

[0392] Reactive polyamideimide (PAI) oligomers with M n = 5000 g / mol were made using two different end-capping agents as shown in Scheme 6 below. The two different end-capping agents are 4-(phenylethynyl)phthalic anhydride and 4-(methylethynyl)phthalic anhydride.

[0393]

[0394] Scheme 6. Synthesis of M n = 5000 g / mol fully aromatic reactive polyamideimide oligomers. 50 / 50 4-(phenylethynyl)phthalic anhydride / 4-(methylethynyl)phthalic anhydride.

[0395] Into a 150 mL two-necked round-bottom flask equipped with a stir bar and a nitrogen inlet tube, 1,3-phenylenediamine (6.38 mmol, 0.69 g), 4,4'-oxydianiline (16.33 mmol, 3.27 g) and 36 g of NMP were charged. The mixture was stirred until a homogeneous solution was obtained. The solution was cooled to 0 °C. Trimellitic anhydride chloride (21.28 mmol, 4.48 g), 4-(phenylethynyl)phthalic anhydride (1.45 mmol, 0.36 g) and 4-(methylethynyl)phthalic anhydride (1.45 mmol, 0.27 g) were added all at once. This reaction mixture was stirred at 0 °C under a nitrogen atmosphere for 1 to 2 hours, then the ice bath was removed and the reaction mixture was stirred and warmed to 25 °C overnight (about 16 hours). The prepared reactive polyamide acid oligomer solution (10 mL) was poured onto a glass plate and dried under vacuum at 60 °C. The temperature was gradually raised to 100 °C for 1 h, 200 °C for 1 h and 300 °C for 1 h to dehydrate the reactive polyamide acid oligomer, obtaining a reactive polyamideimide oligomer with unreacted phenylethynyl end groups. The temperature was raised to 370 °C and the film was maintained at this temperature for 1 hour. After the film was cooled to 25 °C, a flexible and tough film was obtained.

[0396] Thermogravimetric analysis (N 2 , 10 °C / min) showed a 5% weight loss at 466 °C. Differential scanning calorimetry (N 2 , 10 °C / min) showed T g to be 298 °C. Dynamic mechanical thermal analysis (N 2 , 10 °C / min, 1 Hz) showed that the storage modulus (E') was 2.6 GPa at 33 °C and 0.64 GPa at 300 °C, and T g was 301 °C. Parallel plate rheology (N 2 , 10 °C / min) showed a viscosity of 98560 Pa·s at 301 °C. The stress-strain experiment at 25 °C showed that the Young's modulus of the film was 3.6 GPa, the fracture strength was 155 MPa, the fracture elongation was 75%, and the toughness was 94.3 MJ / m 3 . In contrast, a review of the existing literature showed that currently available PAI only had a toughness of about 10 MJ / m 3 , a fracture strength of 140 MPa and a fracture elongation of 10 to 15%. Therefore, the toughness of the PAI film made from the reactive polyamideimide oligomer could be almost 10 times higher than that of currently available PAI, the fracture elongation could be about 5 times higher, and the fracture strength could be about 10% higher. Generally, crosslinking of polymers results in a decrease in fracture elongation. Surprisingly, when the reactive polyamideimide oligomer was crosslinked, both the fracture strength and the fracture elongation increased, resulting in a significant increase in toughness.

[0397] Example 3

[0398] The preparation of another reactive polyamideimide oligomer is shown in Scheme 7 below. TMACl is expensive, so it is desirable to minimize its use in the preparation of reactive polyamideimide oligomers. TMACl has an acyl chloride group and a carboxylic anhydride group. Instead of using one equivalent of TMACl, 1 / 2 equivalent of pyromellitic dianhydride (PMDA) and 1 / 2 equivalent of isophthaloyl chloride (IPC) were used.

[0399] Prepare M n with a reactive oligomer having a 4-(phenylethynyl)phthalic anhydride reactive end group and a weight average molecular weight of 5000 g / mol.

[0400]

[0401] Scheme 7. Synthesis of an M n = 5000 g / mol wholly aromatic reactive polyamideimide oligomer with 4-(phenylethynyl)phthalic anhydride reactive end groups. The trimellitic anhydride chloride of Example 2 was replaced with pyromellitic dianhydride and isophthaloyl chloride.

[0402] Charge pyromellitic dianhydride (10.64 mmol, 2.32 g), isophthaloyl chloride (10.64 mmol, 2.16 g), 4-(phenylethynyl)phthalic anhydride (2.9 mmol, 0.72 g) and 37 g of NMP into a 150 mL two-necked round bottom flask equipped with a stir bar and a nitrogen inlet tube. Stir this suspension for 15 min and cool to 0 °C. Add all at once the diamines, 1,3-phenylenediamine (6.38 mmol, 0.69 g) and 4,4'-oxydianiline (16.33 mmol, 3.27 g). Stir this reaction mixture at 0 °C under a nitrogen atmosphere for 1 h, then remove the ice bath and stir and warm the reaction mixture to 25 °C overnight (about 16 h). Pour the prepared reactive polyamideamic acid oligomer solution (10 mL) onto a glass plate and dry it under vacuum at 60 °C. Gradually raise the temperature to 100 °C for 1 h, 200 °C for 1 h and 300 °C for 1 h to dehydrate the reactive polyamideamic acid oligomer to obtain a reactive polyamideimide oligomer with unreacted phenylethynyl end groups. Raise the temperature to 370 °C and hold the film at this temperature for 1 h. After cooling the film to 25 °C, a flexible and tough film was obtained. Thermogravimetric analysis (N 2 , 10 °C / min) showed a 5% weight loss at 476 °C. Differential scanning calorimetry (N 2 , 10 °C / min) showed T gis 315 °C. Dynamic mechanical thermal analysis (N 2 , 10 °C / min, 1 Hz) shows that the storage modulus (E') is 2.8 GPa at 33 °C and 0.93 GPa at 300 °C, and the T g is 299 °C. Stress-strain experiments at 25 °C show that the Young's modulus of the film is 3.2 GPa, the fracture strength is 121 MPa, and the elongation at break is 25%.

[0403] Example 4

[0404] The preparation of another reactive polyamideimide oligomer is shown in Scheme 8 below. A crosslinkable dianhydride monomer (4,4'-(ethyne-1,2-diyl)diphthalic anhydride or EBPA) is incorporated into the reactive oligomer backbone. To limit the molecular weight (M n ) to 5000 g / mol, a phthalic anhydride (non-reactive) end-capping agent is used.

[0405]

[0406] Scheme 8. Synthesis of M n = 5000 g / mol of a wholly aromatic reactive polyamideimide oligomer having a crosslinkable acetylene-based dianhydride monomer (4,4'-(ethyne-1,2-diyl)diphthalic anhydride or EBPA) in the backbone. By using a non-reactive phthalic anhydride end-capping agent, the molecular weight (M n ) is limited to 5000 g / mol.

[0407] In a 150 mL two-neck round-bottom flask equipped with a stir bar and a nitrogen inlet tube, 4,4'-oxydiphthalic anhydride (ODPA) (7.98 mmol, 2.48 g), isophthaloyl chloride (10.64 mmol, 2.16 g), EBPA (2.66 mmol, 0.85 g), phthalic anhydride (2.9 mmol, 0.43 g) and 42 g of NMP were charged. This suspension was stirred for 15 min and cooled to 0 °C. The diamine 4,4'-oxydianiline (22.71 mmol, 4.55 g) was added all at once. This reaction mixture was stirred at 0 °C under a nitrogen atmosphere for 1 h, then the ice bath was removed, and the reaction mixture was stirred and warmed to 25 °C overnight (about 16 h). The prepared reactive polyamide acid oligomer solution (10 mL) was poured onto a glass plate and dried under vacuum at 60 °C to form a film. The temperature was gradually raised to 100 °C for 1 h, 200 °C for 1 h and 300 °C for 1 h to dehydrate the reactive polyamide acid oligomer, obtaining a reactive polyamideimide oligomer with unreacted phenylacetylene end groups. The temperature was raised to 370 °C and the film was held at this temperature for 1 h. After the film was cooled to 25 °C, a flexible and tough film was obtained. After cooling to 25 °C, a flexible and tough film was obtained. Thermogravimetric analysis (N 2 , 10 °C / min) showed a 5% weight loss at 463 °C. Differential scanning calorimetry (N 2 , 10 °C / min) showed that T g was 268 °C.

