A dynamically covalently crosslinked aromatic polyamide material and a method for producing the same

Abstract

The embodiment of the application provides a kind of dynamic covalent crosslinking aromatic polyamide material and its preparation method.Aiming at the problem that existing aromatic polyamide is prone to rigidity drop in toughening process, or processing and recycling are limited due to crosslinking, a preparation scheme for realizing performance balance through molecular structure synergistic regulation is proposed.The method is based on aromatic polyamide prepolymer terminated by amino groups at both ends, introduces 9,10-dihydroxyoctadecanedioic acid monomer of biobased origin, controls its addition amount to be 10% to 40% of the mass of the prepolymer, and controls the number average molecular weight of the prepolymer to be 2000 to 5000, to obtain a dynamic covalent crosslinking aromatic polyamide material.Thus, while maintaining the rigid skeleton of the aromatic polyamide, the material toughness and processing adaptability can be improved, the risk of phase separation and interface defect is reduced, and subsequent molding and recycling are facilitated.

Description

Technical Field

[0001] This application relates to the field of polymer materials technology, and in particular to a dynamically covalently cross-linked aromatic polyamide material and its preparation method. Background Technology

[0002] Aromatic polyamide materials are widely used in high-end manufacturing fields with stringent material performance requirements due to their excellent heat resistance, high strength, and gas barrier properties. For example, in the automotive industry, they can be used as lightweight structural components, under-hood parts, and battery pack encapsulation materials to cope with complex conditions such as high temperature, vibration, and chemical corrosion; in the electronics and electrical appliance field, they are often used as high heat-resistant printed circuit board substrates, chip encapsulation materials, and electromagnetic shielding devices to meet the stable operation requirements of electronic products in high-temperature and high-humidity environments; in the packaging industry, they can be used as high-barrier food packaging films to prevent oxygen and water vapor penetration and extend the shelf life of food.

[0003] In the prior art, the optimization of the toughness of aromatic polyamide materials mainly relies on two strategies: (1) Physical blending modification: improving toughness by incorporating elastomers (such as polyolefins, polyurethanes, etc.) into the polyamide matrix. However, due to the poor compatibility and weak interfacial bonding between the matrix and the toughening phase, such methods often result in uneven mixing, which not only has a limited toughening effect but also significantly reduces the rigidity, strength, and gas barrier properties of the material. (2) Chemical structure adjustment: introducing flexible segments (such as long-chain aliphatic dicarboxylic acids, polyether units, etc.) into the molecular backbone or constructing a permanent crosslinking network (such as using maleic anhydride groups to react with terminal amino groups to form covalent crosslinks). Although the introduction of flexible segments can improve toughness, it will destroy the regularity of the molecular chain, resulting in a decrease in the rigidity, heat resistance, and dimensional stability of the material; while the permanent crosslinking network can enhance mechanical properties, it makes the material lose its thermoplasticity, making it impossible to melt process or mechanically recycle, thus limiting its application in the circular economy.

[0004] Therefore, developing a new type of aromatic polyamide material that combines high rigidity and high toughness, and supports thermal remodeling and recycling, is key to resolving the contradiction between the manufacturing industry's demand for high-performance materials and the pressure on resources and the environment. Summary of the Invention

[0005] This invention provides a dynamically covalently crosslinked aromatic polyamide material and its preparation method. The aromatic polyamide material is prepared by polymerizing a long-chain dicarboxylic acid containing hydroxyl groups with an aromatic polyamide prepolymer with amino-terminated ends, thereby synergistically optimizing the strength, toughness and thermosetting properties of the aromatic polyamide material.

[0006] This invention provides a method for preparing a dynamically covalently crosslinked aromatic polyamide material, comprising the following steps: polymerizing a raw material containing a long-chain dicarboxylic acid with hydroxyl groups and an aromatic polyamide prepolymer with amino-terminated ends to obtain the aromatic polyamide material; wherein, the long-chain dicarboxylic acid containing hydroxyl groups is 9,10-dihydroxyoctadecanoic acid; the mass ratio of the long-chain dicarboxylic acid containing hydroxyl groups to the mass ratio of the aromatic polyamide prepolymer with amino-terminated ends is 10% to 40%; and the number average molecular weight of the aromatic polyamide prepolymer with amino-terminated ends is 2000 to 5000.

[0007] According to one embodiment of the present invention, the mass ratio of the long-chain dicarboxylic acid containing hydroxyl groups to the mass ratio of the amino-terminated aromatic polyamide prepolymer is 15% to 30%.

[0008] According to one embodiment of the present invention, the preparation process of the long-chain dicarboxylic acid containing hydroxyl groups includes: subjecting an unsaturated long-chain dicarboxylic acid to an oxidation reaction in the presence of an alkali metal hydroxide and an oxidant to obtain an oxidation product; and acidifying the oxidation product with a first inorganic acid to obtain the long-chain dicarboxylic acid containing hydroxyl groups.

[0009] According to one embodiment of the present invention, the unsaturated long-chain dicarboxylic acid is obtained from vegetable oil through hydrolysis and autodecomposition reaction; wherein, the vegetable oil includes one or more of rubber seed oil, tallow tree oil, and high-oleic rapeseed oil.

[0010] According to one embodiment of the present invention, the unsaturated long-chain dicarboxylic acid includes octadecano-9-enediol.

[0011] According to one embodiment of the present invention, the alkali metal hydroxide includes one or more of potassium hydroxide and sodium hydroxide.

[0012] According to one embodiment of the present invention, the oxidant comprises potassium permanganate.

[0013] According to one embodiment of the present invention, the oxidation reaction is carried out at a temperature of 0°C to 10°C for a time of 10 min to 30 min.

[0014] According to one embodiment of the present invention, the first inorganic acid includes concentrated hydrochloric acid.

[0015] According to one embodiment of the present invention, the amino-terminated aromatic polyamide prepolymer is polymerized by polycondensation reaction of raw materials including diamine and diacid, wherein the diacid includes aromatic diacid and the diamine includes aromatic diamine.

