Process for the preparation of polyetherketoneketones and use thereof

Abstract

The application discloses a polyether ketone ketone preparation method, a polyether ketone ketone and an application. The method comprises the following steps: (1) mixing raw materials at a first temperature, wherein the raw materials comprise acyl chloride, a solvent, a Lewis base, diphenyl ether and a Lewis acid, and after heat preservation, the temperature is increased to a second temperature to perform a first reaction stage; (2) increasing the temperature to a third temperature to perform a second reaction stage; and (3) adding a terminating agent to the reaction mixture of step (2). The temperature increasing rate in the step (1) and the step (2) is independently 0.1-5 ℃ / min. The weight average molecular weight of the polyether ketone ketone prepared by the method is between 5000-200000, and the molecular weight distribution coefficient is between 2.5-4.5. The polyether ketone ketone with a narrow molecular weight distribution is obtained through an electrophilic substitution path.

Description

Technical Field

[0001] This application relates to the field of polymers, specifically to the preparation method and uses of polyetherketoneketone. Background Technology

[0002] Polyetherketoneketone (PEKK), a high-performance specialty engineering plastic, is widely used in aerospace, automotive manufacturing, and electronics industries due to its high-temperature resistance, good self-lubrication, chemical resistance, radiation resistance, and excellent mechanical properties. In particular, PEKK with a narrow molecular weight distribution exhibits more stable mechanical properties, with significantly reduced fluctuations in tensile strength and impact toughness, effectively avoiding localized weaknesses caused by excessive molecular weight differences. In terms of thermal properties, its glass transition temperature (Tg) and melting temperature (Tm) are more concentrated, improving the material's stability and aging resistance at high temperatures. Furthermore, the melt viscosity of PEKK with a narrow molecular weight distribution is easier to control, improving processing performance. It exhibits more uniform flow during injection molding and extrusion processes, significantly reducing problems such as melt fracture, dimensional instability, and extrusion bulging caused by a wide molecular weight distribution, playing a crucial role in improving production efficiency and product yield. In terms of applications, high-end fields such as aerospace and medical devices (e.g., orthopedic implants) have extremely stringent requirements for the consistency and reliability of material properties. PEKK with a narrow molecular weight distribution can fully meet these requirements, ensuring the stable operation of key components in extreme environments and providing strong support for the safe operation of high-end equipment. Furthermore, the narrow molecular weight of PEKK also provides a more uniform molecular structure basis for subsequent material modification and functional design (e.g., composites, surface modification), further broadening its potential application scope.

[0003] The preparation routes of PEKK include electrophilic substitution and nucleophilic substitution. Research on electrophilic substitution can be traced back to the 1960s—DuPont reported a method for preparing polyetherketoneketone (PEKK) in nitrobenzene solution using aluminum trichloride as a catalyst and diphenyl ether and terephthaloyl chloride as monomers. However, this method has many side reactions, resulting in low intrinsic viscosity of the synthesized PEKK, making it impractical. Subsequently, research on the polymerization reaction of PEKK gradually developed into two routes: one is the Lewis acid-Lewis base co-catalysis method, which forms a PEKK gel in a chlorinated solvent / Lewis acid / Lewis base catalytic system. Although this method can produce high molecular weight polymers, it has many side reactions and poor batch stability, making it difficult to apply to industrial production; the other is a two-step route, which first prepares a trimer from diphenyl ether and terephthaloyl chloride and then refines it, then uses the refined trimer as a reactant to synthesize the PEKK product. However, this method has cumbersome reaction steps and high production costs.

[0004] Currently, the main method for preparing PEKK by electrophilic substitution is the Lewis acid-Lewis base co-catalysis method. Although this method can achieve polymerization at room temperature, the formation of a gel-like complex system during the reaction process leads to a significant decrease in the polymerization rate in the later stages, a prolonged reaction time, and the product tends to accumulate on the inner wall of the reactor, which seriously affects heat transfer and temperature control, ultimately resulting in a problem of excessively wide polymer molecular weight distribution.

[0005] Therefore, existing methods for preparing polyetherketones using electrophilic substitution routes, especially those for polyetherketones with narrow molecular weight distributions, still need improvement. Summary of the Invention

[0006] In view of the above problems, this application provides polyetherketoneketone and a method for preparing polyetherketoneketone, which can obtain polyetherketoneketone with a relatively narrow molecular weight distribution through electrophilic substitution: This application divides the synthesis reaction into different stages, controls the reaction temperature of each stage separately, increases the reaction temperature in a stepwise manner so that the reaction temperature is synchronized with the molecular chain extension, and adjusts the order of feeding raw materials to promote the forward reaction and reduce the probability of local reaction termination, thereby making the molecular weight of the product form a narrow distribution.

[0007] In one aspect of this application, a polyether ketone ketone (PEKK) is disclosed. The PEVKK has a weight-average molecular weight between 5000 and 200000, and a molecular weight distribution of 2.5-4.5. This PEVKK exhibits a narrow molecular weight distribution, high molecular weight, and good performance, and has broad application prospects in aerospace, electronics, instrumentation, medical, automotive manufacturing, and energy fields.