[0408] Another film was formed in the same manner, except that the reactive polyamideimide oligomer film was cured at 400 °C for 1 h instead of at 400 °C. Thermogravimetric analysis (N 2 , 10 °C / min) showed a 5% weight loss at 459 °C. Dynamic mechanical thermal analysis (N 2 , 10 °C / min, 1 Hz) showed that the storage modulus (E') was 2.0 GPa at 33 °C, 0.16 GPa at 300 °C, and T g was 282 °C. Stress-strain experiments at 25 °C showed that the Young's modulus of the film was 2.1 GPa, the fracture strength was 56 MPa, and the elongation at break was 3%.

[0409] Example 5

[0410] The preparation of another reactive polyamideimide oligomer is shown in Scheme 9 below. The crosslinkable dianhydride monomer (4,4'-(ethyne-1,2-diyl)diphthalic dianhydride or EBPA) was incorporated into the reactive oligomer backbone. To limit the molecular weight (M n ) to 5000 g / mol, the reactive end-capping agent 4-(phenylethynyl)phthalic anhydride was used.

[0411]

[0412] Scheme 9. Synthesis of M n = 5000 g / mol of a wholly aromatic reactive polyamideimide oligomer having a crosslinkable acetylene-based dianhydride monomer (4,4'-(ethyne-1,2-diyl)diphthalic anhydride or EBPA) in the backbone. The molecular weight (M n ) was limited to 5000 g / mol using the reactive 4-(phenylethynyl)phthalic anhydride end-capping agent.

[0413] Charge 4,4'-oxydiphthalic anhydride (ODPA) (7.98 mmol, 2.48 g), isophthaloyl chloride (10.64 mmol, 2.16 g), EBPA (2.66 mmol, 0.85 g), 4-(phenylethynyl)phthalic anhydride (2.9 mmol, 0.72 g) and 42 g of NMP into a 150 mL two-necked round-bottom flask equipped with a stir bar and a nitrogen inlet tube. Stir this suspension for 15 minutes and cool to 0 °C. Add all at once the diamine 4,4'-oxydianiline (22.71 mmol, 4.55 g). Stir this reaction mixture at 0 °C under a nitrogen atmosphere for 1 hour, then remove the ice bath, stir the reaction mixture and warm to 25 °C overnight (about 16 hours).

[0414] Example 5A

[0415] This is an example of preparing a free-standing polyamideimide film obtained by selectively curing the phenylethynyl end groups rather than the backbone ethynyl groups. Pour the prepared reactive polyamideamic acid oligomer solution (10 mL) onto a glass plate and dry it under vacuum at 60 °C. Gradually raise the temperature to 100 °C for 1 h, 200 °C for 1 h, 300 °C for 1 h to dehydrate the reactive polyamideamic acid oligomer, obtaining a reactive polyamideimide oligomer having unreacted phenylethynyl end groups. Raise the temperature to 370 °C and hold the film at this temperature for 1 hour. After cooling the film to 25 °C, a flexible and tough film is obtained. Differential scanning calorimetry (N 2 , 10 °C / min) shows that T g is 298 °C. Dynamic mechanical thermal analysis (N 2 , 10 °C / min, 1 Hz) shows that the storage modulus (E') at 33 °C is 2.3 GPa and T g is 302 °C.

[0416] Example 5B

[0417] This is an example of preparing a free-standing polyamideimide film using a cured phenylacetylene end group and a backbone acetylene group. The prepared reactive polyamideamic acid oligomer solution (10 mL) was cast onto a glass plate and dried in vacuo at 60 °C. The temperature was gradually increased to 100 °C for 1 h, 200 °C for 1 h, and 300 °C for 1 h to dehydrate the reactive polyamideamic acid oligomer, obtaining a reactive polyamideimide oligomer with unreacted phenylacetylene end groups. The temperature was raised to 400 °C and the film was held at this temperature for 1 hour. At this temperature, both the phenylacetylene end groups and the backbone acetylene groups were cured. After the film was cooled to 25 °C, a flexible and tough film was obtained. Thermogravimetric analysis (N 2 , 10 °C / min) showed a 5% weight loss at 453 °C. Dynamic mechanical thermal analysis (N 2 , 10 °C / min, 1 Hz) showed a storage modulus (E') of 2.7 GPa at 33 °C, and T g was 324 °C. The stress-strain experiment at 25 °C showed that the Young's modulus of the film was 2.6 GPa, the fracture strength was 78 MPa, and the elongation at break was 4%.

[0418] Example 6

[0419] Another reactive polyamideimide oligomer with M n = 5000 g / mol was prepared using the ammonium carboxylate salt route as shown in Scheme 10 below.

[0420]

[0421] Scheme 10. Synthesis of M n = 5000 g / mol fully aromatic reactive polyamideimide oligomer.

[0422] Into a flame-dried 3-necked 500 mL round-bottom flask equipped with a reflux condenser and a nitrogen inlet adapter were charged 0.2556 mol (49.11 g) of trimellitic anhydride, 0.036 mol (8.94 g) of 4-(phenylacetylene)phthalic anhydride, and 85 g of MeOH. The mixture was refluxed under nitrogen at 70 °C for 2 h. To this mixture was added portionwise 0.2730 mol (54.67 g) of 4,4'-oxydianiline. The mixture was refluxed for 24 h, and methanol was removed by evaporation. The resulting ammonium carboxylate salt was dried in vacuo at 70 °C. The salt was heated to 300 °C under nitrogen at 10 °C / min and held isothermally at 300 °C for 1 h at 3 atm pressure to obtain a reactive polyamideimide oligomer.

[0423] Thermogravimetric analysis (N 2 , 10 °C / min) showed a 5% weight loss at 510 °C. Differential scanning calorimetry (N2 , 10 °C / min) shows the T of the oligomer before crosslinking g to be 226 °C. After thermal crosslinking of the reactive oligomer (1 hour at 370 °C), the T g increases from 226 °C to 287 °C. Fourier transform infrared spectroscopy (FTIR) using a PerkinElmer spectrometer, ATR mode: 1718 cm -1 (imide C=O), 1660 cm -1 (amide C=O) and 1374 cm -1 (imide C-N).

[0424] Example 7

[0425] Reactive polyamideimide (PAI) oligomers are prepared by melt oligomerization as illustrated in Scheme 11 below. Phenylacetylene end-capper (PEPA) is used to prepare M n reactive oligomers with M = 5000 g / mol.

[0426]

[0427] Scheme 11. Synthesis of M = 5000 g / mol fully aromatic reactive polyamideimide oligomers with phenylacetylene reactive end-groups by melt polymerization n reactive polyamideimide oligomers.

[0428] Charge 1,3-phenylenediamine (63.8 mmol, 6.9 g), 4,4'-oxydianiline (163.3 mmol, 32.7 g), trimellitic anhydride (212.8 mmol, 40.9 g), 4-(phenylacetylene)phthalic anhydride (29 mmol, 7.2 g) and 200 mL glacial acetic acid into a 500 mL 2-neck round-bottom flask equipped with an overhead stirrer and a nitrogen inlet tube. Heat the resulting reaction mixture under reflux for 2 hours, then add 20 mL acetic anhydride and reflux the reaction for another 1 hour. Remove acetic acid, residual acetic anhydride and water formed during the reaction by vacuum distillation. Feed the resulting yellow monomer mixture into an Xplore twin-screw extruder with venting capacity at 290 °C. The melt is circulated in the extruder at 290 °C and 50 rpm for 55 minutes for polymerization. Polymerization is monitored by measuring the relationship of the axial force (N) versus time (min), as Figure 3 shown. When the axial force reaches 5000 N (55 min), polymerization is judged to be complete. At this time, the reactive PAI oligomers are extruded as continuous amber filaments and analyzed.

[0429] To confirm that reactive oligomers rather than crosslinked materials are obtained, a small amount of the sample is dissolved in NMP. GPC analysis against a polystyrene standard shows M nIt was 4500, and the polydispersity index (PDI) was 2.22. TGA was run on the resulting filaments at a rate of 10 °C / min under nitrogen and showed a 1% mass loss at 395 °C and a 5% mass loss at 448 °C. The powder sample was compressed in a 13 mm press mold and subjected to oscillatory shear heating from 30 °C to 350 °C at a strain of 0.03% and 2 rad / s with a heating rate of 10 °C / min. The lowest viscosity recorded was 33000 Pa·s.