[0016] According to one embodiment of the present invention, in the polycondensation reaction, the total number of functional groups N of the carboxyl groups in the diacid is...COOH The total number of functional groups N of the amino groups in the diamine NH2 The equivalence ratio r ranges from 0.8 to 0.93.

[0017] According to one embodiment of the present invention, the diamine includes one or more of the following: α,ω-linear aliphatic diamines having 4 to 14 carbon atoms, m-phenylenediamine, p-phenylenediamine, 1,4-cyclohexanedimethylamine, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 4,4'-diaminodicyclohexylmethane, and 4,4'-isopropyldicyclohexylamine.

[0018] According to one embodiment of the present invention, the dicarboxylic acid includes one or more of the following: α,ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms, isophthalic acid, terephthalic acid, 2,5-furandicarboxylic acid, phenylmalonic acid, terephthalic acid, biphenyl dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and 2,6-naphthalenedicarboxylic acid.

[0019] According to one embodiment of the present invention, the polymerization process includes: mixing the raw material of the long-chain dicarboxylic acid containing hydroxyl groups with the raw material of the aromatic polyamide prepolymer with amino-terminated ends to obtain a mixture; subjecting the mixture to a polycondensation reaction and an ester exchange reaction to obtain the aromatic polyamide material.

[0020] According to one embodiment of the present invention, the polycondensation reaction includes an amidation polycondensation reaction and an esterification polycondensation reaction.

[0021] According to one embodiment of the present invention, the temperature of the polycondensation reaction is 170°C to 230°C.

[0022] According to one embodiment of the present invention, the temperature of the transesterification reaction is 200°C to 230°C.

[0023] According to one embodiment of the present invention, the raw material further includes a first antioxidant, which includes one or more of the following: tris[2,4-di-tert-butylphenyl]phosphite (168), N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine (1098), pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (1010), octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (1076), and 3,5-di-tert-butyl-4-hydroxybenzyl diethylphosphonate (1222).

[0024] In another aspect, the present invention provides an aromatic polyamide material, which is prepared according to the method for preparing the aromatic polyamide material.

[0025] The implementation of this invention has at least the following beneficial effects:

[0026] By combining rigid, amino-terminated aromatic polyamide prepolymers with flexible, hydroxyl-containing long-chain dicarboxylic acids, a dynamic covalent cross-linked network is formed. This not only retains the high strength and high modulus properties of aromatic polyamides but also enhances the toughness of aromatic polyamide materials by introducing flexible segments. At the same time, the dynamic covalent cross-linked network can achieve topological rearrangement when heated, giving aromatic polyamide materials the ability to be thermally reshaped.

[0027] Meanwhile, by adjusting the addition ratio of long-chain dicarboxylic acids containing hydroxyl groups and the number-average molecular weight of aromatic polyamide prepolymers with amino-terminated ends, the crosslinking density and flexible segment content of the material are optimized, ultimately achieving a synergistic effect of high strength, high toughness and recyclability of dynamically covalently crosslinked aromatic polyamide materials. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. The specific embodiments listed below are merely descriptions of the principles and features of this invention, and the examples given are only for explaining this invention and are not intended to limit the scope of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0029] This invention provides a method for preparing a dynamically covalently crosslinked aromatic polyamide material, comprising the following steps: polymerizing a raw material containing a long-chain dicarboxylic acid with hydroxyl groups and an aromatic polyamide prepolymer with amino-terminated ends to obtain the aromatic polyamide material; wherein the long-chain dicarboxylic acid containing hydroxyl groups is 9,10-dihydroxyoctadecanoic acid; the mass ratio of the long-chain dicarboxylic acid containing hydroxyl groups to the mass ratio of the aromatic polyamide prepolymer with amino-terminated ends is 10% to 40%; and the number average molecular weight of the aromatic polyamide prepolymer with amino-terminated ends is 2000 to 5000.

[0030] According to the inventors' research, the above-mentioned method for preparing dynamically covalently cross-linked aromatic polyamide materials involves polymerizing a bi-amino-terminated aromatic polyamide prepolymer with a hydroxyl-containing long-chain dicarboxylic acid. By limiting the addition ratio of the hydroxyl-containing long-chain dicarboxylic acid and the number-average molecular weight of the bi-amino-terminated aromatic polyamide prepolymer, it is possible to improve the toughness of the material by introducing flexible long chains and cross-linking structures with the help of the hydroxyl-containing long-chain dicarboxylic acid, while retaining the advantages of high rigidity and high strength of aromatic polyamides.

[0031] Long-chain dicarboxylic acids containing hydroxyl groups possess both a flexible long-chain structure and active hydroxyl sites. The long carbon chain segments can dissipate impact energy through chain segment movement when subjected to force, thus improving the inherent brittleness of aromatic polyamides. On the one hand, the hydroxyl groups in the molecule can react with their terminal carboxyl groups to form ester crosslinking points, constructing a three-dimensional dynamic covalent network without destroying the rigid backbone of the main chain. On the other hand, the remaining free hydroxyl groups can undergo transesterification reactions with the ester bonds in the network, realizing topological rearrangement of the covalent network, forming uniformly distributed reversible ester bond crosslinking points, and endowing the material with thermal reshaping and thermal repair capabilities.

[0032] Specifically, the aforementioned long-chain dicarboxylic acid containing hydroxyl groups is 9,10-dihydroxyoctadecanoic acid.

[0033] Amino-terminated aromatic polyamide prepolymers can be defined as aromatic polyamide oligomers with amino-terminated ends, exhibiting further polycondensation reactivity. They serve as the main structural precursor, providing a high-strength, high-heat-resistance, and high-dimensional-stability structural basis. In subsequent polycondensation, they connect with long-chain diacids containing hydroxyl groups to form thermoplasticizable aromatic polyamide materials. This prepolymer occupies a supporting position in the reaction system, with its terminal amino groups acting as the main reaction sites for chain growth, enabling it to undergo polycondensation with the carboxyl groups of the diacid during the reaction.

