Fiber surface high-temperature-resistant thermoplastic aqueous solution sizing agent and preparation process thereof

Abstract

The invention discloses a fiber reinforced composite material and a preparation process thereof, and aims to provide a fiber surface high-temperature-resistant thermoplastic aqueous solution sizing agent and a preparation process thereof, and fiber surface sizing treatment of the thermoplastic sizing agent can be realized by utilizing a sizing process of thermosetting resin. The sizing agent has the characteristics of easy sizing treatment and high sizing agent treatment uniformity of a thermosetting sizing agent, also has compatibility and heat resistance of thermoplastic high-temperature-resistant resin, and has the key points of the technical scheme that a prepolymer of PEEK is used as a main component of the sizing agent, so that the dissolving property is relatively good, and the sizing agent can be used as a high-temperature-resistant sizing agent. The preparation method comprises the following steps: preparing a PEEK prepolymer, adding a surfactant for improving the hydrophilicity and lipophilicity of the PEEK prepolymer into the PEEK prepolymer to form a PEEK graft polymerization product so as to improve the emulsification, dispersion and wettability of the PEEK prepolymer in an aqueous medium, and grinding the PEEK graft polymerization product into nano-scale fine powder. The preparation method disclosed by the invention is suitable for the field of preparation of fiber reinforced composite materials.

Description

Technical Field

[0001] The present invention relates to a fiber reinforced composite material and a preparation process thereof, and more specifically, to a fiber surface high temperature resistant thermoplastic aqueous solution sizing agent and a preparation process thereof. Background Art

[0002] Fiber reinforced composite materials are composite materials systems formed by reinforcing fiber materials, such as glass fiber, carbon fiber, boron fiber, aramid fiber, polyethylene fiber and natural fiber, and matrix materials through winding, molding or extrusion injection molding and other molding processes. Since the stiffness and strength of pure resin matrix are relatively low, it does not have advantages in structural and semi-structural applications. The mechanical properties of the resin matrix can be improved by adding high stiffness and high strength fibers. Therefore, fiber reinforced composites have become an effective method to expand the application range of resin matrix. In addition, the traditional extrusion injection molding process of polymer resin matrix is ​​also applicable to fiber reinforced composite materials. The process is simple to operate, low in cost and widely used. By adding fiber reinforcement, when the composite material is subjected to force, the stress will be transferred from the matrix to the embedded fiber through the interface between the reinforcing fiber and the matrix, thereby improving the mechanical properties of the composite material, such as strength and modulus.

[0003] In order to develop high-performance fiber-reinforced composites, it is necessary to know the main factors that affect the performance of fiber-reinforced composites during the research process. Among them, the interface is the main influencing factor. The interface is the area where the reinforcing fiber and the matrix are combined, including the fiber, the matrix and the coating. It can be a diffusion area, a core area, a chemical reaction area or a fiber coating, etc., or it can be a community of these areas. The interface plays a decisive role in the process of stress transfer from the matrix to the fiber and is the main factor affecting the mechanical properties of the composite material. Therefore, in the process of short fiber reinforced composite modification, the fiber is often surface treated to improve the interfacial adhesion of the composite material, thereby improving the mechanical self-locking effect of the matrix on the reinforcing fiber, so as to achieve the purpose of effectively improving the performance of the composite material. Commonly used fiber surface treatment methods include electrochemical etching, chemical grafting modification, thermal oxidation, coating treatment and plasma treatment.

[0004] However, in the above-mentioned fiber surface treatment methods, physical etching and oxidation treatments will damage the fiber, thereby affecting the reinforcement effect; chemical grafting and chemical treatment are relatively difficult and the effect is not ideal. Only coating treatment is the most advantageous and feasible, and the traditional fiber surface coating treatment agent is mainly based on thermosetting resin solution, because the viscosity of thermosetting resin solution is low, sizing treatment is more convenient, and the treatment effect is also good, but the thermosetting resin sizing agent is usually epoxy resin, etc., which is not heat-resistant, especially for the fiber reinforcement modification of special engineering materials, because the processing temperature is usually above 350 ° C, the traditional epoxy and other thermosetting resin sizing agents are basically ineffective at this temperature, and can not play a role in improving the interface effect. In addition, in the fiber reinforcement modification, most of the resin matrix used is a thermoplastic resin matrix, which has poor compatibility with thermosetting materials such as epoxy, so the traditional thermosetting sizing agent is not ideal for the fiber reinforcement modification of high-temperature thermoplastic resins, and the application range is limited. However, due to the poor control of viscosity, it is difficult to form a uniform coating and an ideal coating effect by melt sizing with thermoplastic resin. Therefore, this patent relates to a treatment agent and its preparation process technology for coating fibers using a high-temperature resistant thermoplastic resin aqueous solution. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a high-temperature resistant thermoplastic aqueous solution sizing agent for fiber surface and a preparation process thereof. The sizing process of thermosetting resin can be used to achieve sizing treatment on the fiber surface of the thermoplastic sizing agent. The thermoplastic sizing agent has the characteristics of easy sizing treatment and high uniformity of sizing agent treatment of the thermosetting sizing agent, and also has the compatibility and heat resistance of the thermoplastic high-temperature resistant resin.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: A preparation process of a high-temperature resistant thermoplastic aqueous solution sizing agent for a fiber surface, comprising the following steps: S1, raw material preparation: a staff member prepares the main raw materials required for a nucleophilic substitution reaction, the raw materials being 4,4'-difluorobenzophenone (DFBP), hydroquinone (HQ) and potassium carbonate (K2CO3), and taking diphenyl sulfone (DPS) as the main reaction solvent;