[0430] The filament sample was ground into a powder and dissolved at 20 wt% in NMP overnight, and then cast into a film with a thickness of approximately 40 μm. The film was cured under vacuum at 40 °C for 2 h, at 60 °C for 1.5 h, and at 100 °C, 200 °C, 300 °C, and 350 °C for 1 h each. The cured film was subjected to uniaxial deformation and showed an optimum fracture stress of 115 MPa at a strain of 17% and a modulus of 3 GPa. The sample was subjected to uniaxial oscillatory heating from 30 °C to 400 °C at a strain of 0.03% and 2 rad / s with a heating rate of 2 °C / min. The sample showed a modulus of 3 GPa and a T g 。

[0431] Example 8

[0432] This is an example of preparing a nanocomposite film containing reduced graphene oxide (rGO) 2-D nanoparticles. Graphene oxide (GO) in NMP (0.53 wt% colloid of 2.26 g) was added dropwise to a reactive polyamide acid oligomer solution of 3.6 g of 30 wt% 5000 g / mol (M n ) (the ratio of GO to resin = 1:10), and stirring was carried out. After stirring for 1 h, the reactive polyamide acid oligomer graphene oxide solution (4 mL) was cast on a glass plate and dried at 40 °C for 2 h and then dried under vacuum at 60 °C for 2 h. The temperature was gradually raised to 100 °C for 1 h, 200 °C for 1 h, and 300 °C for 1 h to obtain a reactive polyamideimide oligomer-reduced graphene oxide nanocomposite with unreacted phenylacetylene end groups. During the heating process, due to the elimination of oxygen groups, GO underwent partial thermal reduction to form rGO. The temperature was raised to 370 °C, and the nanocomposite film was held at this temperature for 1 h. After cooling to 25 °C, a flexible nanocomposite film was obtained.

[0433] Differential scanning calorimetry (N 2 , 10 °C / min) showed a T g of 296 °C. Dynamic mechanical thermal analysis (N 2 , 10 °C / min, 1 Hz) showed that the storage modulus (E') was 5.8 GPa at 35 °C and 2.5 GPa at 300 °C, and Tg is 314 °C. The stress-strain experiment (25 °C) shows that the Young's modulus of the film is 5.0 GPa, the fracture strength is 65 MPa, and the fracture strain is 1.32%.

[0434] The nanocomposite film containing reduced graphene oxide (rGO) 2-D nanoparticles can also be prepared using the ester of the reactive polyamide amic acid oligomer of Example 1A. In addition, an amine solvent (such as acrylamide) can be used instead of NMP to disperse GO. Such a GO dispersion can be mixed with a reactive polyamide amic acid oligomer solution (as in this example) or a reactive polyamide amic acid oligomer ester solution.

[0435] Example 9

[0436] This is an example of preparing a continuous carbon fiber 4-layer composite by the prepreg route. A four (4)-layer (20×20 cm) plain weave carbon fiber fabric T650 is impregnated with a 20 wt% solution of 5000 g / mol (M n ) reactive polyamide amic acid oligomer (fiber resin ratio = 60:40). After allowing NMP to evaporate (vacuum, 50 °C), the prepreg is heated in a vacuum oven to convert the reactive polyamide amic acid oligomer into a closed-loop reactive polyamide imide oligomer. The thermal profile used: 1 h at 100 °C, 1 h at 200 °C, 1 h at 300 °C. The 4 layers are stacked between KAPTON TM foil (50 μm) coated with a high-temperature release agent (MARBOCOTE 227) and placed between two steel plates of a parallel plate press, as Figure 1 shown.

[0437] The parallel plate press is heated to 300 °C and the stack (as Figure 1 shown) is placed in the press. The stack is consolidated with a pressure of 5 tons. Within 15 minutes, the temperature rises to 370 °C, and after 10 minutes at 370 °C, the pressure rises to 30 tons. The stack is held at 370 °C / 30 tons for 30 minutes, after which the heater is turned off and the stack is allowed to cool to 25 °C. A hard and firm panel is obtained, which shows an obvious metallic sound. No resin is discharged from the panel.

[0438] Example 10

[0439] This is an example of preparing a continuous carbon fiber 5-layer composite by resin powder melt infusion. Five (5)-layer (20×20 cm) plain carbon fiber fabric T650 is combined with 7 g of fully imidized 5000 g / mol (M n)Reactive polyamide amide oligomer powder (about 20 μm) is placed between each layer. Five layers are stacked on a KAPTONTM foil (50 μm) coated with a high-temperature release agent (MARBOCOTE 227) and placed between two steel plates of a parallel plate press. The parallel plate press is heated to 375 °C and the stack is placed in the press. The stack is consolidated with a pressure of 5 tons. Within 15 minutes, the pressure is increased from 5 tons to 25 tons, and the stack is maintained at this pressure and 375 °C for 45 minutes. Then the heater is turned off and the stack is allowed to cool to 25 °C. A well-consolidated panel is obtained and no resin is discharged from the panel.

[0440] The reactive oligomers described herein, namely reactive polyamideimide oligomers and reactive polyamide acid oligomers, may also be referred to as "macromonomers".

[0441] As used herein, a "crosslinkable monomer" refers to a monomer that is reactive with at least one aromatic diamine or at least one di-, tri- or tetra-functional aromatic carboxylic acid or a functional equivalent thereof and has unreacted functional groups capable of chain extension and crosslinking after the formation of a reactive polyamideimide oligomer.

[0442] As used herein, a "crosslinkable capping agent" refers to a capping agent that is reactive with at least one aromatic diamine or at least one di-, tri- or tetra-functional aromatic carboxylic acid or a functional equivalent thereof and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of a reactive polyamideimide oligomer.

[0443] As used herein, a "non-crosslinkable capping agent" refers to a capping agent that is reactive with at least one aromatic diamine or at least one di-, tri- or tetra-functional aromatic carboxylic acid or a functional equivalent thereof but does not have unreacted functional groups capable of chain extension and crosslinking after the formation of a reactive polyamideimide oligomer.

[0444] As used herein, curing generally refers to any combination of chain extension, branching and crosslinking that results in enhanced thermomechanical properties. Curing can be initiated by heat, actinic (electromagnetic) radiation or electron beam radiation. The terms "thermal curing", "thermal post-treatment" and "thermal post-curing" can be used interchangeably for curing initiated by heat.

[0445] The terms "acetylene" and "alkyne" are used interchangeably herein.

[0446] The terms "additive manufacturing" and "3D printing" are used interchangeably herein.

[0447] The terms "fused filament fabrication" and "fused deposition modeling" are used interchangeably herein.

[0448] As used herein in connection with a list, "at least one" means that the list includes each individual element of the list, as well as combinations of two or more elements of the list, and combinations of at least one element of the list with other similar unnamed elements.

[0449] The compositions, methods, and articles may alternatively comprise any suitable materials, steps, or components disclosed herein, consist of, or consist essentially of any suitable materials, steps, or components disclosed herein. The compositions and methods may additionally or alternatively be formulated so as to be free or substantially free of any materials (or species), steps, or components that are not necessary to achieve the functions or objectives of the compositions and methods.

[0450] All ranges disclosed herein include the endpoints, and the endpoints can be combined independently of each other (e.g., the range "less than or equal to 25 wt.%, or more specifically, 5 wt.% to 20 wt.%" includes the endpoints and all intermediate values of the range, including, for example, "5 wt.% to 25 wt.%"). The reference herein to "about" a value or parameter includes (and describes) embodiments directed to the value or parameter itself. In certain embodiments, the term "about" includes an indication of the amount ±50%. In certain other embodiments, the term "about" includes an indication of the amount ±20%. In certain other embodiments, the term "about" includes an indication of the amount ±10%. In other embodiments, the term "about" includes an indication of the amount ±5%. In certain other embodiments, the term "about" includes an indication of the amount ±1%. In certain other embodiments, the term "about" includes an indication of the amount ±0.5%, and in certain other embodiments, 0.1%. Such variations are suitable for carrying out the disclosed methods or employing the disclosed compositions. Additionally, the term "about x" includes the description of "x".

[0451] "Combination" includes blends, mixtures, alloys, reaction products, etc. Unless otherwise stated herein or clearly contradicted by the context, the terms "a", "an", and "the" do not denote a limitation of quantity and should be construed to cover both the singular and the plural. Unless otherwise expressly stated, "or" means "and / or".

[0452] References throughout the specification to "some embodiments", "one embodiment", etc. mean that a particular element described in connection with the embodiment is included in at least one embodiment described herein, and may or may not be present in other embodiments. Furthermore, it should be understood that the described elements may be combined in any suitable manner in various embodiments.

[0453] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. All cited patents, patent applications, and other references are incorporated herein by reference in their entirety. However, if a term in this application contradicts or conflicts with a term in the incorporated references, the term in this application shall prevail over the conflicting term in the incorporated references.

[0454] Although specific embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are presently unforeseen or may not be foreseeable to the applicant or other skilled artisans in the art may be contemplated. Accordingly, the appended aspects as submitted, and as they may be modified, are intended to cover all such alternatives, modifications, variations, improvements, and substantial equivalents.