[0034] Meanwhile, controlling the mass percentage of hydroxyl-containing long-chain dicarboxylic acids to 10%–40% of the prepolymer allows the hydroxyl-containing long-chain dicarboxylic acids to provide appropriate flexible segments and reaction sites during polymerization, reacting with themselves and the amino-terminated aromatic polyamide prepolymer to form a covalent network of appropriate density, while simultaneously creating suitable structural rearrangement conditions. Within this addition range, it avoids both incomplete dynamic network construction and limited toughness improvement due to insufficient addition, and excessive addition leading to excessive flexible segments and a significant decrease in material rigidity and strength, thus contributing to improved performance balance of dynamically covalently crosslinked aromatic polyamide materials.

[0035] Meanwhile, the number-average molecular weight of the above-mentioned amino-terminated aromatic polyamide prepolymers is controlled within the range of 2000 to 5000. This range allows for a moderate concentration of terminal amino groups in the amino-terminated aromatic polyamide prepolymers, enabling efficient and stable amidation polycondensation reactions with hydroxyl-containing long-chain dicarboxylic acids. This avoids both excessively low molecular weight leading to rapid reactions, localized gel agglomeration, and deterioration of the covalent network toughness, and excessively high molecular weight causing molecular chain steric hindrance and insufficient cross-linking reactions. This ensures the uniform and complete construction of the dynamic covalent network and helps improve the performance stability of dynamically covalently cross-linked aromatic polyamide materials.

[0036] Specifically, the mass ratio of the long-chain dicarboxylic acid containing hydroxyl groups to the mass of the amino-terminated aromatic polyamide prepolymer is 10%, 20%, 30%, 40%, or any two of these, and the number average molecular weight of the amino-terminated aromatic polyamide prepolymer is 2000, 2500, 3000, 4000, 4500, 5000, or any two of these.

[0037] In some embodiments, the mass ratio of the hydroxyl-containing long-chain dicarboxylic acid to the mass of the amino-terminated aromatic polyamide prepolymer is 15% to 30%, for example, 15%, 20%, 25%, 30%, or any combination thereof, which helps to further improve the performance balance of the dynamically covalently crosslinked aromatic polyamide material.

[0038] In some embodiments, the preparation process of the above-mentioned long-chain dicarboxylic acid containing hydroxyl groups includes: oxidizing an unsaturated long-chain dicarboxylic acid in the presence of an alkali metal hydroxide and an oxidizing agent to obtain an oxidation product; and acidifying the oxidation product with a first inorganic acid to obtain the above-mentioned long-chain dicarboxylic acid containing hydroxyl groups. Using unsaturated long-chain dicarboxylic acids as raw materials, a directional oxidation reaction is carried out under the action of an alkali metal hydroxide and an oxidizing agent. This allows hydroxyl groups to be introduced into the carbon-carbon double bond positions of the unsaturated long-chain dicarboxylic acid, obtaining a structurally regular long-chain dicarboxylic acid with clearly defined hydroxyl sites. This facilitates the efficient formation of a dynamic ester bond crosslinking network between the dicarboxylic acid and amino-terminated prepolymers.

[0039] In some embodiments, the aforementioned unsaturated long-chain dicarboxylic acid is obtained from vegetable oil through hydrolysis and autodecomposition reactions; wherein, the aforementioned vegetable oil includes one or more of rubber seed oil, tallow tree oil, and high-oleic rapeseed oil. The vegetable oil raw material source is renewable, green and low-carbon, which helps to increase the bio-based carbon content of the final aromatic polyamide material, reduce dependence on petroleum-based raw materials, and meet the requirements of carbon neutrality and green manufacturing.

[0040] In some embodiments, the aforementioned unsaturated long-chain dicarboxylic acid includes octadecanoic acid-9-enedicarboxylic acid, whose long-chain structure and double bond sites are precise, providing a regular molecular framework for the subsequent directional oxidation to introduce hydroxyl groups, which helps to uniformly construct the dynamic covalent bond network of aromatic polyamide materials.

[0041] Specifically, the process for preparing octadecano-9-eneic acid from vegetable oil via hydrolysis and autodecomposition includes: adding 120g of vegetable oil, 36g of sodium hydroxide (NaOH), 60mL of water, and 360mL of ethanol sequentially to a round-bottom flask and refluxing at 90°C for 4 hours. After cooling, 72mL of hydrochloric acid is added. The organic phase is washed three times with 200mL of NaCl solution, then treated with anhydrous magnesium sulfate (MgSO4), evaporated, and dried in a vacuum oven at 40°C for 48 hours to obtain fatty acids. Subsequently, 100g of the above fatty acids is added to a 500mL round-bottom flask and stirred at 45°C for 1 hour under a nitrogen atmosphere. Then, a second-generation Grubb catalyst (2.13g, 0.5% mol, purity 99%, purchased from Aladdin) is added. The reaction mixture is sealed at 45°C. After approximately 4 hours, a precipitate forms in the reaction mixture. After 24 hours, the precipitate is purified by recrystallization multiple times in ethyl acetate to obtain octadecano-9-eneic acid.

[0042] In this embodiment, the vegetable oil can be any one of rubber seed oil, tallow tree oil, and high oleic rapeseed oil, or a mixed vegetable oil obtained by mixing two or more of them in any proportion. This invention does not impose any special restrictions on the grade of raw materials, mixing ratio, etc.

[0043] In some embodiments, the alkali metal hydroxides include one or more of potassium hydroxide and sodium hydroxide, which helps to promote the activation and oxidation of double bonds in unsaturated long-chain dicarboxylic acids, thereby improving the reaction conversion rate and raw material utilization rate.

[0044] In some embodiments, the oxidant includes potassium permanganate, which can oxidize the double bonds of unsaturated long-chain dicarboxylic acids, introduce hydroxyl groups at the double bond positions, and obtain hydroxyl-containing long-chain dicarboxylic acids with regular structures and single hydroxyl sites, which helps to improve their reactivity and crosslinking efficiency with double-terminated amino-capped prepolymers.

[0045] In some embodiments, the temperature of the oxidation reaction is 0°C to 10°C, for example, 0°C, 2°C, 5°C, 8°C, 10°C or any combination thereof, preferably 5°C, and the time is 10 min to 30 min, for example, 10 min, 15 min, 20 min, 25 min, 30 min or any combination thereof, preferably 20 min. This range helps the oxidation reaction to be under optimal kinetic conditions, which helps the double bond to be converted into a hydroxyl group and further improves the yield.