[0008] In another aspect, this application provides a method for preparing polyether ketone, comprising the following steps:

[0009] (1) The raw materials are mixed at a first temperature, the raw materials including acyl chloride, solvent, Lewis base, diphenyl ether and Lewis acid, and then heated to a second temperature to carry out the first reaction stage;

[0010] (2) The reaction product of step (1) is subjected to a second reaction stage at a third temperature;

[0011] (3) Add a terminator to the reaction mixture from step (2);

[0012] in:

[0013] The third temperature is greater than the second temperature, the second temperature is greater than the first temperature, the heating rate in step (1) and step (2) is independently 0.1~5℃ / min, and the weight average molecular weight of the polyether ketone prepared by the method is between 5000-200000, and the molecular weight distribution is 2.5-4.5.

[0014] According to an embodiment of the present invention, the order of feeding the raw materials is as follows: acyl chloride, solvent, Lewis base, diphenyl ether, and Lewis acid.

[0015] According to an embodiment of the present invention, the reaction process is carried out under conditions of inert gas purging.

[0016] According to an embodiment of the present invention, steps (1), (2) and (3) are performed under anhydrous conditions.

[0017] According to an embodiment of the present invention, the molar ratio of the solvent to the acyl chloride is 2:1 to 30:1.

[0018] According to an embodiment of the present invention, the molar ratio of the solvent to the acyl chloride is 2:1 to 15:1.

[0019] According to an embodiment of the present invention, the molar ratio M of the added Lewis acid to the sum of the added acyl chloride and Lewis base is... 路易斯酸 :(M 酰氯 +M 路易斯碱 The ratio is 1.1:1 to 3.0:1, preferably 1.2:1 to 1.8:1;

[0020] According to an embodiment of the present invention, the molar ratio of the acyl chloride to the Lewis base is 1:1 to 1:4, and optionally 1:1.5 to 1:3.5.

[0021] According to an embodiment of the present invention, the molar ratio of the diphenyl ether to the acyl chloride is 0.8:1 to 1.2:1, and optionally 0.95:1 to 1.05:1.

[0022] According to an embodiment of the present invention, the acyl chloride may be selected from one, two, or three of terephthaloyl chloride, phthaloyl chloride, and isophthaloyl chloride.

[0023] According to an embodiment of the present invention, the Lewis base may be selected from one, two or more of N,N-dimethylformamide, dimethylacetamide, diphenyl sulfone, triphenylphosphine oxide, nitropropane, sulfolane, dimethyl sulfoxide, dimethyl sulfone, N-methylpyrrolidone, anhydrous lithium chloride, and anhydrous sodium chloride.

[0024] According to an embodiment of the present invention, the Lewis acid may be selected from one, two or more of anhydrous aluminum trichloride, anhydrous ferric trichloride, boron trifluoride, anhydrous zinc dichloride, anhydrous antimony pentachloride, and anhydrous tin dichloride.

[0025] According to an embodiment of the present invention, the solvent may be selected from one, two or more of dichloromethane, dichloroethane, o-dichlorobenzene, carbon disulfide, and nitrobenzene.

[0026] According to an embodiment of the present invention, the order of feeding is acyl chloride, solvent, Lewis base, diphenyl ether, and finally Lewis acid.

[0027] According to an embodiment of the present invention, the heating rate in step (1) and step (2) is independently 0.1~2℃ / min.

[0028] According to an embodiment of the present invention, the first temperature is -25℃ to -10℃.

[0029] According to an embodiment of the present invention, the second temperature is -5℃ to 5℃.

[0030] According to an embodiment of the present invention, the third temperature is 20°C to 35°C.

[0031] According to an embodiment of the present invention, step (1) further includes heating from the first temperature to the second temperature, and the heating rate can be 0.1~1℃ / min.

[0032] According to an embodiment of the present invention, step (2) further includes raising the temperature from the second temperature to the third temperature, and the heating rate can be 1~2℃ / min.

[0033] According to an embodiment of the present invention, the reaction time of the first reaction stage is 0.5-1.5 hours.

[0034] According to an embodiment of the present invention, the reaction time of the second reaction stage is 3-5 hours.

[0035] According to an embodiment of the present invention, the first reaction stage and the second reaction stage are carried out under stirring conditions.

[0036] For example, in step (1), when the acyl chloride, diphenyl ether, Lewis acid, Lewis base and solvent are mixed at the first temperature, the stirring rate is 200~350 rpm.

[0037] For example, in step (1), the stirring rate of the first reaction stage is 200-400 rpm.

[0038] For example, in step (2), the stirring rate of the second reaction stage is 100-400 rpm.

[0039] According to an embodiment of the present invention, in step (3), after the reaction in the second reaction stage is completed, stirring is stopped and a terminator is added.

[0040] According to an embodiment of the present invention, in step (3), the terminator is 0.1% to 10% hydrochloric acid. Preferably, after adding the terminator, the reaction product is allowed to stand, for example, for more than 1 hour, such as 4-10 hours.

[0041] According to an embodiment of the present invention, step (3) further includes: sequentially crushing, sieving and washing the reaction product.

[0042] Preferably, the crushing process includes grinding and pulverizing.

[0043] Preferably, the washing process includes water washing, organic solvent washing, and / or acid washing. For example, the organic solvent washing may use methanol; and / or, the acid used in the acid washing may be 0.1% to 5% dilute hydrochloric acid.