[0455] The present invention relates to the following technical solutions:

[0456] 1. A reactive polyamideimide oligomer comprising units derived from at least one aromatic diamine, at least one aromatic di-, tri-, or tetra-functional carboxylic acid or a functional equivalent thereof, and at least one crosslinkable monomer or crosslinkable capping agent;

[0457] wherein the crosslinkable monomer or crosslinkable capping agent is reactive with the at least one aromatic diamine or at least one di-, tri-, or tetra-functional aromatic carboxylic acid or a functional equivalent thereof and has at least one unreacted functional group capable of undergoing thermal chain extension and crosslinking after the formation of the reactive polyamideimide oligomer; and

[0458] wherein the number average molecular weight (M n ) of the reactive polyamideimide oligomer is calculated using the Carothers equation to be from about 1000 to about 10000 g / mol.

[0459] 2. The reactive polyamideimide oligomer according to technical solution 1, wherein the reactive polyamideimide oligomer is derived from a reactive polyamideamic acid oligomer intermediate by dehydration cyclization, and more than 80% and less than or equal to 100% of the amic acid groups in the reactive polyamideamic acid intermediate are imidized.

[0460] 3. The reactive polyamideimide oligomer according to technical solution 1, wherein the reactive polyamideimide oligomer is derived from a reactive polyamideamic acid oligomer intermediate by dehydration cyclization, and more than or equal to 20% and less than or equal to 80% of the amic acid groups in the reactive polyamideamic acid intermediate are imidized.

[0461] 4. The reactive polyamideimide oligomer according to any one of Technical Solutions 1 to 3, wherein the crosslinkable monomer or crosslinkable capping agent has an unreacted functional group capable of thermal chain extension and crosslinking after the formation of the reactive polyamideimide oligomer.

[0462] 5. The reactive polyamideimide oligomer according to any one of Technical Solutions 1 to 4, wherein the at least one crosslinkable monomer or crosslinkable capping agent is at least one crosslinkable capping agent.

[0463] 6. The reactive polyamideimide oligomer according to any one of Technical Solutions 1 to 5, wherein the at least one aromatic diamine is two aromatic diamines.

[0464] 7. The reactive polyamideimide oligomer according to any one of Technical Solutions 1 to 6, wherein the at least one aromatic di-, tri- or tetra-functional carboxylic acid or its functional equivalent is two aromatic di-, tri- or tetra-functional carboxylic acids or their functional equivalents.

[0465] 8. The reactive polyamideimide oligomer according to any one of Technical Solutions 1 to 7, which is prepared by a method comprising: simultaneously stepwise polymerizing at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or its functional equivalent, and at least one crosslinkable monomer or crosslinkable capping agent.

[0466] 9. The reactive polyamideimide oligomer according to any one of Technical Solutions 1 to 8, wherein the aromatic diamine is at least one of the following:

[0467]

[0468] 10. The reactive polyamideimide oligomer according to any one of Technical Solutions 1 to 9, wherein the aromatic diamine is at least one of 1,3-phenylenediamine, 4,4'-oxydianiline, and 3,4'-oxydianiline.

[0469] 11. The reactive polyamideimide oligomer according to any one of Technical Solutions 1 to 10, wherein the di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent is at least one of the following:

[0470]

[0471] 12. The reactive polyamideimide oligomer according to any one of Technical Solutions 1 to 11, wherein the di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent is at least one of trimellitic anhydride, 4-chlorocarbonylphthalic anhydride, phthalic anhydride, isophthaloyl chloride, pyromellitic dianhydride, or biphenyltetracarboxylic dianhydride.

[0472] 13. The reactive polyamideimide oligomer according to any one of Technical Solutions 1 to 12, wherein the unreacted functional group is at least one of acetylene, methylacetylene, phenylacetylene, ketoacetylene, propargyl ether, norbornene, maleimide, cyanate ester, phthalonitrile, benzocyclobutene, biphenyl or benzoxazine.

[0473] 14. The reactive polyamideimide oligomer according to any one of Technical Solutions 1 to 13, wherein the crosslinkable monomer or crosslinkable capping agent is at least one of the following:

[0474]

[0475]

[0476] 15. The reactive polyamideimide oligomer according to any one of Technical Solutions 1 to 14, wherein the crosslinkable monomer or crosslinkable capping agent is at least one of 4-ethynylphthalic anhydride, 4-methyl-ethynylphthalic anhydride, 4-phenyl-ethynylphthalic anhydride (PEPA) or 4,4'-(ethyne-1,2-diyl) diphthalic anhydride.

[0477] 16. The reactive polyamideimide oligomer according to any one of Technical Solutions 1 to 15, which comprises two crosslinkable monomers or crosslinkable capping agents having reactivity in different temperature ranges.

[0478] 17. The reactive polyamideimide oligomer according to any one of Technical Solutions 1 to 16, which further comprises units derived from at least one non-crosslinkable capping agent, wherein the non-crosslinkable capping agent is reactive with the at least one aromatic diamine or at least one di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent.

[0479] 18. The reactive polyamideimide oligomer according to Technical Solution 17, wherein the non-crosslinkable capping agent is at least one of benzoic acid, benzoyl chloride, phthalic anhydride or aniline.

[0480] 19. The reactive polyamideimide oligomer according to any one of Technical Solutions 1 to 18, which further comprises units derived from at least one of aromatic triamine, aromatic tricarboxylic acid or aromatic tricarboxylic acid chloride.

[0481] 20. The reactive polyamideimide oligomer according to any one of Technical Solutions 1 to 19, wherein the melt complex viscosity of the reactive polyamideimide oligomer at 360 °C is about 1000 to about 100000 Pa·s, and the melt complex viscosity is at N 2It is measured by oscillatory shear rheology between parallel plates at a heating rate of 10 °C / minute, a frequency of 2 radians / second, and a strain of 0.03% to 1.0%.

[0482] 21. A reactive polyamideimide oligomer comprising units derived from:

[0483] At least one aromatic diamine selected from the following:

[0484]

[0485] At least one di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent selected from the following:

[0486] And at least one crosslinkable monomer or crosslinkable capping agent selected from the following:

[0487]

[0488]

[0489] 22. A reactive polyamideimide oligomer comprising units derived from:

[0490] At least one aromatic diamine selected from 1,3-phenylenediamine, 4,4'-oxydianiline or 3,4'-oxydianiline;

[0491] At least one di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent selected from trimellitic anhydride, 4-chlorocarbonyl phthalic anhydride, isophthalic anhydride, isophthaloyl chloride, pyromellitic dianhydride or biphenyltetracarboxylic dianhydride; and

[0492] At least one crosslinkable monomer or crosslinkable capping agent selected from 4-ethynylphthalic anhydride, 4-methylethynylphthalic anhydride, 4-phenylethynylphthalic anhydride (PEPA) or 4,4'-(ethyne-1,2-diyl)diphthalic anhydride.

[0493] 23. A method for manufacturing a reactive polyamideimide oligomer according to any one of Technical Solutions 1 to 22, the method comprising: copolymerizing at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or its functional equivalent, and at least one crosslinkable monomer or crosslinkable capping agent in the presence of a polar solvent to form a reactive polyamideamic acid oligomer; and

[0494] Heating the reactive polyamideamic acid oligomer at a temperature and for a time sufficient to prepare the reactive polyamideimide oligomer;

[0495] Wherein the crosslinkable monomer or crosslinkable capping agent is reactive with the at least one aromatic diamine or the at least one di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent, and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive polyamideimide oligomer.

[0496] 24. The manufacturing method according to technical solution 23, wherein the temperature and time sufficient to prepare the reactive polyamideimide oligomer are about 140 °C to about 220 °C for about 1 minute to about 120 minutes.

[0497] 25. The manufacturing method according to technical solutions 23, 24 or 26, wherein the polar solvent is at least one of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, 1,2-dichlorobenzene, 1,2,4-trichlorobenzene or sulfolane.

[0498] 26. The manufacturing method according to any one of technical solutions 23, 24, 25 to 27, which further comprises removing the polar solvent from the polyamide amic acid oligomer before heating the reactive polyamide amic acid oligomer at a temperature and for a time sufficient to prepare the reactive polyamideimide oligomer.

[0499] 27. The manufacturing method according to technical solution 23, wherein the temperature and time sufficient to prepare the reactive polyamideimide oligomer are about 220 °C to about 300 °C for about 1 minute to about 120 minutes.

[0500] 28. The manufacturing method according to any one of technical solutions 23 to 27, wherein the method further comprises adding toluene to the reactive polyamide amic acid oligomer and azeotropically distilling toluene and water.

[0501] 29. The manufacturing method according to any one of technical solutions 23 to 27, wherein the method further comprises heating the reactive polyamide amic acid oligomer in the presence of acetic anhydride and a catalytic amount of tertiary amine.