[0046] In some embodiments, the first inorganic acid includes concentrated hydrochloric acid, which has strong acidification ability and complete reaction, and can convert the oxidation product into the target hydroxyl-containing long-chain dicarboxylic acid, while removing metal ions and inorganic salt impurities in the system, improving purity and avoiding impurity residue.

[0047] In some embodiments, the above-mentioned amino-terminated aromatic polyamide prepolymer is polymerized from raw materials including diamines and diacids via a polycondensation reaction. The diacids include aromatic diacids, and the diamines include aromatic diamines. Both aromatic diacids and aromatic diamines are aromatic monomers with a rigid aromatic ring structure, which can improve the regularity of the prepolymer molecular chain, ensure the stability of the activity of the terminal amino groups of the prepolymer, and make the polycondensation and crosslinking reaction with hydroxyl-containing long-chain diacids more uniform and complete, further contributing to the performance stability of the dynamically covalently crosslinked aromatic polyamide material.

[0048] Specifically, the raw materials for the above-mentioned amino-terminated aromatic polyamide prepolymer also include a first catalyst, a second antioxidant, and water.

[0049] Specifically, the polymerization process of the above-mentioned amino-terminated aromatic polyamide prepolymer includes: placing a diamine, a diacid, a first catalyst, a second catalyst, and water in a reactor, purging nitrogen through a three-way valve, heating to 80°C~100°C and maintaining the temperature for 1 hour to complete the salt formation reaction; then continuing to heat to 220°C~240°C, maintaining a pressure of 1.5MPa~2MPa; then slowly depressurizing to atmospheric pressure, and then raising the temperature to 250~270°C, performing a vacuum polycondensation reaction for 20min~40min to obtain the amino-terminated aromatic polyamide prepolymer.

[0050] Specifically, the first catalyst includes one or more of hypophosphite, phosphorous acid, and sodium hypophosphite, and the amount of catalyst added is 0.01% to 0.3% of the sum of the mass of the dicarboxylic acid and the diamine.

[0051] Specifically, the second antioxidant includes one or more of the following: tris[2,4-di-tert-butylphenyl]phosphite (168), N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexanediamine (1098), pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (1010), octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (1076), and 3,5-di-tert-butyl-4-hydroxybenzyl diethylphosphonate (1222). The amount of the second antioxidant added is 0.01% to 0.3% of the sum of the mass of the diacid and the diamine.

[0052] In some embodiments, in the above-described polycondensation reaction, the total number of functional groups N of the carboxyl groups in the dicarboxylic acid is... COOH The total number of functional groups N of the amino groups in the above-mentioned diamines NH2The equivalence ratio r ranges from 0.8 to 0.93, for example, 0.8, 0.83, 0.86, 0.89, 0.92, 0.93, or any combination thereof. This range ensures that the terminal amino groups of the above-mentioned amino-terminated aromatic polyamide prepolymer have sufficient reaction sites with the carboxyl or ester groups of the hydroxyl-containing long-chain dicarboxylic acid. It avoids the occurrence of carboxyl-terminated prepolymers due to insufficient terminal amino groups, resulting in incomplete subsequent crosslinking reactions, incomplete dynamic networks, and limited improvement in material toughness. On the other hand, it avoids the loss of molecular weight control due to excessive terminal amino groups, further contributing to improving the performance stability of dynamically covalently crosslinked aromatic polyamide materials.

[0053] In the embodiments of this application, the number-average molecular weight of the amino-terminated aromatic polyamide prepolymer was calculated using the Carothers equation.

[0054] Specifically, the degree of polymerization in a polycondensation reaction is calculated using the following formula:

[0055]

[0056] in, The degree of polymerization is r, and the total number of carboxyl functional groups N in the above dicarboxylic acid is r. COOH The total number of functional groups N of the amino groups in the above-mentioned diamines NH2 The equivalence ratio, p is the degree of reaction between the diamine and the diacid monomer. The diamine monomer and the diacid monomer used in the embodiments of this application can both reach the molecular weight required for industrial application after polycondensation reaction, that is, the degree of reaction usually needs to reach 98.5%~99.5% or more. The p value in the embodiments of this application is 0.99.

[0057] The number-average molecular weight Mn is calculated as follows:

[0058]

[0059] Where M1 is the relative molecular mass of the diacid monomer, M2 is the relative molecular mass of the diamine monomer, and 36 is the relative molecular mass of one molecule of diamine that loses two molecules of water in the condensation reaction with one molecule of diacid.

[0060] In some embodiments, the aforementioned diamine includes one or more of the following: α,ω-linear aliphatic diamines with 4 to 14 carbon atoms, m-phenylenediamine, p-phenylenediamine, 1,4-cyclohexanedimethylamine, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 4,4'-diaminodicyclohexylmethane, and 4,4'-isopropyldicyclohexylamine. These encompass aliphatic diamines, aromatic diamines, and alicyclic diamines. The flexibility of the chain segment can be adjusted by aliphatic diamines, while the rigidity and heat resistance can be enhanced by aromatic / alicyclic diamines, allowing for flexible adaptation to different performance requirements and a high degree of freedom in raw material selection.

[0061] In some embodiments, the aforementioned dicarboxylic acid includes one or more of the following: α,ω-linear aliphatic dicarboxylic acids with 4 to 20 carbon atoms, isophthalic acid, terephthalic acid, 2,5-furandicarboxylic acid, phenylmalonic acid, terephthalic acid, biphenyl dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and 2,6-naphthalenedicarboxylic acid. These are all readily available industrial raw materials with sufficient supply and controllable costs. They are compatible with conventional salt-condensation polycondensation preparation processes, require no special equipment, and are easy to scale up for continuous production. At the same time, they help improve the batch stability of dynamically covalently cross-linked aromatic polyamide materials.

[0062] In some embodiments, the polymerization process includes: mixing the above-mentioned long-chain dicarboxylic acid containing hydroxyl groups with the raw material of the aromatic polyamide prepolymer with amino-terminated ends to obtain a mixture; subjecting the mixture to a polycondensation reaction and an ester exchange reaction to obtain the above-mentioned dynamically covalently crosslinked aromatic polyamide material.