[0044] In another aspect of the invention, the use of polyetherketoneketone in the preparation of functional components is proposed. The polyetherketoneketone has a molecular weight distribution coefficient between 2.5 and 4.5, and the functional components include those used in aerospace systems, electrical and electronic systems, instrumentation, medical devices, automobiles, lithium-ion batteries, solar cells, and energy delivery systems. Attached Figure Description

[0045] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0046] Figure 1 The image shows the weight-average molecular weight distribution of the polymer obtained in Example 1 of this application;

[0047] Figure 2 The image shows the weight-average molecular weight distribution of the polymer obtained in Example 2 of this application;

[0048] Figure 3 The image shows the weight-average molecular weight distribution of the polymer obtained in Example 3 of this application;

[0049] Figure 4 The image shows the weight-average molecular weight distribution of the polymer obtained in Example 4 of this application;

[0050] Figure 5 The image shows the weight-average molecular weight distribution of the polymer obtained in Example 5 of this application;

[0051] Figure 6 The image shows the weight-average molecular weight distribution of the polymer obtained in Comparative Example 1 of this application.

[0052] Figure 7 The image shows the weight-average molecular weight distribution of the polymer obtained in Comparative Example 2 of this application;

[0053] Figure 8The diagram shows the weight-average molecular weight distribution of the polymer obtained in Comparative Example 3 of this application.

[0054] Figure 9 The diagram shows the weight-average molecular weight distribution of the polymer obtained in Comparative Example 4 of this application;

[0055] Figure 10 The image shows the weight-average molecular weight distribution of the polymer obtained in Comparative Example 5 of this application;

[0056] Figure 11 The infrared spectra of polymers prepared according to embodiments and comparative examples of this application are shown. Detailed Implementation

[0057] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0058] Unless otherwise defined, all 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 pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0059] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0060] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0061] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0062] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0063] Unless otherwise stated, the terms used in this application have their common meanings as commonly understood by those skilled in the art. Unless otherwise stated, the values ​​of the parameters mentioned in this application can be measured using various measurement methods commonly used in the art (e.g., they can be tested according to the methods given in the embodiments of this application).

[0064] In one aspect of this application, a polyether ketone ketone (PEKK) is disclosed. The PEVKK has a weight-average molecular weight between 5000 and 200000, and a molecular weight distribution of 2.5-4.5. The weight-average molecular weight of the PEVKK is optionally between 10000-180000 and 20000-150000, and the molecular weight distribution is optionally between 2.6-4.4, 2.7-4.3, 2.8-4.2, 2.9-4.1, and 3.0-4.0. This application obtains a PEVKK with a narrow molecular weight distribution through an electrophilic substitution pathway. This PEVKK has a narrow molecular weight distribution, a high molecular weight, and good performance, and has broad application prospects in aerospace, electronics, instrumentation, medical, automotive manufacturing, and energy fields.

[0065] This polyether ketone can be prepared using the following method:

[0066] In another aspect of this application, a method for preparing polyether ketone ketone is provided. The method includes: (1) mixing raw materials, including acyl chloride, solvent, Lewis base, diphenyl ether, and Lewis acid, at a first temperature, maintaining the temperature, and then raising the temperature to a second temperature for a first reaction stage; (2) raising the temperature of the reaction product from step (1) to a third temperature for a second reaction stage; and (3) adding a terminator to the reaction mixture from step (2). The third temperature is higher than the second temperature, and the second temperature is higher than the first temperature. The heating rates in steps (1) and (2) are independently 0.1~5℃ / min. This facilitates obtaining a narrowly distributed polyether ketone ketone, with the molecular weight distribution of the obtained polyether ketone ketone being between 2.5 and 4.5.

[0067] As mentioned earlier, the preparation of PEKK using the electrophilic substitution method typically involves the addition of Lewis acids and Lewis bases. The combined action of these two substances causes the resulting polymer to form a complex system in solution, as shown in the typical reaction equation below:

[0068]

[0069] Specifically, electrophilic substitution typically involves preparing PEKK using diphenyl ethers and acyl chloride compounds under the co-catalysis of Lewis acids and Lewis bases. This method, through the combined action of Lewis acids and Lewis bases, causes the resulting polymer to form a complex system in solution, thereby obtaining sufficient active end groups to allow for continuous chain growth. To obtain PEKK products with a narrow molecular weight distribution, it is necessary to control the homogeneity of the reaction system, reducing the probability of localized chain growth differences, or localized slowdowns or even termination of the reaction rate, thus obtaining a polymer product with a more concentrated molecular weight distribution. Therefore, relatively strict control of the reaction temperature and the homogeneity of the system is required. Furthermore, as mentioned earlier, although the aforementioned complex system can obtain sufficient active end groups for continuous chain growth, the complex system exists in a gel state, resulting in a slow polymerization rate in the later stages of the reaction, requiring a longer time to reach the desired degree of polymerization. The gel-state reaction system also hinders heat dissipation, increasing the difficulty of controlling the reaction temperature in the later stages of polymerization. Moreover, this reaction system also requires control of the synchronicity of the polycondensation reaction and chain growth to obtain a polymer product with a narrow molecular weight distribution. This application, based on the principle of preparing PEKK through electrophilic substitution, divides the synthesis reaction into different stages and separately controls the reaction temperature of each stage. In the initial stage of the reaction, a low-temperature start-up reaction is used to control the initial reaction rate and improve the uniformity of the system in the initial polycondensation stage. By gradually increasing the reaction temperature, the reaction temperature is synchronized with the molecular chain elongation, reducing the risk of increased chain length differences due to diffusion rate changes or changes in reaction activation energy caused by temperature fluctuations or excessively high initial reaction temperatures.

[0070] According to the embodiments of this application, a low-temperature start-up method is adopted, and the order of adding raw materials can be acyl chloride, solvent, Lewis base, diphenyl ether, and Lewis acid in sequence. This avoids the "false dilution" effect caused by uneven solvent distribution around the monomer in the early stages of the reaction due to the dropwise addition of monomer, reducing the probability of forming cyclic small molecules and thus narrowing the molecular weight distribution of the product.