[0502] 30. The manufacturing method according to any one of technical solutions 23 to 27, wherein the method further comprises microwave irradiating the reactive polyamide amic acid oligomer.

[0503] 31. The manufacturing method according to any one of technical solutions 23 to 30, wherein the copolymerization is carried out in the presence of a phosphorylating agent and a catalytic amount of salt.

[0504] 32. A method for manufacturing a reactive polyamideimide oligomer according to any one of technical solutions 1 to 22, the method comprising:

[0505] in water or C1-4 Heating at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or a functional equivalent thereof, and at least one crosslinkable monomer or crosslinkable capping agent in the presence of at least one alcohol at a temperature and for a time sufficient to form at least one reactive ammonium carboxylate salt;

[0506] Optionally removing excess water or C 1-4 alcohol; and

[0507] Heating the reactive ammonium carboxylate salt at a temperature and for a time sufficient to form the reactive polyamideimide oligomer;

[0508] Wherein the crosslinkable monomer or crosslinkable capping agent is reactive with the at least one aromatic diamine or the at least one di-, tri- or tetra-functional aromatic carboxylic acid or a functional equivalent thereof and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive polyamideimide oligomer.

[0509] 33. The method according to claim 32, the method comprising reactive extrusion of the reactive ammonium carboxylate salt at a temperature and for a time sufficient to form the reactive polyamideimide oligomer.

[0510] 34. The method according to claim 32, the method comprising dissolving the reactive ammonium carboxylate salt in a polar solvent before heating at a temperature, pressure and for a time sufficient to form the reactive polyamideimide oligomer.

[0511] 35. A method for manufacturing a reactive polyamideimide oligomer according to any one of claims 1 to 22, the method comprising reactive extrusion of at least one aromatic diamine or an activated derivative thereof, at least one aromatic di-, tri- or tetra-functional carboxylic acid or a functional equivalent thereof, and at least one crosslinkable monomer or crosslinkable capping agent at a temperature and for a time sufficient to prepare the reactive polyamideimide oligomer;

[0512] Wherein the crosslinkable monomer or crosslinkable capping agent is reactive with at least one aromatic diamine or at least one di-, tri- or tetra-functional aromatic carboxylic acid or a functional equivalent thereof and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive polyamideimide oligomer.

[0513] 36. The manufacturing method according to claim 35, wherein the reactive extrusion is carried out in the presence of a polar solvent and the polar solvent is removed by distillation during the reactive extrusion.

[0514] 37. The manufacturing method according to claim 35 or 36, wherein the reactive extrusion is carried out in the presence of an acidic catalyst.

[0515] 38. The manufacturing method according to technical solution 37, wherein the acidic catalyst is acetic acid, and the acetic acid is removed by distillation during the reactive extrusion.

[0516] 39. The manufacturing method according to any one of technical solutions 35 to 38, wherein the reactive extrusion is carried out in the presence of acetic anhydride, and the acetic anhydride is removed by distillation during the reactive extrusion.

[0517] 40. The manufacturing method according to any one of technical solutions 35 to 39, wherein the reactive extrusion is carried out in a melt extruder having a plurality of preset heating zones equipped with exhaust ports.

[0518] 41. A blend composition comprising a reactive polyamideimide oligomer according to any one of technical solutions 1 to 22 and a thermoplastic polymer.

[0519] 42. A powder coating composition comprising a reactive polyamideimide oligomer according to any one of technical solutions 1 to 22.

[0520] 43. A reactive adhesive composition comprising a reactive polyamideimide oligomer according to any one of technical solutions 1 to 22.

[0521] 44. A high-temperature elastomer composition prepared by heating a reactive polyamideimide oligomer according to any one of technical solutions 1 to 22 at a temperature and for a time sufficient to crosslink the reactive polyamideimide oligomer.

[0522] 45. A high-temperature foam comprising a reactive polyamideimide oligomer according to any one of technical solutions 1 to 22.

[0523] 46. A method of compounding a reactive polyamideimide oligomer according to any one of technical solutions 1 to 22, which comprises mixing the reactive polyamideimide oligomer with at least one other material at a temperature and for a time sufficient to melt but not crosslink the reactive polyamideimide oligomer.

[0524] 47. A method of manufacturing an article, the method comprising heating a reactive polyamideimide oligomer according to any one of technical solutions 1 to 22 at a sufficient temperature and for a sufficient time to shape and crosslink the reactive polyamideimide oligomer.

[0525] 48. The manufacturing method according to technical solution 47, wherein the sufficient temperature and time are about 300 to about 450 °C for about 1 to about 60 minutes.

[0526] 49. The manufacturing method according to claim 47 or 48, wherein the method is additive manufacturing, fiber-reinforced composite manufacturing, pultrusion, fiber spinning, compression molding, injection molding, reaction injection molding, blow molding, rotational molding, transfer molding, foam molding, thermoforming, casting, solution casting, or forging.

[0527] 50. An article manufactured by the method according to any one of claims 47 to 49.

[0528] 51. An article comprising a reactive polyamide-imide oligomer according to any one of claims 1 to 22.

[0529] 52. The article according to claim 51, wherein the reactive polyamide-imide oligomer is crosslinked.

[0530] 53. The manufacturing method according to any one of claims 47 to 49, wherein the method is fiber-reinforced composite manufacturing.

[0531] 54. The method according to claim 53, the method comprising heating at least one layer of fiber fabric and at least one layer of reactive polyamide-imide oligomer in the form of powder or film at a sufficient temperature, pressure, and time to melt the reactive polyamide-imide oligomer, impregnate the fiber fabric, and crosslink the reactive polyamide-imide oligomer to form a fiber-reinforced composite.

[0532] 55. The method according to claim 53, the method comprising:

[0533] impregnating at least one layer of fiber fabric with a solution of reactive polyamide-imide oligomer dissolved in a polar solvent;

[0534] removing the polar solvent under reduced pressure; and

[0535] heating at a sufficient temperature, pressure, and time to crosslink the reactive polyamide-imide oligomer and form a fiber-reinforced composite.

[0536] 56. A fiber-reinforced composite manufactured by the method according to any one of claims 53 to 55.

[0537] 57. A fiber-reinforced composite comprising a reactive polyamide-imide oligomer according to any one of claims 1 to 22.

[0538] 58. The fiber-reinforced composite according to claim 57, wherein the reactive polyamide-imide oligomer is crosslinked.

[0539] 59. The fiber-reinforced composite according to claim 57, wherein the composite is a multi-layer carbon-reinforced composite.

[0540] 60. The manufacturing method according to any one of technical solutions 47 to 49, wherein the method is pultrusion for manufacturing unidirectional tape.

[0541] 61. A unidirectional tape prepared by the method according to technical solution 60.

[0542] 62. A unidirectional tape comprising a reactive polyamideimide oligomer according to any one of technical solutions 1 to 22.

[0543] 63. The unidirectional tape according to technical solution 62, wherein the reactive polyamideimide oligomer is crosslinked.

[0544] 64. The manufacturing method according to any one of technical solutions 47 to 49, wherein the method is solution spinning or melt spinning of fibers.

[0545] 65. A fiber manufactured by the method according to technical solution 64.

[0546] 66. A fiber comprising a reactive polyamideimide oligomer according to any one of technical solutions 1 to 22.

[0547] 67. The fiber according to technical solution 66, wherein the reactive polyamideimide oligomer is crosslinked.

[0548] 68. The manufacturing method according to any one of technical solutions 47 to 49, wherein the method is additive manufacturing.

[0549] 69. The manufacturing method according to technical solution 68, wherein the method is fused filament fabrication, the method comprising extruding the reactive polyamideimide oligomer in adjacent horizontal layers such that there is an interface between each polyamideimide oligomer layer, and exposing the layers to heat at a temperature and for a time sufficient to crosslink the reactive polyamideimide oligomer and form an article.

[0550] 70. The manufacturing method according to technical solution 68, wherein the method is selective laser sintering, the method comprising selectively sintering and crosslinking particles of the reactive polyamideimide oligomer with a laser to form an article.

[0551] 71. The manufacturing method according to technical solution 68, wherein the method is directed energy deposition (DED) or laser engineered net shaping (LENS).

[0552] 72. An article manufactured by the method according to any one of technical solutions 68 to 71.

[0553] 73. An additive manufacturing article comprising a reactive polyamideimide oligomer according to any one of Technical Solutions 1 to 22.

[0554] 74. The additive manufacturing article according to Technical Solution 73, wherein the reactive polyamideimide oligomer is crosslinked.