[0063] The above-mentioned mixing treatment enables the hydroxyl-containing long-chain dicarboxylic acid and the amino-terminated aromatic polyamide prepolymer to be fully dispersed and uniformly contacted. The above-mentioned polycondensation reaction includes amidation polycondensation reaction and esterification polycondensation reaction. The amidation polycondensation reaction enables the terminal amino group of the prepolymer to condense with the carboxyl group of the long-chain dicarboxylic acid to form a stable amide bond, retaining the rigid main chain skeleton of the aromatic polyamide. The above-mentioned esterification polycondensation reaction enables the terminal carboxyl group and hydroxyl group of the hydroxyl-containing long-chain dicarboxylic acid to condense and form ester bond crosslinking points, providing sufficient reaction sites for subsequent transesterification reaction. The transesterification reaction can trigger the dynamic reversible exchange of hydroxyl groups and ester bonds in the reaction system. The above reactions contribute to the complete and uniform construction of the dynamic network of the aromatic polyamide material, giving the material the comprehensive advantages of high strength, high toughness, thermoforming and recyclability.

[0064] Specifically, the temperature of the above mixing process is 120℃~150℃, for example, 120℃, 130℃, 140℃, 150℃ or any combination thereof. This range allows the hydroxyl-containing long-chain dicarboxylic acid and the amino-terminated prepolymer to fully melt and disperse evenly, avoiding local agglomeration of raw materials, while suppressing premature polycondensation side reactions, laying the material foundation for subsequent uniform reaction.

[0065] Specifically, the temperature of the polycondensation reaction is 170℃~230℃, for example, 170℃, 180℃, 190℃, 200℃, 210℃, 220℃, 230℃ or any combination thereof. This range can match the activity threshold of amidation polycondensation and esterification polycondensation reactions in the polycondensation reaction, avoiding insufficient reaction due to excessively low temperature and side reactions due to excessively high temperature, which further helps to improve the performance stability of dynamically covalently cross-linked aromatic polyamide materials.

[0066] Specifically, the temperature of the above-mentioned transesterification reaction is 200℃~230℃, for example, 200℃, 210℃, 220℃, 230℃ or any combination thereof. This range allows the polycondensation and transesterification reactions to occur in parallel, allowing the unreacted amino, carboxyl, and hydroxyl groups in the system to continue the polycondensation reaction, increasing the degree of reaction. At the same time, the ester bonds already formed in the system undergo reversible dynamic exchange with the hydroxyl groups, forming a dynamically covalently cross-linked aromatic polyamide material.

[0067] More specifically, the above polymerization reaction can be carried out in a twin-screw extruder with a rotational speed of 60 rpm / min to 80 rpm / min, for example, 60 rpm / min, 70 rpm / min, 80 rpm / min or any combination thereof.

[0068] More specifically, the temperature of the above polymerization reaction can be controlled by different temperature control zones of the twin-screw extruder. For example, the first and second temperature control zones can be set to 120°C to 150°C for mixing, the third and fourth temperature control zones can be set to 170°C to 200°C for polycondensation, and the fifth and sixth temperature control zones can be set to 200°C to 230°C for polycondensation and transesterification.

[0069] More specifically, the raw materials of the above-mentioned long-chain dicarboxylic acid containing hydroxyl groups and the aromatic polyamide prepolymer with double-terminated amino groups also include a second catalyst. The second catalyst includes one or more of isopropyl titanate, tetrabutyl titanate, antimony trioxide, antimony glycolate, and stannous octoate. The amount of the second catalyst added is 0.05% to 0.1% of the sum of the mass of the long-chain dicarboxylic acid containing hydroxyl groups and the aromatic polyamide prepolymer with double-terminated amino groups.

[0070] In some embodiments, the raw materials of the above-mentioned long-chain dicarboxylic acid containing hydroxyl groups and the aromatic polyamide prepolymer with dual-terminated amino groups further include a first antioxidant, wherein the first antioxidant includes tris[2,4-di-tert-butylphenyl]phosphite (168), N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexanediamine (1098), pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (1010), β-(3, One or more of 5-di-tert-butyl-4-hydroxyphenyl)propionate (1076) and 3,5-di-tert-butyl-4-hydroxybenzyl diethylphosphonate (1222) can effectively capture free radicals generated in high-temperature reaction systems, decompose hydrogen peroxides, prevent thermal oxidation and breakage of aromatic polyamide segments and dynamic covalent bonds, avoid problems such as molecular weight reduction, mechanical property deterioration, and yellowing, and contribute to the performance stability of dynamically covalently cross-linked aromatic polyamide materials.

[0071] The present invention also provides an aromatic polyamide material prepared by the above-mentioned method, which has the properties of high rigidity and high toughness, and supports thermoforming and recycling.

[0072] In specific implementation, (1) the unsaturated long-chain dicarboxylic acid prepared by cracking vegetable oil is oxidized in the presence of alkali metal hydroxide and oxidant to obtain an oxidation product; the oxidation product is acidified with a first inorganic acid to obtain the long-chain dicarboxylic acid containing hydroxyl groups; (2) raw materials including diamine, dicarboxylic acid, first catalyst, second antioxidant and water are added to a reaction vessel for polymerization to obtain an aromatic polyamide prepolymer with double-terminated amino groups; (3) the long-chain dicarboxylic acid containing hydroxyl groups, the aromatic polyamide prepolymer with double-terminated amino groups, the first antioxidant and the second catalyst are mixed to obtain a mixture; the mixture is subjected to polycondensation reaction and transesterification reaction to obtain the above-mentioned dynamically covalently crosslinked aromatic polyamide material.

[0073] The present invention will be further described below through specific embodiments.

