Composite material containing high-temperature-resistant PEKK coating and preparation method thereof

Abstract

The invention discloses a composite material containing a high-temperature-resistant PEKK coating and a preparation method of the composite material. The preparation method comprises the following steps: step 1, treating the surface of a base material through normal-pressure plasma; step 2, preparing a PEKK coating, wherein the PEKK coating is prepared from the following raw materials in percentage by mass: 1-15wt% of PEKK powder, 1-15wt% of a dispersing agent, 1-15wt% of a dispersing agent and the balance 8 to 10 wt% of a cosolvent; 2-6 wt% of a dispersant; 0.1 to 0.5 wt% of a thickening agent; and the balance of deionized water. And 3, uniformly coating the PEKK coating on the surface of the substrate subjected to plasma treatment, and sintering at high temperature to obtain the composite material. A base material is modified by adopting a normal-pressure plasma surface treatment technology, surface chemical reconstruction is initiated through high-energy particle bombardment, and polar functional groups such as hydroxyl and carboxyl are directionally introduced; and meanwhile, a controllable etching effect is generated, and a micron-nano graded rough structure is constructed. And the interface bonding performance between the base material and the coating is obviously improved.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of material preparation, and in particular to a composite material comprising a high-temperature-resistant PEKK coating and a preparation method thereof. BACKGROUND

[0002] Advanced composite materials have become the first choice for "weight reduction and efficiency improvement" due to their high specific strength, high specific modulus, good designability and other performance advantages, promoting the active development of high-end equipment manufacturing industry. The application amount of composite materials has become one of the main indicators to measure the advanced degree of equipment manufacturing. In order to not damage the chemical structure of the fiber or film itself and avoid the decline of mechanical properties due to damage, coating on the surface of the fiber or film has more obvious advantages compared with other modification technologies. Moreover, the hierarchical structure created on the surface of the fiber or film is considered to be permanent, which can have a longer storage time.

[0003] Polyether ketone ketone (PEKK) is a semi-crystalline thermoplastic resin with excellent processability. In addition, it also has excellent heat resistance, chemical corrosion resistance, mechanical properties, and excellent dimensional stability and biocompatibility, and has become one of the highest performance thermoplastic resins in the world, and is widely used in national defense, aerospace, medical repair and other fields. However, except for a few extremely strong heat-dissolving media such as concentrated sulfuric acid, PEKK is basically insoluble in other organic synthetic media. It is necessary to develop a stable PEKK aqueous dispersion to meet the current industrial demand.

[0004] In addition, whether it is a fiber or a film, its surface is chemically inert, which seriously restricts its industrial application. SUMMARY

[0005] In view of this, the present disclosure provides a composite material comprising a high-temperature-resistant PEKK coating and a preparation method thereof, so as to greatly improve the service temperature of the composite material.

[0006] In a first aspect, the present disclosure provides a preparation method of a composite material comprising a high-temperature-resistant PEKK coating, comprising: step 1: treating the surface of a substrate by atmospheric pressure plasma;

[0007] Step 2: preparing a PEKK coating, wherein the PEKK coating is made of the following mass percentage raw materials: PEKK powder: 1-15wt%;co-solvent: 8-10wt%;dispersant: 2-6wt%;thickener: 0.1-0.5wt%;the rest is deionized water;

[0008] Step 3: uniformly coating the PEKK coating on the surface of the plasma-treated substrate, and sintering it at high temperature to obtain the composite material.

[0009] Preferably, the deionized water, cosolvent and dispersant are stirred and mixed uniformly, the PEKK powder is slowly added in batches under continuous stirring, after the system forms a uniform suspension, heating and constant temperature stirring, finally the thickening agent is slowly added to the system, after cooling to room temperature, the PEKK coating is prepared.

[0010] Preferably, the substrate in step 1 includes one of carbon fiber, aramid fiber, glass fiber, polyethylene fiber, polyimide film, polytetrafluoroethylene film, and polypropylene film.

[0011] Preferably, before the surface treatment of the substrate in step 1, the surface of the substrate is pretreated, including:

[0012] 1) The surface of the substrate is first cleaned with a solvent, and then washed with deionized water;

[0013] 2) The substrate is heated and dried, vacuum drying is used, the temperature is 100-120℃, and the time is 20-30min.

[0014] Preferably, in step 1, the process of atmospheric pressure plasma treatment is: the distance between the plasma electrode and the surface of the substrate is 3-6mm, the operating power is 600-1000W, and the plasma treatment speed is 4-12mm / s; wherein, the plasma is atmospheric pressure continuous plasma, and the gas used to excite the plasma is air.