[0071] Specifically, in this application, "low-temperature" start-up reaction refers to controlling the temperature of the reaction system at a low level before the reaction begins, that is, adding the reactants to the solvent at a first temperature and achieving uniform mixing. This can be -10°C or below, or even -20°C or below.

[0072] According to embodiments of this application, the first reaction stage is the initial stage of the polymerization reaction. During this stage, the monomers undergo condensation polymerization, removing small molecule products such as HCl to form dimers or trimers, or other polymers. If the initial reaction rate is too fast or uneven in this stage, oligomers with large differences in chain length will be rapidly generated, potentially leading to a wide molecular weight distribution. Therefore, optimizing reaction conditions to control the initial reaction rate, promote the formation of relatively uniform oligomers, and smoothly transition to the efficient chain growth stage is beneficial for obtaining PEKK with a narrow molecular weight distribution.

[0073] This application initiates the reaction at a low temperature and pre-mixes the reactants evenly, then raises the temperature to a second temperature for the first reaction stage. This allows for better control of the initial reaction rate and chain growth process, which is beneficial for obtaining PEKK with a narrow molecular weight distribution. Specifically, the low temperature at which the reactants are mixed, i.e., the first temperature, can be -25℃ to -10℃, for example, -25℃, -24℃, -23℃, -22℃, -21℃, -20℃, -19℃, -18℃, -17℃, -16℃, -15℃, -14℃, -13℃, -12℃, -11℃, etc. The heating rate from the initial first temperature to the second temperature can be 0.1-4.5℃ / min, 0.1-4℃ / min, 0.1-3.5℃ / min, 0.1-3℃ / min, 0.1-2.5℃ / min, 0.1-2℃ / min, for example, specifically 0.1℃ / min, 0.2℃ / min, 0.3℃ / min, 0.4℃ / min, 0.5℃ / min, 0.6℃ / min, 0.7℃ / min, 0.8℃ / min, 0.9℃ / min, 1.0℃ / min, 1.1℃ / min, 1.2℃ / min, 1.3℃ / min, 1.4℃ / min, 1.5℃ / min, 1.6℃ / min, 1.7℃ / min, 1.8℃ / min, 1.9℃ / min, 2℃ / min, thereby heating the reaction system to the second temperature.

[0074] In some embodiments, before adding reactants and catalysts, such as Lewis acids and Lewis bases, to the reaction system, the reaction vessel can be pre-temperature adjusted and filled with inert gas to maintain a low temperature. Inert gases such as nitrogen can replace the air in the reaction vessel to keep the reaction system dry. Subsequently, a certain proportion and amount of raw materials, namely acyl chlorides, Lewis bases, Lewis acids, diphenyl ethers, and solvents, can be introduced and stirred until homogeneous. Because the reaction system is at a low temperature at this time, the probability of monomer condensation is low before the reactants are homogeneously mixed, allowing the reactants to begin condensation in a more uniformly distributed environment. This helps to eliminate pseudo-dilution and narrow the molecular weight distribution of the products. The stirring rate can be 200-350 rpm, which facilitates rapid and homogeneous mixing of the substances added to the reaction vessel.

[0075] According to the embodiments of this application, the order of adding raw materials is as follows: acyl chloride, solvent, Lewis base, diphenyl ether, and Lewis acid. This provides a more uniform reaction environment, reducing localized reactant concentration variations caused by reagent addition after the reaction begins. Furthermore, it introduces a stabilizing intermediate in the early stages of the reaction, adjusting the monomer reactivity. The Lewis base is added to the reaction system before the diphenyl ether. The weak basicity of the Lewis base also facilitates the removal of acidic substances such as HCl, thereby promoting the forward reaction and yielding PEKK with a higher molecular weight. Finally, the Lewis acid is added in excess to ensure that the acyl chloride is fully activated to generate an active acyl cation. The Lewis base can fully coordinate and play a co-catalytic role, while simultaneously offsetting the consumption of the Lewis acid by impurities in the system, ensuring a highly efficient and complete reaction.

[0076] According to embodiments of this application, the specific types of acyl chlorides, Lewis acids, Lewis bases, and solvents can be selected according to actual needs. For example, the acyl chloride may include at least one of terephthaloyl chloride, phthaloyl chloride, and isophthaloyl chloride; the Lewis base may include at least one of N,N-dimethylformamide, dimethylacetamide, diphenyl sulfone, triphenylphosphine oxide, nitropropane, sulfolane, dimethyl sulfoxide, dimethyl sulfone, N-methylpyrrolidone, anhydrous lithium chloride, and anhydrous sodium chloride, preferably N,N-dimethylformamide. The Lewis acid may include at least one of anhydrous aluminum trichloride, anhydrous ferric chloride, boron trifluoride, anhydrous zinc dichloride, anhydrous antimony pentachloride, and anhydrous tin dichloride, preferably anhydrous aluminum trichloride. The solvent may include any one or more of dichloromethane, dichloroethane, o-dichlorobenzene, carbon disulfide, and nitrobenzene, preferably dichloroethane.