[0555] 75. The manufacturing method according to any one of Technical Solutions 47 to 49, wherein the method is solution casting and includes:

[0556] Casting a solution of a reactive polyamideimide oligomer dissolved in a polar solvent onto a mold;

[0557] Removing the polar solvent to form a reactive polyamideimide oligomer film; and

[0558] Heating the polyamideimide oligomer film at a temperature and for a time sufficient to crosslink the polyamideimide oligomer and form a flexible film.

[0559] 76. A flexible film manufactured by the solution casting method according to Technical Solution 75.

[0560] 77. A flexible film comprising a reactive polyamideimide oligomer according to any one of Technical Solutions 1 to 22.

[0561] 78. The flexible film according to Technical Solution 77, wherein the reactive polyamideimide oligomer is crosslinked.

[0562] 79. The flexible film according to any one of Technical Solutions 76 to 78, wherein the flexible film exhibits at least one of the following:

[0563] Measured by differential scanning calorimetry at a heating rate of 10 °C / min under N 2 , the glass transition temperature (Tg) is about 280 to about 310 °C;

[0564] Measured by dynamic mechanical thermal analysis at a heating rate of 10 °C / min and an oscillation rate of 1 Hz under N 2 , the storage modulus (E') is about 2.2 to about 3.4 GPa;

[0565] The Young's modulus is about 3.0 to about 3.8 GPa, the fracture strength is about 130 to about 160 MPa, or the fracture strain is about 10 to 80%, all measured at 25 °C.

[0566] 80. The manufacturing method according to any one of Technical Solutions 47 to 49, wherein the method is injection molding.

[0567] 81. An injection molded article, which is manufactured by the method according to Technical Solution 80.

[0568] 82. An injection molded article, which comprises a reactive polyamideimide oligomer according to any one of Technical Solutions 1 to 22.

[0569] 83. The additive manufactured article according to Technical Solution 82, wherein the reactive polyamideimide oligomer is crosslinked.

[0570] 84. A reactive polyamide amic acid oligomer, which comprises units derived from: at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or its functional equivalent, and at least one crosslinkable monomer or crosslinkable capping agent,

[0571] wherein the crosslinkable monomer or crosslinkable capping agent is reactive with the at least one aromatic diamine or the at least one di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive polyamide amic acid oligomer; and

[0572] wherein the number average molecular weight (M n ) of the reactive polyamide amic acid oligomer is calculated using the Carothers equation to be about 1000 to about 10000 g / mol.

[0573] 85. The reactive polyamide amic acid oligomer according to Technical Solution 84, wherein 0% to about 20% of the amic acid groups are imidized.

[0574] 86. The reactive polyamide amic acid oligomer according to Technical Solution 84 or 85, wherein the crosslinkable monomer or crosslinkable capping agent has an unreacted functional group capable of thermal chain extension and crosslinking after the formation of the reactive polyamideimide oligomer.

[0575] 87. The reactive polyamide amic acid oligomer according to any one of Technical Solutions 84 to 86, wherein the at least one crosslinkable monomer or crosslinkable capping agent is at least one crosslinkable capping agent.

[0576] 88. The reactive polyamide amic acid oligomer according to any one of Technical Solutions 84 to 87, wherein the at least one aromatic diamine is two aromatic diamines.

[0577] 89. The reactive polyamide amic acid oligomer according to any one of Technical Solutions 84 to 88, wherein the at least one aromatic di-, tri- or tetra-functional carboxylic acid or its functional equivalent is two aromatic di-, tri- or tetra-functional carboxylic acids or their functional equivalents.

[0578] 90. The reactive polyamide amic acid oligomer according to any one of technical solutions 84 to 89 is prepared by a method comprising simultaneously stepwise polymerizing the at least one aromatic diamine, the at least one aromatic di-, tri- or tetra-functional carboxylic acid or its functional equivalent, and the at least one crosslinkable monomer or crosslinkable capping agent.

[0579] 91. The reactive polyamide amic acid oligomer according to any one of technical solutions 84 to 90, wherein the aromatic diamine is at least one of the following:

[0580]

[0581] 92. The reactive polyamide amic acid oligomer according to any one of technical solutions 84 to 91, wherein the aromatic diamine is at least one of 1,3-benzenediamine, 4,4'-oxydianiline or 3,4'-oxydianiline.

[0582] 93. The reactive polyamide amic acid oligomer according to any one of technical solutions 84 to 92, wherein the di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent is at least one of the following:

[0583]

[0584] 94. The reactive polyamide amic acid oligomer according to any one of technical solutions 84 to 93, wherein the di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent is at least one of trimellitic anhydride, 4-chlorocarbonyl phthalic anhydride, phthalic anhydride, isophthaloyl chloride, pyromellitic dianhydride or biphenyltetracarboxylic dianhydride.

[0585] 95. The reactive polyamide amic acid oligomer according to any one of technical solutions 84 to 94, wherein the at least one unreacted functional group is at least one of acetylene, methylacetylene, phenylacetylene, ketoacetylene, propargyl ether, norbornene, maleimide, cyanate ester, phthalonitrile, benzocyclobutene, biphenyl or benzoxazine.

[0586] 96. The reactive polyamide amic acid oligomer according to any one of technical solutions 84 to 95, wherein the crosslinkable monomer or crosslinkable capping agent is at least one of the following:

[0587]

[0588]

[0589] 97. The reactive polyamide amic acid oligomer according to any one of technical solutions 84 to 96, wherein the crosslinkable monomer or crosslinkable capping agent is at least one of 4-ethynylphthalic anhydride, 4-methylethynylphthalic anhydride, 4-phenylethynylphthalic anhydride (PEPA), or 4,4'-(ethyne-1,2-diyl)diphthalic anhydride.

[0590] 98. The reactive polyamide amic acid oligomer according to any one of technical solutions 84 to 97, which comprises two crosslinkable monomers or crosslinkable capping agents having reactivity in different temperature ranges.

[0591] 99. The reactive polyamide amic acid oligomer according to any one of technical solutions 84 to 98, which further comprises units derived from at least one non-crosslinkable capping agent, wherein the non-crosslinkable capping agent is reactive with the at least one aromatic diamine or at least one di-, tri-, or tetra-functional aromatic carboxylic acid or its functional equivalent.

[0592] 100. The reactive polyamide amic acid oligomer according to technical solution 99, wherein the non-crosslinkable capping agent is at least one of benzoic acid, benzoyl chloride, phthalic anhydride, or aniline.

[0593] 101. A reactive polyamide amic acid oligomer, which comprises units derived from:

[0594] At least one aromatic diamine selected from the following:

[0595]

[0596] At least one di-, tri-, or tetra-functional aromatic carboxylic acid or its functional equivalent selected from the following:

[0597] And at least one crosslinkable monomer or crosslinkable capping agent selected from the following:

[0598]

[0599]

[0600] 102. A reactive polyamide amic acid oligomer, which comprises units derived from:

[0601] At least one aromatic diamine selected from 1,3-phenylenediamine, 4,4'-oxydianiline, or 3,4'-oxydianiline;

[0602] At least one di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent selected from trimellitic anhydride, 4-chlorocarbonyl phthalic anhydride, isophthalic anhydride, isophthaloyl chloride, pyromellitic dianhydride or biphenyltetracarboxylic dianhydride; and

[0603] A crosslinkable monomer or crosslinkable capping agent selected from at least one of 4-ethynylphthalic anhydride, 4-methylethynylphthalic anhydride, 4-phenylethynylphthalic anhydride (PEPA) or 4,4'-(ethyne-1,2-diyl)diphthalic anhydride.

[0604] 103. A method for manufacturing a reactive polyamide amic acid oligomer according to any one of technical solutions 84 to 102, the method comprising:

[0605] Copolymerizing at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or its functional equivalent, and at least one crosslinkable monomer or crosslinkable capping agent in the presence of a polar solvent to form the reactive polyamide amic acid oligomer;

[0606] Wherein the crosslinkable monomer or crosslinkable capping agent is reactive with the at least one aromatic diamine or the at least one di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent, and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive polyamide amic acid oligomer.

[0607] 104. The manufacturing method according to technical solution 103, wherein the polar solvent is at least one of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, 1,2-dichlorobenzene, 1,2,4-trichlorobenzene or sulfolane.

[0608] 105. The manufacturing method according to technical solution 103 or 104, which further comprises separating the reactive polyamide amic acid oligomer from the polar solvent.

[0609] 106. A blend composition comprising the reactive polyamide amic acid oligomer according to any one of technical solutions 84 to 102 and a thermoplastic polymer.

[0610] 107. A powder coating composition comprising the reactive polyamide amic acid oligomer according to any one of technical solutions 84 to 102.

[0611] 108. A reactive adhesive composition comprising the reactive polyamide amic acid oligomer according to any one of technical solutions 84 to 102.