[0015] Preferably, the preparation of the PEKK coating in step 2 includes the following steps:

[0016] The deionized water, cosolvent and dispersant are stirred and mixed uniformly, the PEKK powder is slowly added in batches under continuous stirring, after the system forms a uniform suspension, heating and constant temperature stirring, finally the thickening agent is slowly added to the system, after cooling to room temperature, the PEKK coating is prepared;

[0017] Preferably, the cosolvent is one or more of ethanol, ethylene glycol, and ethylene glycol ether;

[0018] The dispersant is one of AFCONA-5071, BYK-192, and BYK-190;

[0019] The thickening agent is one or more of hydroxypropyl methyl cellulose, xanthan gum, and polyvinylpyrrolidone;

[0020] The PEKK powder is a low crystalline polyether ketone ketone resin with a particle size of 1000 mesh;

[0021] Preferably, the stirring speed of the mixture of deionized water, cosolvent and dispersant is 200-600r / min, and the stirring time is 20-30min;

[0022] Control the slow addition of PEKK powder in 1-1.5h:

[0023] After the system forms a uniform suspension, heat and keep constant temperature stirring, heat the temperature to 80-85℃, add thickening agent to the system within 20-30min.

[0024] Preferably, the high-temperature sintering process in step 3 is at a temperature of 350-390℃ for 20-25min.

[0025] In a second aspect, the present application also provides a composite material comprising a high-temperature-resistant PEKK coating prepared by the above preparation method.

[0026] The present application provides a composite material comprising a high-temperature-resistant PEKK coating and a preparation method thereof, which has the following beneficial effects:

[0027] 1) The substrate surface is treated by atmospheric pressure plasma, which improves the density of polar groups on the substrate surface and the wettability through chemical grafting and physical etching, forms a micro-nano composite rough structure, and forms a mechanical interlocking effect with the PEKK coating, improves the interfacial adhesion strength through chemical bonding.

[0028] 2) The solution method used in the prior art to prepare the PEKK coating has the problems of difficulty in fully dissolving the conventional solvent and easy evaporation of the solvent during high-temperature dissolution. The present application proposes to prepare a water-based PEKK coating, which is green and environmentally friendly, and has high adhesion strength with the substrate PI film. The PEKK coating is still uniformly dispersed and stable in nature after 6 months of storage.

[0029] 3) The continuous coupling technology of atmospheric pressure plasma online treatment and coating process meets the requirements of industrial production, is efficient, and effectively avoids the influence of the time effect of plasma modification on the interfacial properties of the composite material.

[0030] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the disclosure of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0031] The drawings herein are incorporated into the specification and form part of the specification, show embodiments consistent with the present application, and together with the specification serve to explain the principles of the present application.

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiment or prior art description will be briefly introduced below, and obviously, other drawings can also be obtained by those skilled in the art without creative labor.

[0033] Figure 1 An infrared spectrum of the PEKK coating provided by the disclosed embodiments. DETAILED DESCRIPTION

[0034] The exemplary embodiments will be described in detail herein with reference to the accompanying drawings. In the following description, unless otherwise indicated, like numbers in the different drawings represent the same or similar elements. The following exemplary embodiments described are not meant to represent all embodiments consistent with the present application. Rather, they are merely examples of systems consistent with some aspects of the present application as detailed in the appended claims.

[0035] The method for preparing the composite material comprising the high-temperature-resistant PEKK coating of the present application comprises the following steps: first, modifying the substrate by using atmospheric pressure plasma surface treatment technology, initiating surface chemical reconstruction by high-energy particle bombardment, and introducing polar functional groups such as hydroxyl and carboxyl groups in a directional manner, while generating a controllable etching effect to build a micron-nanometer hierarchical rough structure. The interfacial adhesion between the substrate and the coating is significantly improved. The PEKK coating has uniform dispersion and long-term storage stability of more than 6 months.

[0036] The method for preparing the composite material comprising the high-temperature-resistant PEKK coating of the present application comprises the following steps:

[0037] Step 1: Atmospheric pressure plasma modification: wash off the dust and impurities on the surface of the substrate and dry it under vacuum heating. Fix the fiber or film on the plasma operation table according to the set height, power and speed for processing.

[0038] The above-mentioned substrate includes but is not limited to carbon fiber, aramid fiber, glass fiber, polyethylene fiber, polyimide film, polytetrafluoroethylene film, and polypropylene film.