[0077] According to embodiments of this application, adjusting the ratio of monomer, Lewis acid and Lewis base, and solvent can also help narrow the molecular weight distribution of the product and improve the quality of the obtained PEKK. For example, the molar ratio of solvent to acyl chloride is 2:1 to 30:1, optionally 2:1 to 15:1, such as 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, or 14:1. When the proportion of monomer in the reaction system is appropriate, the probability of excessive monomer acting as a capping agent leading to molecular chain termination can be reduced, thereby increasing the molecular weight of the obtained product and maintaining a narrower molecular weight distribution. Furthermore, an appropriate solvent content also helps maintain a moderate viscosity of the reaction system, reducing the occurrence of mass transfer barriers caused by increased viscosity, or situations where excessive solvent dilutes the monomer concentration, leading to a decrease in the reaction rate, which is unfavorable for the formation of a narrow-distribution polymer. The molar ratio of the Lewis base to the acyl chloride is 1.5:1 to 3.5:1, optionally 2:1 to 3.0:1, for example, 1.5:1, 1.8:1, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3.0:1, 3.2:1, 3.5:1, etc. This ratio ensures sufficient complexation of the active intermediate, stabilizes the reaction system, and prevents a sudden increase in system viscosity. If the ratio is too low, it will lead to premature product precipitation and a broadened molecular weight distribution; if it is too high, it will consume too much catalyst, weakening the system's ability to activate the acyl chloride. The molar ratio M of the added Lewis acid to the sum of the added molar amounts of the acyl chloride and the Lewis base is... 路易斯酸 :(M 酰氯 +M 路易斯碱The ratio is 1.1:1 to 3.0:1, optionally 1.2:1 to 1.8:1, for example, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 2.0:1, 2.5:1, 3.0:1, etc. This ratio is designed to provide a sufficient but not excessive amount of catalytic active centers. Too low a ratio results in insufficient catalytic efficiency, slow reaction, and low product molecular weight; too high a ratio easily leads to excessively vigorous local reactions, increased side reactions, and a wider molecular weight distribution. The molar ratio of diphenyl ether to acyl chloride is 0.8:1 to 1.2:1, optionally 0.95:1 to 1.05:1, for example, 0.8:1, 0.9:1, 0.95:1, 0.98:1, 1.0:1, 1.03:1, 1.05:1, 1.08:1, 1.1:1, 1.15:1, 1.2:1. This ratio is beneficial for forming high molecular weight polymers. When any monomer is in excess, the excess monomer will act as a chain terminator, prematurely stopping chain growth, resulting in a decrease in molecular weight and a broadening of the molecular weight distribution. Therefore, it is beneficial to further optimize the ratio of reactants, improving reactivity while maintaining the homogeneity of the reaction in the system. More specifically, the molar ratio of the acyl chloride to the Lewis base is 1:1 to 1:4; the molar ratio of the amount of Lewis acid added to the sum of the molar amounts of the acyl chloride and the Lewis base added is, in other words, the molar ratio M of the amount of Lewis acid added to the sum of the molar amounts of the acyl chloride and the Lewis base added. 路易斯酸 :(M 酰氯 +M 路易斯碱 The ratio is 1.1:1 to 3.0:1, preferably 1.2:1 to 1.8:1, for example, it can be 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2.0:1, 2.2:1, 2.5:1, or 3.0:1.

[0078] According to embodiments of this application, the second temperature can be -5℃ to 5℃, preferably -4℃, -3℃, -2℃, -1℃, 0℃, 1℃, 2℃, 3℃, or 4℃. This temperature is still relatively low, which is beneficial for controlling the polycondensation reaction rate at this stage, promoting the formation of oligomers with a relatively uniform degree of polymerization, and reducing the risk of increased differences in oligomer chain length due to excessively rapid reaction, thereby obtaining PEKK with a narrow molecular weight distribution. The reaction time of the first reaction stage at the second temperature can be shorter, such as 0.5-1.5 hours. The stirring rate of the first reaction stage can be slightly increased, for example, the stirring rate can be 300-400 rpm. This reduces the chain growth rate at this stage, forming polymers with a moderate degree of polymerization. Finally, a suitable amount of polymer can be polymerized to serve as a uniform basic unit for subsequent further polycondensation, thereby controlling the molecular weight distribution of the final product within a narrow range.

[0079] According to the embodiments of this application, the reaction temperature can be further increased to increase the molecular weight and obtain polyetherketoneketone. Specifically, the temperature can be raised to a third temperature and a second-stage reaction can be carried out. Specifically, the third temperature can be 20-35°C, for example, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C, or 35°C. The stirring rate at this time can be 100-400 rpm. The heating rate from the second temperature to the third temperature can be 0.1-4.5℃ / min, 0.1-4℃ / min, 0.1-3.5℃ / min, 0.1-3℃ / min, 0.1-2.5℃ / min, or 0.1-2℃ / min, specifically 0.1℃ / min, 0.2℃ / min, 0.3℃ / min, 0.4℃ / min, 0.5℃ / min, 0.6℃ / min, 0.7℃ / min, 0.8℃ / min, 0.9℃ / min, 1.0℃ / min, 1.1℃ / min, 1.2℃ / min, 1.3℃ / min, 1.4℃ / min, 1.5℃ / min, 1.6℃ / min, 1.7℃ / min, 1.8℃ / min, 1.9℃ / min, or 2℃ / min. This is beneficial for further narrowing the molecular weight distribution of the product.

[0080] According to embodiments of this application, the reaction time of the second reaction stage can be longer than that of the first reaction stage, specifically 3-5 hours, for example, 4 hours. This allows for sufficient chain elongation, increasing the molecular weight of the obtained PEKK. Insufficient reaction time leads to incomplete polymerization and a lower molecular weight, while excessive reaction time results in thermal degradation or side reactions that reduce the molecular weight and broaden the molecular weight distribution. Therefore, an appropriate reaction time is beneficial for obtaining PEKK with a narrow molecular weight distribution.