[0612] 109. A high-temperature foam comprising a reactive polyamide amic acid oligomer according to any one of technical solutions 84 to 102.

[0613] 110. A method of blending a reactive polyamide amic acid oligomer according to any one of technical solutions 84 to 102, which comprises mixing the reactive polyamide amic acid oligomer with at least one other material at a temperature and for a time sufficient to imidize but not crosslink the reactive polyamide amic acid oligomer.

[0614] 111. A method of manufacturing an article, the method comprising heating a reactive polyamide amic acid oligomer according to any one of technical solutions 84 to 102 at a sufficient temperature and for a sufficient time to imidize, shape, and crosslink the reactive polyamide amic acid oligomer.

[0615] 112. The manufacturing method according to technical solution 111, wherein the sufficient temperature and time are about 300 to about 400 °C for about 10 to about 60 minutes.

[0616] 113. The manufacturing method according to technical solution 110 or 111, wherein the method is additive manufacturing, fiber-reinforced composite manufacturing, pultrusion, fiber spinning, compression molding, injection molding, reaction injection molding, blow molding, rotational molding, transfer molding, foam molding, thermoforming, casting, solution casting, or forging.

[0617] 114. An article manufactured by the method according to any one of technical solutions 111 to 113.

[0618] 115. An article comprising a reactive polyamide amic acid oligomer according to any one of technical solutions 84 to 102.

[0619] 116. The manufacturing method according to any one of technical solutions 111 to 113, wherein the method is fiber-reinforced composite manufacturing.

[0620] 117. The method according to technical solution 116, the method comprising heating at least one layer of fiber fabric and at least one layer of reactive polyamide amic acid oligomer in the form of a powder or a film at a sufficient temperature, pressure, and time to imidize the reactive polyamide amic acid oligomer, impregnate the fiber fabric, and crosslink to form a fiber-reinforced composite.

[0621] 118. The method according to technical solution 116, the method comprising:

[0622] impregnating at least one layer of fiber fabric with a solution of a reactive polyamide amic acid oligomer dissolved in a polar solvent;

[0623] removing the polar solvent under reduced pressure, and

[0624] Heat at a temperature, pressure and time sufficient to imidize and crosslink the reactive polyamide amic acid oligomer to form a fiber-reinforced composite material.

[0625] 119. A fiber-reinforced composite material, which is manufactured by the method according to any one of Technical Solutions 116 to 118.

[0626] 120. A fiber-reinforced composite material, which contains the reactive polyamide amic acid oligomer according to any one of Technical Solutions 84 to 102.

[0627] 121. The fiber-reinforced composite material according to Technical Solution 120, wherein the composite material is a multi-layer carbon-reinforced composite material.

[0628] 122. The manufacturing method according to any one of Technical Solutions 111 to 113, wherein the method is pultrusion for manufacturing a unidirectional tape.

[0629] 123. A unidirectional tape, which is prepared by the method according to Technical Solution 122.

[0630] 124. A unidirectional tape, which includes the reactive polyamide amic acid oligomer according to any one of Technical Solutions 84 to 102.

[0631] 125. The manufacturing method according to any one of Technical Solutions 111 to 113, wherein the method is solution spinning or melt spinning of fibers.

[0632] 126. A fiber, which is manufactured by the method according to Technical Solution 125.

[0633] 127. A fiber, which contains the reactive polyamide amic acid oligomer according to any one of Technical Solutions 84 to 102.

[0634] 128. The manufacturing method according to any one of Technical Solutions 111 to 113, wherein the method is additive manufacturing.

[0635] 129. The manufacturing method according to Technical Solution 128, wherein the method is fused filament fabrication, and the method includes extruding the reactive polyamide amic acid oligomer in adjacent horizontal layers such that there is an interface between each reactive polyamide amic acid oligomer layer, and exposing the layers to heat at a temperature and for a time sufficient to imidize and crosslink the reactive polyamide amic acid oligomer and form the article.

[0636] 130. The manufacturing method according to technical solution 128, wherein the method is selective laser sintering, and the method includes selectively sintering, imidizing, and crosslinking particles of the reactive polyamide amic acid oligomer with a laser to form an article.

[0637] 131. The manufacturing method according to technical solution 128, wherein the method is directed energy deposition (DED) or laser engineered net shaping (LENS).

[0638] 132. An article manufactured by the method according to any one of technical solutions 128 to 131.

[0639] 133. An additive manufactured article comprising a reactive polyamide amic acid oligomer according to any one of technical solutions 84 to 102.

[0640] 134. The manufacturing method according to any one of technical solutions 111 to 113, wherein the method is solution casting and includes:

[0641] Casting a solution of the reactive polyamide amic acid oligomer dissolved in a polar solvent onto a mold;

[0642] Removing the solvent to form a reactive polyamide amic acid oligomer film; and

[0643] Heating the reactive polyamide amic acid oligomer film at a temperature and for a time sufficient to imidize and crosslink the reactive polyamide amic acid oligomer and form a flexible film.

[0644] 135. A flexible film manufactured by the solution casting method according to technical solution 134.

[0645] 136. A flexible film comprising a reactive polyamide amic acid oligomer according to any one of technical solutions 84 to 102.

[0646] 137. The manufacturing method according to any one of technical solutions 111 to 113, wherein the method is injection molding.

[0647] 138. An injection molded article manufactured by the method according to technical solution 137.

[0648] 139. An injection molded article comprising a reactive polyamide amic acid oligomer according to any one of technical solutions 84 to 102.

[0649] 140. The manufacturing method according to any one of technical solutions 111 to 113, wherein the method is blow molding.

[0650] 141. A reactive carboxylic acid ammonium salt formed by a method comprising the following:

[0651] In the presence of C 1-4 alcohol, at a temperature and for a time sufficient to form a reactive ammonium carboxylate salt, heat at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or a functional equivalent thereof, and at least one crosslinkable monomer or crosslinkable end-capping agent;

[0652] Remove the excess C 1-4 alcohol;

[0653] wherein the crosslinkable monomer or crosslinkable end-capping agent is reactive with the at least one aromatic diamine or the at least one di-, tri- or tetra-functional aromatic carboxylic acid or a functional equivalent thereof, and has at least one unreacted functional group capable of chain extension and crosslinking after formation of the reactive ammonium carboxylate salt.

[0654] 142. The reactive ammonium carboxylate salt according to claim 141, wherein the crosslinkable monomer or crosslinkable end-capping agent has one unreacted functional group capable of thermal chain extension and crosslinking after formation of the reactive ammonium carboxylate salt.

[0655] 143. The reactive ammonium carboxylate salt according to claim 141 or 142, wherein the at least one crosslinkable monomer or crosslinkable end-capping agent is at least one crosslinkable end-capping agent.

[0656] 144. The reactive ammonium carboxylate salt according to any one of claims 141 to 143, wherein the at least one aromatic diamine is two aromatic diamines.

[0657] 145. The reactive ammonium carboxylate salt according to any one of claims 141 to 144, wherein the at least one aromatic di-, tri- or tetra-functional carboxylic acid or a functional equivalent thereof is two aromatic di-, tri- or tetra-functional carboxylic acids or a functional equivalent thereof.

[0658] 146. The reactive ammonium carboxylate salt according to any one of claims 141 to 145, wherein the aromatic diamine is at least one of the following:

[0659]

[0660] 147. The reactive ammonium carboxylate salt according to any one of claims 141 to 146, wherein the aromatic diamine is at least one of 1,3-phenylenediamine, 4,4'-oxydianiline or 3,4'-oxydianiline.

[0661] 148. The reactive ammonium carboxylate salt according to any one of claims 141 to 147, wherein the di-, tri- or tetra-functional aromatic carboxylic acid or a functional equivalent thereof is at least one of the following:

[0662]

[0663] 149. The reactive ammonium carboxylate according to any one of technical solutions 141 to 148, wherein the di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent is at least one of trimellitic anhydride, phthalic anhydride, pyromellitic dianhydride or biphenyltetracarboxylic dianhydride.

[0664] 150. The reactive ammonium carboxylate according to any one of technical solutions 141 to 149, wherein the unreacted functional group is at least one of acetylene, methylacetylene, phenylacetylene, ketoacetylene, propargyl ether, norbornene, maleimide, cyanate ester, phthalonitrile, benzocyclobutene, biphenyl or benzoxazine.

[0665] 151. The reactive ammonium carboxylate according to any one of technical solutions 141 to 150, wherein the crosslinkable monomer or crosslinkable capping agent is at least one of the following:

[0666]

[0667]

[0668] 152. The reactive ammonium carboxylate according to any one of technical solutions 141 to 151, wherein the crosslinkable monomer or crosslinkable capping agent is at least one of 4-ethynylphthalic anhydride, 4-methyl-ethynylphthalic anhydride, 4-phenyl-ethynylphthalic anhydride (PEPA) or 4,4'-(ethyne-1,2-diyl)diphthalic anhydride.