[0039] The washing method is as follows: use a solvent to clean the surface of the film in a fume hood. The organic solvent is one or a combination of anhydrous ethanol, methanol, and acetone. Then rinse the surface with deionized water.

[0040] The vacuum drying temperature is 100-120℃, and the time is 20-30min.

[0041] The plasma treatment process is as follows: the distance between the plasma electrode and the surface of the substrate is 3-6mm, the operating power is 600-1000W, and the plasma treatment speed is 4-12mm / s. The plasma is an atmospheric continuous plasma, and the gas used to excite the plasma is air.

[0042] S2: Preparation of PEKK coating: Deionized water, cosolvent and dispersant were added into a three-necked flask in turn, and stirred at a constant speed until mixed uniformly. Then PEKK powder was slowly added in portions under continuous stirring, and after the system formed a uniform suspension, the heating device was turned on and constant temperature stirring was maintained. Finally, thickening agent was slowly added into the system. After cooling to room temperature, the preparation of PEKK coating was completed.

[0043] The cosolvent is one or more of ethanol, ethylene glycol, ethylene glycol ether, preferably ethanol.

[0044] The dispersant is any one of AFCONA-5071, BYK-192, BYK-190, preferably BYK-192.

[0045] The thickening agent is one or more of hydroxypropyl methylcellulose, xanthan gum, polyvinylpyrrolidone, preferably xanthan gum.

[0046] The stirring speed of the mixed solution of deionized water, cosolvent and dispersant is 200-600 r / min, and the stirring time is 20-30 min.

[0047] The PEKK powder is a low crystalline polyether ketone ketone resin with a particle size of 1000 mesh.

[0048] The PEKK powder is slowly added within 1-1.5 h.

[0049] The heating device is turned on, and after the temperature is heated to 80-85℃, the thickening agent is added into the system within 20-30 min.

[0050] The PEKK aqueous dispersion is made from the following mass percentage raw materials:

[0051] PEKK powder: 1-15 wt%

[0052] Cosolvent: 8-10 wt%

[0053] Dispersant: 2-6 wt%

[0054] Thickening agent: 0.1-0.5 wt%

[0055] The rest is deionized water.

[0056] S3: Coating modification

[0057] The PEKK coating is uniformly coated onto the surface of the plasma-treated substrate, and placed in a high temperature oven for high temperature sintering.

[0058] The high temperature sintering process is at a temperature of 350-390℃ for 20-25 min.

[0059] From Figure 1It can be seen that the PEKK coating prepared by the preparation method does not generate new groups and does not affect the performance of the material itself; the wettability of the substrate surface is improved by modification, and the plasma treatment technology can effectively improve the surface properties through the dual mechanisms of introducing polar groups and physical etching, and after the carbon fiber surface coated with the PEKK coating is treated by the plasma, a gradient temperature-resistant structure can be formed, and the interface region is significantly optimized. Especially the interface stability, mechanical property retention rate and long-term durability in harsh high-temperature environments are effectively improved.

[0060] The application will be further explained and described below in combination with specific embodiments, but is not used to limit the protection scope of the application.

[0061] Example 1

[0062] (1) Atmospheric pressure plasma modification

[0063] The carbon fiber surface is washed with acetone to remove dust and impurities, and then washed with deionized water. Heat to 100 DEG C and dry for 20 min.

[0064] The carbon fiber is fixed on the plasma operation table, the distance between the plasma electrode and the carbon fiber surface is set to 3 mm, the operation power is 600 W, the plasma treatment speed is 4 mm / s, and the gas for exciting the plasma is air.

[0065] (2) Preparation of PEKK coating

[0066] Deionized water, cosolvent anhydrous ethanol and dispersant BYK192 are sequentially added to a three-necked flask, and stirred at a constant speed of 200 r / min for 20 min until they are uniformly mixed. Among them, the deionized water is 86.9wt%, the cosolvent is 8wt%, and the dispersant is 2wt%. Then, under the condition of continuous stirring, 1wt% PEKK powder is slowly added in batches within 1h. After the system forms a uniform suspension, the heating device is turned on, heated to 80 DEG C and kept at constant temperature stirring. Finally, 0.1wt% thickener is slowly added to the system within 30 min.

[0067] After cooling to room temperature, the preparation of the PEKK coating is completed.