[0074] Example 1

[0075] S1. Preparation of long-chain dicarboxylic acids containing hydroxyl groups

[0076] 120 g of vegetable oil, 36 g of sodium hydroxide (NaOH), 60 mL of water, and 360 mL of ethanol were sequentially added to a round-bottom flask and refluxed at 90 °C for 4 h. After cooling, 72 mL of hydrochloric acid was added. The organic phase was washed three times with 200 mL of NaCl solution, then treated with anhydrous magnesium sulfate (MgSO4), evaporated, and dried in a vacuum oven at 40 °C for 48 h to obtain fatty acids. Subsequently, 100 g of the above fatty acids were added to a 500 mL round-bottom flask and stirred at 45 °C for 1 h under a nitrogen atmosphere. Then, 2.13 g of second-generation Grubb catalyst (0.5% mol, purity 99%, purchased from Aladdin) was added. The reaction mixture was sealed at 45 °C. After about 4 h, a precipitate formed in the reaction mixture. After 24 h, the precipitate was purified by recrystallization multiple times in ethyl acetate to obtain octadecano-9-enediic acid.

[0077] Octadecto-9-eneic acid (5.0 g) was added to an aqueous solution of KOH (2.5 g dissolved in 500 mL of water). The resulting mixture was heated to 50 °C and stirred until a clear solution was formed. The mixture was then cooled to 5 °C and diluted to 2000 mL. 500 mL of potassium permanganate solution (5.0 g, 31.64 mmol) was then added with stirring for 20 min. The reaction was stopped, and the solution was decolorized by adding saturated sodium bisulfite solution, followed by acidification with concentrated hydrochloric acid. The solution became colorless, and a white precipitate formed. Filtration yielded a long-chain dicarboxylic acid containing hydroxyl groups.

[0078] S2. Synthesis of amino-terminated aromatic polyamide prepolymers

[0079] 10 mol of m-phenylenediamine, 8.6 mol of adipic acid, 10 mol of deionized water, 0.1% of the total mass of phosphorous acid catalyst (added at 0.1% of the total mass of m-phenylenediamine and adipic acid), 0.05% of the total mass of m-phenylenediamine and adipic acid antioxidant 1098, and 0.1% of the total mass of m-phenylenediamine and adipic acid antioxidant 168 were sequentially added to a high-pressure reactor equipped with a stirrer. (Functional group N) COOH With functional group N NH2 The equivalence ratio r is 0.86. After sealing the reactor, the mixture is purged with nitrogen three times. The temperature is raised to 80°C and held for 1 hour to complete the salt formation reaction. After salt formation, the temperature is raised to 220°C and maintained at 1.5 MPa. Then the pressure is slowly released to atmospheric pressure, the material temperature is raised to 260°C, and the condensation reaction is carried out under vacuum for 30 minutes to complete the condensation reaction, yielding an aromatic polyamide prepolymer with a number average molecular weight of approximately 3000 g / mol and end-amino groups.

[0080] S3, Preparation of polyamide materials

[0081] The above-mentioned amino-terminated aromatic polyamide prepolymer, a hydroxyl-containing long-chain dicarboxylic acid (added at 20% of the mass of the polyamide prepolymer), tetrabutyl titanate catalyst (added at 0.05% of the total mass of the prepolymer and the hydroxyl-containing long-chain dicarboxylic acid), and antioxidant 1098 (added at 0.05% of the total mass of the prepolymer and the hydroxyl-containing long-chain dicarboxylic acid) were added to the main feed port of a twin-screw extruder for polymerization. The screw speed was set to 60 rpm / min, the temperature of the first and second temperature control zones of the extruder was set to 150°C for mixing, the temperature of the third and fourth temperature control zones was set to 200°C for polycondensation, and the temperature of the fifth and sixth temperature control zones was set to 230°C for polycondensation and transesterification. After completing the above reaction stages, the aromatic polyamide material sample was obtained by extrusion through the end of the extruder.

[0082] Example 2

[0083] S1. Preparation of long-chain dicarboxylic acids containing hydroxyl groups

[0084] Same as Example 1.

[0085] S2. Synthesis of amino-terminated aromatic polyamide prepolymers

[0086] Decanediamine (10 mol), terephthalic acid (8.3 mol), deionized water (10 mol), phosphorous hypophosphite catalyst (0.1% of the total mass of decanediamine and terephthalic acid), antioxidant 1098 (0.05% of the total mass of decanediamine and terephthalic acid), and antioxidant 168 (0.1% of the total mass of decanediamine and terephthalic acid) were sequentially added to a high-pressure reactor equipped with a stirrer. (Functional group N) COOH With functional group N NH2 The equivalence ratio r is 0.83. After sealing the reactor, the mixture is purged with nitrogen three times. The temperature is raised to 80°C and held for 1 hour to complete the salt formation reaction. After salt formation, the temperature is raised to 220°C and maintained at 1.5 MPa. Then the pressure is slowly released to atmospheric pressure, the material temperature is raised to 260°C, and a vacuum polycondensation reaction is carried out for 30 minutes to complete the polycondensation reaction, yielding an aromatic polyamide prepolymer with a number average molecular weight of approximately 3000 g / mol and end-amino groups.

[0087] S3, Preparation of polyamide materials

[0088] The above-mentioned amino-terminated aromatic polyamide prepolymer, a hydroxyl-containing long-chain dicarboxylic acid (added at 20% of the mass of the polyamide prepolymer), tetrabutyl titanate catalyst (added at 0.05% of the total mass of the prepolymer and the hydroxyl-containing long-chain dicarboxylic acid), and antioxidant 1098 (added at 0.05% of the total mass of the prepolymer and the hydroxyl-containing long-chain dicarboxylic acid) were added to the main feed port of a twin-screw extruder for polymerization. The screw speed was set to 60 rpm / min, the temperature of the first and second temperature control zones of the extruder was set to 150°C for mixing, the temperature of the third and fourth temperature control zones was set to 200°C for polycondensation, and the temperature of the fifth and sixth temperature control zones was set to 230°C for polycondensation and transesterification. After completing the above reaction stages, the aromatic polyamide material sample was obtained by extrusion through the end of the extruder.

[0089] Example 3: The difference from Example 1 is that the 10 mol of m-phenylenediamine added in step S2 is replaced with 5 mol of m-phenylenediamine and 5 mol of p-phenylenediamine. The remaining conditions of Example 3 are the same as those of Example 1.