[0081] According to embodiments of this application, an inert gas, such as nitrogen, argon, or neon, is continuously introduced into the reaction space during the mixing of reactants and the first and second reaction stages. During the reaction stages, the byproduct HCl is removed by timely purging with the inert gas, promoting the forward reaction and reducing the probability of local reaction termination, thereby resulting in a narrow molecular weight distribution of the products. This approach maintains the reaction under an inert atmosphere, reducing the influence of moisture in the air on the reaction. Furthermore, the inert gas can be used to purge and remove the HCl product from the reaction system under stirring. This further facilitates a reduction in the molecular weight distribution.

[0082] According to the embodiments of this application, after the second reaction stage is completed, a terminator such as dilute hydrochloric acid can be added to achieve decomplexation, thereby terminating the reaction step and fixing the chain length in a timely manner. This allows for the preparation of high molecular weight, high purity, and narrow molecular weight distribution PEKK. Specifically, after the second reaction stage is completed, stirring can be stopped, dilute hydrochloric acid can be added, and the mixture can be allowed to stand for 4-10 hours. This further narrows the molecular weight distribution of the product.

[0083] According to embodiments of this application, after the second reaction stage, the obtained product can be sequentially subjected to crushing, sieving, and washing treatments. The crushing treatment includes grinding and pulverizing, and the washing treatment includes water washing, methanol washing, and acid washing. This further improves the quality of the product.

[0084] In another aspect of this application, the use of polyetherketoneketone in the preparation of functional components having a molecular weight distribution coefficient between 2.5 and 4.5 is proposed. The functional components include those used in aerospace systems, electronic and electrical systems, instruments and equipment, medical devices, automobiles, lithium-ion batteries, solar cells, and energy transmission systems.

[0085] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0086] Example 1

[0087] Install a thermometer, stirrer, and gas delivery tube on a four-necked flask. Place the apparatus in a cryogenic bath and set the temperature to -20°C. Connect the nitrogen flow meter to the nitrogen pipeline, turn on the nitrogen gas, and continuously introduce nitrogen through the gas delivery tube to purge air from the reaction flask for at least 30 minutes to remove air from the reaction flask and keep the reaction system dry. Turn on the stirrer; weigh 27.6 g isophthaloyl chloride, 64 g terephthaloyl chloride, 183.2 g dichloroethane, and 75 g Lewis base N,N-dimethylformamide and add them sequentially to the four-necked flask; weigh 76.8 g diphenyl ether and add it dropwise to the flask, then stir for 0.5 hours at a stirring rate of 250 rpm; weigh 315 g Lewis base N,N-dimethylformamide... Anhydrous aluminum trichloride was added to a four-necked flask and kept at the temperature for 1 hour. Then, the temperature was increased to 0°C at a rate of 1°C / min and stirred at 300 rpm. After reacting for 1 hour, the temperature was increased to 30°C at a rate of 1°C / min and maintained at the temperature, while stirring at 350 rpm. After reacting for 4 hours, stirring was stopped, and dilute hydrochloric acid was added to decomposite the polymer. After standing for 10 hours, a colloidal polymer was obtained. The polymer was then ground, pulverized, and sieved. After washing with deionized water, methanol, and hydrochloric acid, respectively, crude PEKK was obtained.

[0088] The molecular weight distribution diagram of the crude PEKK obtained in Example 1 is shown in the figure. Figure 1 Where the horizontal axis represents the weight-average molecular weight M. W dw / dlogM is the weighted average differential distribution function, and %Ht is the normalized value of dw / dlogM.

[0089] Example 2

[0090] The remaining operations are the same as in Example 1, except that after starting the reaction at -20°C, the reaction system is heated to 0°C at a heating rate of 1°C / min and kept at that temperature for 1 hour, and then the reaction system is heated to 30°C at a heating rate of 2°C / min and reacted for 4 hours.

[0091] Example 3

[0092] The remaining operations are the same as in Example 1, except that after starting the reaction at -20°C, the reaction system is heated to 0°C at a heating rate of 2°C / min and kept at that temperature for 1 hour, and then the reaction system is heated to 30°C at a heating rate of 1°C / min and reacted for 4 hours.

[0093] Example 4

[0094] The remaining operations are the same as in Example 1, except that after starting the reaction at -20°C, the reaction system is heated to 0°C at a heating rate of 0.1°C / min and kept at that temperature for 1 hour, and then the reaction system is heated to 30°C at a heating rate of 1°C / min and reacted for 4 hours.

[0095] Example 5

[0096] The remaining operations are the same as in Example 1, except that after starting the reaction at -20°C, the reaction system is heated to 0°C at a heating rate of 1°C / min and kept at that temperature for 1 hour, and then the reaction system is heated to 30°C at a heating rate of 0.1°C / min and reacted for 4 hours.

[0097] Comparative Example 1

[0098] The materials were fed according to the material ratio in Example 1, and the reaction system was directly heated from -20°C to 30°C at a constant heating rate of 5°C / min, with all other conditions remaining the same.

[0099] Comparative Example 2

[0100] The feeding and heating procedures are the same as in Example 1, but the nitrogen supply is shut off throughout the process.