[0068] (3) Coating modification

[0069] The PEKK coating is uniformly dispersed on the surface of the carbon fiber treated by the plasma, and then placed in a high-temperature oven at 350 DEG C for high-temperature sintering, and the sintering time is 20 min.

[0070] Example 2

[0071] (1) Atmospheric pressure plasma modification

[0072] The aramid fiber surface dust impurities were washed away with acetone, and the surface was rinsed with deionized water. Heat to 100°C, dry for 20 min.

[0073] The aramid fiber was fixed on the plasma operation table, the distance between the plasma electrode and the surface of the aramid fiber was set to 4 mm, the operation power was 700 W, the plasma treatment speed was 6 mm / s, and the gas for exciting the plasma was air.

[0074] (2) Preparation of PEKK coating

[0075] Deionized water, cosolvent anhydrous ethanol and dispersant BYK192 were added into a three-necked flask in turn, and stirred at a constant speed of 300 r / min for 20 min until mixed uniformly. Among them, deionized water is 84.7wt%, cosolvent 9wt%, dispersant 3wt%. Then under the condition of continuous stirring, 3wt% PEKK powder was slowly added in batches within 1h. After the system forms a uniform suspension, start the heating device, heat to 80°C and keep constant temperature stirring. Finally, 0.3wt% thickener is slowly added to the system within 30 min.

[0076] After cooling to room temperature, the preparation of PEKK coating is completed.

[0077] (3) Coating modification

[0078] The PEKK coating was uniformly dispersed on the surface of the plasma treated aramid fiber, and placed in a high temperature oven at 360°C for high temperature sintering, and the sintering time was 20 min.

[0079] Example 3

[0080] (1) Atmospheric pressure plasma modification

[0081] The glass fiber surface dust impurities were washed away with acetone, and the surface was rinsed with deionized water. Heat to 100°C, dry for 20 min.

[0082] The glass fiber was fixed on the plasma operation table, the distance between the plasma electrode and the surface of the glass fiber was set to 5 mm, the operation power was 800 W, the plasma treatment speed was 8 mm / s, and the gas for exciting the plasma was air.

[0083] (2) Preparation of PEKK coating

[0084] Deionized water, cosolvent anhydrous ethanol and dispersant BYK192 were added into a three-necked flask in turn, and stirred at a constant speed of 400 r / min for 20 min until mixed uniformly. Among them, deionized water was 80.7wt%, cosolvent 10wt%, and dispersant 4wt%. Then, 5wt% PEKK powder was slowly added in batches under constant stirring within 1h. After the system formed a uniform suspension, the heating device was turned on, heated to 80℃ and kept constant temperature stirring. Finally, 0.3wt% thickener was slowly added to the system within 30 min.

[0085] After cooling to room temperature, the preparation of PEKK coating was completed.

[0086] (3) Coating modification

[0087] The PEKK coating was uniformly dispersed onto the surface of the plasma-treated glass fiber, and placed in a high-temperature oven at 370℃ for high-temperature sintering, with a sintering time of 20 min.

[0088] Example 4

[0089] (1) Atmospheric pressure plasma modification

[0090] The PI film was washed with anhydrous ethanol to remove dust and impurities on the surface, and heated to 80℃ for 20 min.

[0091] The PI film was fixed on the plasma operation table, the distance between the plasma electrode and the surface of the PI film was set to 6mm, the operation power was 900W, the plasma treatment speed was 10mm / s, and the gas for exciting plasma was air.

[0092] (2) Preparation of PEKK coating

[0093] Deionized water, cosolvent anhydrous ethanol and dispersant BYK192 were added into a three-necked flask in turn, and stirred at a constant speed of 500 r / min for 20 min until mixed uniformly. Among them, deionized water was 76.7wt%, cosolvent 8wt%, and dispersant 5wt%. Then, 10wt% PEKK powder was slowly added in batches under constant stirring within 1h. After the system formed a uniform suspension, the heating device was turned on, heated to 80℃ and kept constant temperature stirring. Finally, 0.3wt% thickener was slowly added to the system within 30 min.

[0094] After cooling to room temperature, the preparation of PEKK coating was completed.

[0095] (3) Coating modification

[0096] The PEKK coating was uniformly dispersed onto the surface of the plasma-treated PI film, and placed in a high-temperature oven at 380℃ for high-temperature sintering, with a sintering time of 25 min.

[0097] Example 5

[0098] (1) Atmospheric plasma modification

[0099] The PTFE film was washed with anhydrous ethanol to remove dust and impurities on the surface, and then heated to 80°C and dried for 20 min.