[0090] Example 4: The difference from Example 1 is that the amount of long-chain dicarboxylic acid containing hydroxyl groups added in step S3 is changed from 20% to 40% of the mass of the aromatic polyamide prepolymer with amino-terminated ends; the temperature of the first and second temperature control zones of the extruder is set to 120°C, the temperature of the third and fourth temperature control zones is set to 170°C, and the temperature of the fifth and sixth temperature control zones is set to 200°C. The remaining conditions of Example 4 are the same as those of Example 1.

[0091] Example 5: The difference from Example 1 is that the amount of long-chain dicarboxylic acid containing hydroxyl groups added in step S3 is changed from 20% of the mass of the amino-terminated aromatic polyamide prepolymer to 10%; the temperature of the first and second temperature control zones of the extruder is set to 135°C, the temperature of the third and fourth temperature control zones is set to 185°C, and the temperature of the fifth and sixth temperature control zones is set to 215°C. The remaining conditions of Example 5 are the same as those of Example 1.

[0092] Example 6: The difference from Example 1 is that in step S2, the amount of m-phenylenediamine added is 10 mol, and the amount of adipic acid added is 8.0 mol (functional group N). COOH With functional group N NH2 The equivalence ratio r was 0.8), and the polycondensation reaction yielded an aromatic polyamide prepolymer with a number average molecular weight of approximately 2000 g / mol and end-amino groups. The remaining conditions of Example 6 were the same as those of Example 1.

[0093] Example 7: The difference from Example 1 is that in step S2, the amount of m-phenylenediamine added is 10 mol, and the amount of adipic acid added is 9.2 mol (functional group N). COOH With functional group N NH2 The equivalence ratio r was 0.92), and the polycondensation reaction yielded an aromatic polyamide prepolymer with a number average molecular weight of approximately 5000 g / mol and end-amino groups. The remaining conditions in Example 7 were the same as in Example 1.

[0094] Comparative Example 1

[0095] MXD6 pure resin, purchased from Mitsubishi Gas Chemical Co., Ltd.

[0096] Comparative Example 2

[0097] PA10T pure resin was purchased from Kingfa Science & Technology Co., Ltd.

[0098] Comparative Example 3: The difference from Example 1 is that the long-chain dicarboxylic acid containing hydroxyl groups in step S3 was replaced with a linear aliphatic α,ω-octadecyl diacid monomer (98% purity, purchased from Aladdin). The remaining conditions of Comparative Example 3 were the same as those of Example 1.

[0099] Comparative Example 4: The difference from Example 1 is that the long-chain dicarboxylic acid containing hydroxyl groups in step S3 is replaced with 2,3-dihydroxysuccinic acid. The remaining conditions of Comparative Example 4 are the same as those of Example 1.

[0100] Comparative Example 5: The difference from Example 1 is that the amount of long-chain dicarboxylic acid containing hydroxyl groups added in step S3 is changed from 20% of the mass of the amino-terminated aromatic polyamide prepolymer to 5%. The remaining conditions of Comparative Example 5 are the same as those of Example 1.

[0101] Comparative Example 6: The difference from Example 1 is that the amount of long-chain dicarboxylic acid containing hydroxyl groups added in step S3 is changed from 20% to 50% of the mass of the amino-terminated aromatic polyamide prepolymer. The remaining conditions of Comparative Example 6 are the same as those of Example 1.

[0102] Comparative Example 7: The difference from Example 1 is that in step S2, the amount of m-phenylenediamine added is 10 mol, and the amount of adipic acid added is 6.1 mol (functional group N). NH2 With functional group N COOH The equivalence ratio r was 0.61), and the polycondensation reaction yielded an aromatic polyamide prepolymer with a number average molecular weight of approximately 1000 g / mol and end-amino groups. The remaining conditions for Comparative Example 7 were the same as those for Example 1.

[0103] Comparative Example 8: The difference from Example 1 is that in step S2, the amount of m-phenylenediamine added is 10 mol, and the amount of adipic acid added is 9.6 mol (functional group N). COOH With functional group N NH2 The equivalence ratio r was 0.96), and the polycondensation reaction yielded an aromatic polyamide prepolymer with a number average molecular weight of approximately 8000 g / mol and end-amino groups. The remaining conditions for Comparative Example 8 were the same as those for Example 1.

[0104] The aromatic polyamide materials prepared in the examples and comparative examples were tested according to the following methods:

[0105] (1) Mechanical properties

[0106] According to GB / T 1040.1-2025, the Young's modulus, yield strength and elongation at break of the samples prepared in Examples 1 to 9 and Comparative Examples 1 to 6 were tested respectively.

[0107] The gauge length of the spline is 50 mm, the width is 10 mm, the thickness is 4 mm, and the stretching rate is 5 mm / min.

[0108] (2) Impact performance

[0109] According to ISO 179, the test specimen is an 80mm × 10mm × 4mm notched specimen (Type A notch).

[0110] Table 1

[0111]

[0112] As can be seen from Table 1, compared with Comparative Examples 1 to 8, Examples 1 to 7 introduce long-chain dicarboxylic acids containing hydroxyl groups to construct a dynamic covalent crosslinking network with aromatic polyamide prepolymers with double-terminated amino groups. This allows the aromatic polyamide material to undergo topological rearrangement when heated, giving it the ability to be thermally reshaped. Furthermore, the thermally reshaped aromatic polyamide material still retains good rigidity and toughness.

[0113] Compared with Comparative Example 1 (MXD6 resin) and Comparative Example 2 (PA10T resin), Example 1 and Example 2 significantly improved the elongation at break and (notched) impact strength by introducing long-chain dicarboxylic acids containing hydroxyl groups between the molecular chains. This improved the toughness and impact resistance of the aromatic polyamide materials, while maintaining the Young's modulus and yield strength at approximately the same level as commercially available products.

[0114] Comparative Example 3 used a hydroxyl-free linear octadecyl diacid to replace the hydroxyl-containing long-chain dicarboxylic acid. This only allowed for ordinary amidation chain extension and could not form a dynamic ester bond crosslinking network. Test results showed that its notched impact strength was only 2.5 kJ / m², with extremely limited toughening effect. Furthermore, the Young's modulus decreased to 1.8 GPa, indicating a significant loss of rigidity, failing to achieve the rigidity-toughness balance effect of this invention.