[0101] Comparative Example 3

[0102] Install a thermometer, stirrer, and gas delivery tube on a four-necked flask. Place the apparatus in a cryogenic bath and set the temperature to -20°C. Connect the nitrogen flow meter to the nitrogen pipeline, turn on the nitrogen gas, and continuously introduce nitrogen through the gas delivery tube for at least 30 minutes to remove air from the reaction flask and keep the reaction system dry. Turn on the stirrer; weigh 27.6 g of isophthaloyl chloride, 64 g of terephthaloyl chloride, and 183.2 g of dichloroethane and add them sequentially to the four-necked flask; weigh 76.8 g of diphenyl ether and add it dropwise to the flask, then stir for 0.5 hours at a stirring rate of 250 rpm; weigh 315 g of Lewis acid anhydrous aluminum trichloride and add it to the four-necked flask, then add 7... 5g of Lewis base N,N-dimethylformamide was heated to 0°C at a rate of 1°C / min and stirred at 300 rpm for 1 hour. After 1 hour of reaction, the system was heated to 30°C at a rate of 1°C / min and maintained at 350 rpm. After 4 hours of reaction, stirring was stopped, dilute hydrochloric acid was added to decomplex the polymer, and the mixture was allowed to stand for 10 hours to obtain a gel-like polymer. The polymer was then ground, pulverized, and sieved, and washed with deionized water, methanol, and hydrochloric acid to obtain crude PEKK.

[0103] Comparative Example 4

[0104] The remaining operations are the same as in Example 1, except that after starting the reaction at -20°C, the reaction system is heated to 0°C at a heating rate of 1°C / min and kept at that temperature for 1 hour, and then the reaction system is heated to 30°C at a heating rate of 10°C / min and reacted for 4 hours.

[0105] Comparative Example 5

[0106] The remaining operations are the same as in Example 1, except that after starting the reaction at -20°C, the reaction system is heated to 0°C at a heating rate of 10°C / min and kept at that temperature for 1 hour, and then the reaction system is heated to 30°C at a heating rate of 1°C / min and reacted for 4 hours.

[0107] The polymers prepared in the above examples and comparative examples were subjected to infrared testing using a Fourier transform infrared spectrometer (model: Thermo Scientific Nicolet iS50). The specific operation is as follows:

[0108] The polyether ketone powder samples obtained in the above examples and comparative examples were dried and then uniformly mixed with dried potassium bromide at a mass ratio of approximately 1:100. The mixture was then thoroughly ground using an agate mortar until the particle size was less than 2 micrometers to ensure effective transmission of infrared light. Subsequently, it was pressed into transparent sheets with a diameter of 13 mm under a pressure of 10 MPa. Before testing, a blank potassium bromide sheet was used as a background for scanning to eliminate environmental interference. During the formal testing, the spectral resolution was set to 4 cm⁻¹, and the number of scans was accumulated to 32 to optimize the signal-to-noise ratio. A deuterated sulfate triglycinate detector was used, with a scan wavenumber range covering 4000 to 400 cm⁻¹. All tests were conducted at room temperature, and atmospheric water and carbon dioxide interference was automatically eliminated using OMNIC software. Finally, the infrared absorption spectra of each sample in the vibrational frequency region of the characteristic functional groups were obtained. Figure 1 As shown. (Through) Figure 11 The infrared spectrum clearly shows that the PEKK main chain includes carbonyl groups, ether bonds and other structures, and the peak positions and peak heights are similar under different ratios.

[0109] like Figure 11 The infrared spectrum of PEKK shows a series of characteristic absorption peaks matching the target structure, specifically assigned as follows: 3065 cm⁻¹ -1 The peak at 1587 cm⁻¹ represents the stretching vibration of the CH bond in the benzene ring. -1 The absorption peak at 1495 cm⁻¹ corresponds to the vibrational characteristics of the benzene ring carbon skeleton (C=C). -1 The peak at 1660 cm⁻¹ is also a characteristic peak of the benzene ring, confirming the presence of an aromatic structure; -1 The peak at 1238 cm⁻¹ represents the stretching vibration of the carbonyl group (C=O), a position consistent with the typical characteristics of the carbonyl group in aromatic ketones. -1 The absorption peak at this point is attributed to the vibration of the ether bond (COC), confirming the presence of an aromatic ether structure in the molecular chain; the characteristic peak related to the benzene ring substituent is at 843 cm⁻¹. -1 The area around 873 cm⁻¹ is a typical absorption peak for para-substitution of aromatic rings, while... -1 780 cm -1 The absorption peaks appearing nearby are meta-substitution peaks of the benzene ring. The simultaneous appearance of all the above characteristic peaks, especially the meta-substitution characteristic peaks of the benzene ring originating from the terephthaloyl unit and the isophthaloyl unit respectively, is highly consistent with the theoretical structure of the PEKK copolymer obtained by copolymerization of terephthaloyl chloride, isophthaloyl chloride and diphenyl ether monomer, confirming that the product has the expected copolymer chemical structure.

[0110] The molecular weights of the products obtained in the above embodiments and comparative examples were determined.

[0111] Molecular weight distribution was determined using a high-temperature gel permeation chromatography (TPC) instrument at C0.05. 10H7Cl was used as the mobile phase, and a PLgel Olexis column with a total length of 650 mm was used for the test.

[0112] The test conditions were as follows: mobile phase refractive index (RI) of 1.631, flow rate of 1 mL / min, temperature of 150 °C, injection volume of 200 μL, sample concentration of 0.1 mg / mL, and a differential refractive index detector (RI).

[0113] The test parameters were set to K=14.1 and α=0.7. A narrow-distribution standard sample was used for calibration, and the calibration curve was a first-order polynomial.