[0100] The PTFE film was fixed on the plasma operation table, the distance between the plasma electrode and the surface of the PTFE film was set to 4 mm, the operation power was 1000 W, the plasma treatment speed was 12 mm / s, and the gas for exciting the plasma was air.

[0101] (2) Preparation of PEKK coating

[0102] Deionized water, cosolvent anhydrous ethanol and dispersant BYK192 were added into a three-necked flask in turn, and stirred at a constant speed of 600 r / min for 20 min until they were uniformly mixed. Among them, the deionized water was 69.7 wt%, the cosolvent was 9 wt%, and the dispersant was 6 wt%. Then, under continuous stirring, 15 wt% PEKK powder was slowly added in portions within 1 h. After the system formed a uniform suspension, the heating device was turned on, heated to 80°C and kept at constant temperature stirring. Finally, 0.3 wt% thickener was slowly added to the system within 30 min.

[0103] After cooling to room temperature, the preparation of PEKK coating was completed.

[0104] (3) Coating modification

[0105] The PEKK coating was uniformly scraped onto the surface of the plasma-treated PTFE film by scraping, and then placed in a high-temperature oven at 390°C for high-temperature sintering, with a sintering time of 25 min.

[0106] Comparative Example 1

[0107] A method for preparing a composite material comprising a high-temperature-resistant PEKK coating, which is the same as Example 4, except that step (2) for preparing the PEKK coating is as follows:

[0108] Deionized water was added into a three-necked flask, and stirred at a constant speed of 600 r / min. Under continuous stirring, 10 wt% PEKK powder was slowly added in portions within 3 h. After the system formed a uniform suspension, 0.3 wt% thickener was slowly added to the system within 30 min. After cooling to room temperature, the preparation of PEKK coating was completed.

[0109] The PEKK coating obtained above was not uniformly dispersed, and there were a large number of lumps. After being placed for 24 h, the coating was stratified and formed a precipitate.

[0110] Comparative Example 2:

[0111] A method for preparing a composite material comprising a high-temperature-resistant PEKK coating, as in Example 4, except that step (2) is used to prepare the PEKK coating:

[0112] Deionized water and a cosolvent, anhydrous ethanol, were added to a three-necked flask and stirred at a constant speed of 600 r / min for 20 min until they were uniformly mixed. The deionized water accounted for 80.7 wt%, and the cosolvent accounted for 9 wt%. Under the condition of continuous stirring, 10 wt% of PEKK powder was slowly added in portions within 3 h. After the system formed a uniform suspension, 0.3 wt% of a thickening agent was slowly added to the system within 30 min.

[0113] After being reduced to room temperature, the preparation of the PEKK coating was completed. The obtained PEKK coating was not uniformly dispersed, still had lumps, and after being placed for 96 h, the coating was stratified to form a precipitate.

[0114] Comparative Example 3:

[0115] A method for preparing a composite material comprising a high-temperature-resistant PEKK coating, as in Example 4, except that step (2) is used to prepare the PEKK coating:

[0116] In a fume hood, trifluoroacetic acid (TFA) and 1,2-dichloroacetic acid (DCA) were mixed in a volume ratio of 8:2. The mixed solvent was added to a three-necked flask, and PEKK was slowly added in portions within 4 h while stirring at a constant speed of 600 r / min. After the system formed a uniform solution, the PEKK coating was obtained. The obtained PEKK coating was yellow, and after being placed for 24 h, the coating was stratified to form a precipitate. In addition, trifluoroacetic acid (TFA) and 1,2-dichloroacetic acid (DCA) used have strong volatility and irritation, and are not suitable for industrial production.

[0117] Comparative Example 4:

[0118] A method for preparing a composite material comprising a high-temperature-resistant PEKK coating, as in Example 4, except that step (2) is used to prepare the PEKK coating:

[0119] After the PEKK powder was dried, it was mixed with concentrated sulfuric acid in a mass ratio of 1:10 and heated at 100°C for 6 h. After the reaction was completed, it was placed in an ice water bath for displacement reaction. After standing, the precipitate was taken and washed repeatedly with deionized water until the deionized water was neutral. After vacuum drying to completely remove the water, SPEKK powder was obtained. The degree of sulfonation was measured by acid-base titration to be 10-14%. The SPEKK powder was dissolved in water to prepare a coating with a concentration of 10 wt%.