[0115] Comparative Example 4 used short-chain 2,3-dihydroxysuccinic acid to replace the long-chain dicarboxylic acid containing hydroxyl groups. Although the hydroxyl group could participate in cross-linking, it lacked the flexible segments of long-chain carbon. The test results showed that the material was extremely brittle, with an elongation at break of only 3.1% and a notched impact strength of only 0.4 kJ / m², and could not play a toughening role.

[0116] Compared with Comparative Examples 5 and 6, Examples 1-7 controlled the addition of hydroxyl-containing long-chain dicarboxylic acids to be 10%~40%, which helped to synergistically improve the rigidity, toughness and thermoforming properties of aromatic polyamide materials.

[0117] Compared with Comparative Examples 7 and 8, the number average molecular weight of the aromatic polyamide prepolymers with dual-amino-terminated ends controlled in Examples 1-7 was 2000-5000, which helped to synergistically improve the rigidity, toughness and thermoforming properties of the aromatic polyamide materials.

[0118] As can be seen from Table 1, by changing the structure of the diamine monomer in the polyamide prepolymer chain segment (m-phenylenediamine was used in Example 1, and p-phenylenediamine, which has greater rigidity, was used to partially replace it in Example 3), dynamic crosslinked materials with both high strength and high toughness can be successfully prepared.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a dynamically covalently crosslinked aromatic polyamide material, characterized in that, Includes the following steps: The aromatic polyamide material is obtained by polymerizing a raw material comprising a long-chain dicarboxylic acid containing hydroxyl groups and an aromatic polyamide prepolymer with amino-terminated ends. The long-chain dicarboxylic acid containing hydroxyl groups is 9,10-dihydroxyoctadecanoic acid; The mass ratio of the long-chain dicarboxylic acid containing hydroxyl groups to the mass ratio of the amino-terminated aromatic polyamide prepolymer is 10% to 40%. The number average molecular weight of the amino-terminated aromatic polyamide prepolymer is 2000-5000.

2. The method for preparing a dynamically covalently crosslinked aromatic polyamide material according to claim 1, characterized in that, The mass ratio of the long-chain dicarboxylic acid containing hydroxyl groups to the mass ratio of the amino-terminated aromatic polyamide prepolymer is 15% to 30%.

3. The method for preparing a dynamically covalently crosslinked aromatic polyamide material according to claim 1, characterized in that, The preparation process of the long-chain dicarboxylic acid containing hydroxyl groups includes: Unsaturated long-chain dicarboxylic acids are oxidized in the presence of alkali metal hydroxides and oxidants to obtain oxidation products. The oxidation product is acidified with a first inorganic acid to obtain the long-chain dicarboxylic acid containing hydroxyl groups.

4. The method for preparing a dynamically covalently crosslinked aromatic polyamide material according to claim 3, characterized in that, The unsaturated long-chain dicarboxylic acid is obtained from vegetable oil through hydrolysis and autodecomposition reactions; wherein, the vegetable oil includes one or more of rubber seed oil, tallow tree oil, and high-oleic rapeseed oil; And / or, the unsaturated long-chain dicarboxylic acid includes octadecano-9-enediol; And / or, the alkali metal hydroxide includes one or more of potassium hydroxide and sodium hydroxide; And / or, the oxidant includes potassium permanganate; And / or, the oxidation reaction is carried out at a temperature of 0°C to 10°C for a time of 10 min to 30 min; And / or, the first inorganic acid includes concentrated hydrochloric acid.

5. The method for preparing a dynamically covalently crosslinked aromatic polyamide material according to claim 1, characterized in that, The amino-terminated aromatic polyamide prepolymer is polymerized from raw materials including diamines and diacids via a polycondensation reaction, wherein the diacids include aromatic diacids and the diamines include aromatic diamines.

6. The method for preparing a dynamically covalently crosslinked aromatic polyamide material according to claim 5, characterized in that, In the polycondensation reaction, the total number of functional groups N of the carboxyl groups in the dicarboxylic acid is... COOH The total number of functional groups N of the amino groups in the diamine NH2 The equivalence ratio r ranges from 0.8 to 0.

93.

7. The method for preparing the dynamically covalently crosslinked aromatic polyamide material according to claim 6, characterized in that, The diamine includes one or more of the following: α,ω-linear aliphatic diamines with 4 to 14 carbon atoms: m-phenylenediamine, p-phenylenediamine, 1,4-cyclohexanedimethylamine, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 4,4'-diaminodicyclohexylmethane, and 4,4'-isopropyldicyclohexylamine; And / or, the dicarboxylic acid includes one or more of the following: α,ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms, isophthalic acid, terephthalic acid, 2,5-furandicarboxylic acid, phenylmalonic acid, terephthalic acid, biphenyl dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and 2,6-naphthalenedicarboxylic acid.

8. The method for preparing a dynamically covalently crosslinked aromatic polyamide material according to claim 1, characterized in that, The polymerization process includes: mixing the hydroxyl-containing long-chain dicarboxylic acid with a bi-amino-terminated aromatic polyamide prepolymer to obtain a mixture; subjecting the mixture to a polycondensation reaction and an transesterification reaction to obtain the aromatic polyamide material; wherein... The polycondensation reaction includes amidation polycondensation and esterification polycondensation; The temperature of the polycondensation reaction is 170℃~230℃; The transesterification reaction is carried out at a temperature of 200℃~230℃.

9. The method for preparing the dynamically covalently crosslinked aromatic polyamide material according to claim 1 or 8, characterized in that, The raw materials also include a first antioxidant, which includes one or more of the following: tris[2,4-di-tert-butylphenyl]phosphite, N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and 3,5-di-tert-butyl-4-hydroxybenzyl diethylphosphonate.

10. A dynamically covalently crosslinked aromatic polyamide material, characterized in that, It is prepared according to the preparation method of the aromatic polyamide material according to any one of claims 1 to 9.

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