[0114] logM = a + b RT (RT is the retention time, in minutes).

[0115] Wherein, coefficients a = 13.07, b = -0.591803, and the linear correlation coefficient is -0.99881, and data processing was performed using Cirrus 3.4 software. The molecular weight distribution diagrams of the above embodiments and comparative examples are shown below. Figure 2-10 As shown in Table 1 below, the test results are as follows:

[0116] Table 1

[0117]

[0118] Based on the test results above, the polymer prepared by the method proposed in this application has a high molecular weight and a narrow molecular weight distribution. Further optimization of the programmed temperature control parameters, such as the heating rate, can further increase the molecular weight of the prepared polymer and narrow its molecular weight distribution.

[0119] In particular, Comparative Example 3 changed the order of feeding, adding aluminum trichloride first and then DMF. The binding ability of DMF to aluminum trichloride is stronger than that of aluminum trichloride to acyl chloride, which will destroy the already formed acyl chloride-aluminum trichloride active complex, resulting in a reduction of catalytic active species and an increase in side reactions. Therefore, the synthesis effect is worse than that of Example 1.

[0120] Therefore, it can be seen that by controlling the order of raw material feeding and temperature control during the synthesis process, and by removing HCl through inert gas purging, this application can obtain polyether ketones with larger molecular weight and narrower molecular weight distribution. Thus, it can improve the performance of the obtained polymer, making it widely applicable in aerospace, electronics, instrumentation, medical, automotive manufacturing, and energy fields.

[0121] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application 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 therein. 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 this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for preparing polyetherketoneketone, characterized in that, The method includes the following steps: (1) The raw materials are mixed at a first temperature. The raw materials include acyl chloride, solvent, Lewis base, diphenyl ether and Lewis acid. The order of feeding the raw materials is acyl chloride, solvent, Lewis base, diphenyl ether and Lewis acid. After keeping warm, the mixture is raised to a second temperature to carry out the first reaction stage. (2) The reaction product of step (1) is heated to a third temperature to carry out the second reaction stage; (3) Add a terminator to the reaction mixture from step (2); in: The third temperature is greater than the second temperature, and the second temperature is greater than the first temperature. The heating rates in steps (1) and (2) are independently 0.1~5℃ / min, the first temperature is -25℃~-10℃, the second temperature is -5℃~5℃, and the third temperature is 20~35℃. The reaction process was carried out under conditions of inert gas purging. The polyether ketone prepared by the method has a weight-average molecular weight between 5,000 and 200,000, and a molecular weight distribution coefficient between 2.5 and 4.

5. The inert gas is selected from nitrogen, argon, or neon; The molar ratio of the solvent to the acyl chloride is 2:1 to 30:1; The molar ratio of the Lewis base to the acyl chloride is from 1:1 to 3.5:1; The molar ratio M of the added Lewis acid to the sum of the added acyl chloride and Lewis base is... 路易斯酸 :(M 酰氯 +M 路易斯碱 The ratio ranges from 1.1:1 to 3.0:

1. The molar ratio of the acyl chloride to the Lewis base is 1:1 to 1:4; The molar ratio of the diphenyl ether to the acyl chloride is from 0.8:1 to 1.2:

1.

2. The method according to claim 1, characterized in that, The acyl chloride is selected from one, two, or three of terephthaloyl chloride, orthophthaloyl chloride, and isophthaloyl chloride; The Lewis base is selected from one, two or more of N,N-dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; The Lewis acid includes one, two, or more of the following: anhydrous aluminum trichloride, anhydrous ferric trichloride, boron trifluoride, anhydrous zinc dichloride, anhydrous antimony pentachloride, and anhydrous tin dichloride; The solvent includes one, two, or more of dichloromethane, dichloroethane, o-dichlorobenzene, carbon disulfide, and nitrobenzene.

3. The method according to claim 1, characterized in that, The heating rates in steps (1) and (2) are each 0.1~2℃ / min.

4. The method according to claim 3, characterized in that, The method satisfies at least one of the following conditions: Step (1) further includes raising the temperature from the first temperature to the second temperature at a rate of 0.1~1℃ / min; and / or Step (2) also includes raising the temperature from the second temperature to the third temperature at a rate of 1~2℃ / min.

5. The method according to claim 1, characterized in that, The heat preservation time after the raw materials are mixed at the first temperature is 0.5-2 hours.

6. The method according to claim 1, characterized in that, The reaction time for the first reaction stage is 0.5-1.5 hours, and / or The reaction time for the second reaction stage is 3-5 hours.

7. The method according to claim 1, characterized in that, In step (3), after the second reaction stage is completed, stop stirring and add hydrochloric acid as a terminator, and let stand for 4-10 hours.

8. The method according to claim 1, characterized in that, The mixing of the raw materials, as well as the first and second reaction stages, are all carried out under stirring. The mixing speed of the raw materials is 200-350 rpm, and / or The stirring rate in the first reaction stage is 200-400 rpm, and / or The stirring rate in the second reaction stage is 100-400 rpm.

9. The method according to claim 1, characterized in that, The method further includes: sequentially crushing, sieving, and washing the product obtained in the second reaction stage. The crushing process includes grinding and pulverizing. The washing process includes water washing, organic solvent washing, and acid washing.

10. Use of polyetherketoneketone in the preparation of functional components, including components for use in aerospace systems, electrical and electronic systems, instrumentation, medical devices, automobiles, lithium-ion batteries, solar cells, or energy transmission systems. The polyether ketone is prepared using the method described in any one of claims 1-9.

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