[0669] 153. The reactive ammonium carboxylate according to any one of technical solutions 141 to 152, which comprises two crosslinkable monomers or crosslinkable capping agents that are reactive in different temperature ranges.

[0670] 154. The reactive ammonium carboxylate according to any one of technical solutions 141 to 153, which further comprises units derived from at least one non-crosslinkable capping agent, wherein the non-crosslinkable capping agent is reactive with at least one aromatic diamine or at least one di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent.

[0671] 155. The reactive ammonium carboxylate according to technical solution 154, wherein the non-crosslinkable capping agent is at least one of benzoic acid, benzoyl chloride, phthalic anhydride or aniline.

[0672] 156. The reactive ammonium carboxylate according to any one of technical solutions 141 to 155, wherein the reactive ammonium carboxylate has a melt complex viscosity of about 1 to about 100 Pa·s between about 80 °C and about 120 °C, and the melt complex viscosity is at N 2Next, it is measured by oscillatory shear rheology between parallel plates at a heating rate of 10 °C / minute, a frequency of 2 radians / second, and a strain of 0.03% to 1.0%.

[0673] 157. A reactive ammonium carboxylate salt comprising units derived from:

[0674] At least one aromatic diamine selected from the following:

[0675]

[0676] At least one di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent selected from the following:

[0677] And at least one crosslinkable monomer or crosslinkable capping agent selected from the following:

[0678]

[0679]

[0680] 158. A reactive ammonium carboxylate salt comprising units derived from: an aromatic diamine selected from at least one of 1,3-phenylenediamine, 4,4'-oxydianiline or 3,4'-oxydianiline; a di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent selected from at least one of trimellitic anhydride, 4-chlorobenzoyl chloride, phthalic anhydride, isophthaloyl chloride, pyromellitic dianhydride or biphenyltetracarboxylic dianhydride; and a crosslinkable monomer or crosslinkable capping agent selected from at least one of 4-ethynylphthalic anhydride, 4-methyl-ethynylphthalic anhydride, 4-phenylethynylphthalic anhydride (PEPA) or 4,4'-(ethyne-1,2-diyl)diphthalic anhydride.

[0681] 159. A method for producing a reactive ammonium carboxylate salt, the method comprising:

[0682] In the presence of C 1-4 Alcohol, heating at least one aromatic diamine, at least one aromatic di-, tri- or tetra-carboxylic acid or its functional equivalent, and at least one crosslinkable monomer or crosslinkable capping agent at a temperature and for a time sufficient to form the reactive ammonium carboxylate salt;

[0683] Removing excess C 1-4 Alcohol;

[0684] Wherein the crosslinkable monomer or crosslinkable capping agent is reactive with the at least one aromatic diamine or the at least one di-, tri- or tetra-functional aromatic carboxylic acid or its functional equivalent and has at least one unreacted functional group capable of chain extension and crosslinking after the formation of the reactive ammonium carboxylate salt.

[0685] 160. A method of mixing a reactive ammonium carboxylate according to any one of technical solutions 141 to 158, which comprises mixing the reactive ammonium carboxylate with at least one other material at a temperature, pressure and time sufficient to prepare but not crosslink a reactive polyamideimide oligomer.

[0686] 161. A method of manufacturing an article, the method comprising heating a reactive ammonium carboxylate according to any one of technical solutions 141 to 158 at a sufficient temperature, pressure and time to prepare, shape and crosslink a reactive polyamideimide oligomer.

[0687] 162. The manufacturing method according to technical solution 161, wherein the sufficient temperature, pressure and time are about 300 °C to about 400 °C, 0 to about 300 MPa and about 10 to about 60 minutes.

[0688] 163. The manufacturing method according to technical solution 161 or 162, wherein the method is fiber-reinforced composite manufacturing, pultrusion, compression molding, injection molding or solution casting.

[0689] 164. An article manufactured by the method according to any one of technical solutions 161 to 163.

[0690] 165. The manufacturing method according to any one of technical solutions 161 to 163, wherein the method is fiber-reinforced composite manufacturing.

[0691] 166. The method according to technical solution 165, the method comprising heating at least one layer of fiber fabric and at least one layer of reactive ammonium carboxylate in the form of a powder or film at a temperature, pressure and time sufficient to impregnate the fiber fabric with the reactive ammonium carboxylate and to prepare and crosslink a reactive polyamideimide oligomer to form a fiber-reinforced composite.

[0692] 167. The method according to technical solution 165, the method comprising: impregnating at least one layer of fiber fabric with a solution of reactive ammonium carboxylate dissolved in a polar solvent; removing the polar solvent under reduced pressure; and heating at a temperature, pressure and time sufficient to polymerize and crosslink the reactive polyamideimide oligomer to form a fiber-reinforced composite.

[0693] 168. A fiber-reinforced composite manufactured by the method according to any one of technical solutions 165 to 167.

[0694] 169. The fiber-reinforced composite according to technical solution 168, wherein the composite is a multi-layer carbon-reinforced composite.

[0695] 170. The manufacturing method according to any one of technical solutions 161 to 163, wherein the method is solution casting and includes: casting a solution of a reactive ammonium carboxylate dissolved in a polar solvent onto a mold; removing the polar solvent to form a reactive ammonium carboxylate film; and heating the reactive ammonium carboxylate film at a temperature, pressure, and time sufficient to prepare and crosslink a reactive polyamideimide oligomer to form a flexible film.

[0696] 171. A flexible film manufactured by the solution casting method according to technical solution 170.

[0697] 172. The manufacturing method according to any one of technical solutions 161 to 163, wherein the method is injection molding.

[0698] 173. The manufacturing method according to any one of technical solutions 161 to 163, wherein the method is blow molding.

Claims

1. A reactive polyamideimide oligomer comprising units derived from at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or a functional equivalent thereof, and at least one crosslinkable monomer or crosslinkable capping agent; wherein the crosslinkable monomer or crosslinkable capping agent is reactive with the at least one aromatic diamine or at least one di-, tri- or tetra-functional aromatic carboxylic acid or a functional equivalent thereof and has at least one unreacted functional group capable of undergoing thermal chain extension and crosslinking after formation of the reactive polyamideimide oligomer; and wherein the number average molecular weight (M n ) of the reactive polyamideimide oligomer is calculated to be about 1,000 to about 10,000 g / mol using the Carothers equation.

2. The reactive polyamideimide oligomer according to claim 1, wherein the reactive polyamideimide oligomer is derived from a reactive polyamideamic acid oligomer intermediate by dehydration cyclization, and more than 80% and less than or equal to 100% of the amic acid groups in the reactive polyamideamic acid intermediate are imidized.

3. The reactive polyamideimide oligomer according to claim 1, wherein the reactive polyamideimide oligomer is derived from a reactive polyamideamic acid oligomer intermediate by dehydration cyclization, and greater than or equal to 20% and less than or equal to 80% of the amic acid groups in the reactive polyamideamic acid intermediate are imidized.

4. The reactive polyamideimide oligomer according to any one of claims 1 to 3, wherein the crosslinkable monomer or crosslinkable capping agent has one unreacted functional group capable of undergoing thermal chain extension and crosslinking after formation of the reactive polyamideimide oligomer.

5. The reactive polyamideimide oligomer according to any one of claims 1 to 4, wherein the at least one crosslinkable monomer or crosslinkable capping agent is at least one crosslinkable capping agent.

6. The reactive polyamideimide oligomer according to any one of claims 1 to 5, wherein the at least one aromatic diamine is two aromatic diamines.

7. The reactive polyamideimide oligomer according to any one of claims 1 to 6, wherein the at least one aromatic di-, tri- or tetra-functional carboxylic acid or a functional equivalent thereof is two aromatic di-, tri- or tetra-functional carboxylic acids or a functional equivalent thereof.

8. The reactive polyamideimide oligomer according to any one of claims 1 to 7, which is prepared by a method comprising simultaneously stepwise polymerizing at least one aromatic diamine, at least one aromatic di-, tri- or tetra-functional carboxylic acid or a functional equivalent thereof and at least one crosslinkable monomer or crosslinkable capping agent.

9. The reactive polyamideimide oligomer according to any one of claims 1 to 8, wherein the aromatic diamine is at least one of the following:

10. The reactive polyamideimide oligomer according to any one of claims 1 to 9, wherein the aromatic diamine is at least one of 1,3-phenylenediamine, 4,4'-oxydianiline and 3,4'-oxydianiline.

Images