[0120] The obtained PEKK coating is uniformly dispersed, but the sulfonation process significantly reduces the temperature resistance of PEKK while improving the dispersibility of PEKK molecules in water. The introduction of sulfonic acid groups (-SO3H) on the PEKK molecular chain, the steric hindrance of these polar groups is large, which will destroy the original regular arrangement of the molecular chain. The heat resistance of PEKK depends on the highly ordered packing of molecular chains (such as crystalline structure), after the regularity is destroyed, the tightness between molecular chains decreases, and the melting temperature and thermal stability decrease. In addition, the complex process flow is not suitable for industrial production.

[0121] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the application being indicated by the following claims.

Claims

1. A method for preparing a composite material comprising a high temperature resistant PEKK coating, characterized in that: Step 1: Treat the substrate surface by atmospheric pressure plasma; Step 2: preparing a PEKK coating, wherein the PEKK coating is made of the following raw materials in percentage by weight: PEKK powder: 1-15 wt%; co-solvent: 8-10 wt%; Dispersant: 2-6wt%; Thickener: 0.1-0.5wt%; The rest is deionized water; Step 3: uniformly coating the PEKK coating on the surface of the plasma-treated substrate, and sintering it at a high temperature to obtain the composite material.

2. The method for preparing a composite material comprising a high temperature resistant PEKK coating according to claim 1, characterized in that: Deionized water, cosolvent and dispersant were stirred and mixed evenly, and PEKK powder was slowly added in small amounts under continuous stirring. After the system formed a uniform suspension, it was heated and stirred at a constant temperature. Finally, a thickener was slowly added to the system and cooled to room temperature to prepare a PEKK coating.

3. The method for preparing a composite material comprising a high temperature resistant PEKK coating according to claim 1, characterized in that: The substrate in step 1 includes one of carbon fiber, aramid fiber, glass fiber, polyethylene fiber, polyimide film, polytetrafluoroethylene film, and polypropylene film.

4. The method for preparing a composite material comprising a high temperature resistant PEKK coating according to claim 1, characterized in that: Before treating the substrate surface with atmospheric pressure plasma in step 1, the substrate surface is pretreated, including: 1) Clean the substrate surface with a solvent and then rinse with deionized water; 2) The substrate is heated and dried by vacuum drying at a temperature of 100-120° C. for 20-30 minutes.

5. The method for preparing a composite material comprising a high temperature resistant PEKK coating according to claim 1, wherein: In step 1, the process of atmospheric pressure plasma treatment is as follows: the distance between the plasma electrode and the substrate surface is 3-6 mm, the operating power is 600-1000 W, and the plasma treatment speed is 4-12 mm / s; wherein, the plasma is atmospheric pressure continuous plasma, and the gas used to excite the plasma is air.

6. The method for preparing a composite material comprising a high temperature resistant PEKK coating according to claim 1, characterized in that: The PEKK coating is prepared in step 2, comprising the following steps: Deionized water, cosolvent and dispersant were stirred and mixed evenly, and PEKK powder was slowly added in small amounts under continuous stirring. After the system formed a uniform suspension, it was heated and stirred at a constant temperature. Finally, a thickener was slowly added to the system and cooled to room temperature to prepare a PEKK coating.

7. The method for preparing a composite material comprising a high temperature resistant PEKK coating according to claim 1, characterized in that: The cosolvent is one or more of ethanol, ethylene glycol, and ethylene glycol ether; The dispersant is one of AFCONA-5071, BYK-192, and BYK-190; The thickener is one or more of hydroxypropyl methylcellulose, xanthan gum, and polyvinyl pyrrolidone; The PEKK powder is a low-crystalline polyetherketoneketone resin with a particle size of 1000 mesh.

8. The method for preparing a composite material comprising a high temperature resistant PEKK coating according to claim 6, characterized in that: The deionized water, cosolvent and dispersant are mixed at a stirring speed of 200-600 r / min and a stirring time of 20-30 min; Slowly add PEKK powder in 1-1.5 hours: After the system forms a uniform suspension, the system is heated and kept at a constant temperature while stirring until the temperature reaches 80-85° C., and the thickener is added to the system within 20-30 minutes.

9. The method for preparing a composite material comprising a high temperature resistant PEKK coating according to claim 1, characterized in that: The high temperature sintering process in step 3 is performed at a temperature of 350-390° C. and a time of 20-25 minutes.

10. A composite material comprising a high temperature resistant PEKK coating prepared according to the preparation method according to any one of claims 1 to 9.

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