[0007] S2. Obtaining the reaction ratio: preparing the molar amounts of DFBP and HQ in a molar ratio of 1:1, and calculating the molar amount of K2CO3 based on the molar amounts of DFBP and HQ, so that K2CO3:DFBP:HQ is 2.5:1:1, and calculating the mass of DPS based on the total mass of DFBP and HQ, so that the total mass of DFBP and HQ accounts for 25% of the mass of DPS;

[0008] S3, reaction mixing: pour the raw materials into the reactor for mixing, set the reaction temperature between 180-300° C., and continuously stir the raw materials during the mixing process. The reaction time is 20 hours to obtain a mixture;

[0009] S4. Preparation of PEEK prepolymer: After the reaction is completed, the mixture is cooled to room temperature, and dilute hydrochloric acid is poured into the mixture to precipitate the polymer to obtain the prepolymer;

[0010] S5. PEEK prepolymer extraction: filtering the mixture to obtain a polymer, and repeatedly washing with deionized water and an organic solvent to remove the raw material solvent and impurities to obtain a PEEK prepolymer;

[0011] S6, secondary polymerization: placing the PEEK prepolymer prepared in step S5 into a second reactor, and adding a hydrophilic and lipophilic surfactant into the reactor, so that the active functional groups of the hydrophilic and lipophilic surfactant react chemically with the PEEK prepolymer, thereby grafting the hydrophilic and lipophilic surfactant onto the PEEK polymer to form a PEEK grafted polymer product;

[0012] S7, aqueous solution mixing: grinding the PEEK grafted polymer product obtained in step S6 into nanometer scale, and adding water to form an aqueous solution sizing agent.

[0013] The present invention is further configured as follows: the hydrophilic and lipophilic active agent in step S6 is one of monoglyceride of fatty acid, polyoxyethylene fatty alcohol ether, polyoxyethylene-polyoxypropylene copolymer, sodium sulfate of fatty alcohol polyoxyethylene ether, sodium sulfate of alkylphenol polyoxyethylene ether, and dodecyl dimethyl hydroxyethyl ammonium chloride.

[0014] The present invention is further configured as follows: the step S6 further includes a grafting method of a PEEK polymer, comprising the following steps: S61, raising the temperature of the second reaction kettle to 180° C., and maintaining the temperature at 180° C. for 1 hour, while continuously stirring the mixture in the second reaction kettle;

[0015] S62, after 1 hour, continue to increase the temperature in the second reaction kettle to 200° C., and maintain it at 200° C. for 1 hour, while continuously stirring the mixture in the second reaction kettle;

[0016] S63. After 1 hour, continue to increase the temperature in the second reactor to 255 degrees Celsius and heat for 20 minutes. After 20 minutes, increase the temperature in the second reactor to 320 degrees Celsius and continue for 3 hours to form a PEEK grafted polymerization product.

[0017] The present invention is further configured as follows: the step S7 further includes a sizing process of a sizing agent, characterized in that it includes the following steps: S71, immersing the fiber bundle to be sized in an aqueous sizing agent for a soaking time of T;

[0018] S72, after a period of time T, taking out the fiber bundle in the aqueous sizing agent, and squeezing to remove most of the excess water and solution;

[0019] S73, drying the fiber bundle to further remove excess water and solution, and completing sizing of the fiber bundle.

[0020] The present application also provides a sizing agent produced based on the preparation process of the above-mentioned fiber surface high-temperature resistant thermoplastic aqueous solution sizing agent, wherein the sizing agent is composed of a prepolymer of polyetheretherketone (PEEK), a hydrophilic and lipophilic active agent and water.

[0021] Preferably, in the sizing agent, the hydrophilic and lipophilic active agents account for 55% of the total mass, the PEEK prepolymer accounts for 25% of the total mass, and water accounts for 20% of the total mass.

[0022] By adopting the above technical scheme, the beneficial effects are as follows: 1. Since polyetheretherketone (PEEK) is a typical water-insoluble material, any solvent except concentrated sulfuric acid cannot dissolve PEEK. In this application, the prepolymer of PEEK is used as the main component of the sizing agent. The prepolymer of PEEK is an intermediate product in the polymerization reaction of PEEK. Since the molecular chain is short and contains active end groups, it has good solubility and is easy to process. It can be better mixed with other additives or reinforcing materials, and a surfactant for increasing its hydrophilicity and lipophilicity is added to the prepolymer of PEEK to form a PEEK grafted polymerization product. The emulsification, dispersion and wetting properties of the PEEK prepolymer in an aqueous medium are improved, and the grafted polymerization product of PEEK is ground into nano-scale fine powder so that it can be evenly dispersed in a deionized water solution to form an evenly dispersed aqueous solution, so that the finished sizing agent has good water solubility, can reduce the surface tension of the sizing agent solution, and can better spread and penetrate on the fiber surface. In addition, the PEEK has excellent high temperature resistance, mechanical properties and chemical stability. As the main film-forming substance of the sizing agent, it can form a continuous and stable protective film on the fiber surface, thereby improving the heat resistance and wear resistance of the fiber.

[0023] 2. Further, in order to produce PEEK prepolymer to obtain the raw materials for the reaction, the PEEK prepolymer is usually prepared by nucleophilic substitution reaction. The raw materials are mainly 4,4'-difluorobenzophenone (DFBP), hydroquinone (HQ) and potassium carbonate (K2CO3), and diphenyl sulfone (DPS) is used as the main reaction solvent, and the molar ratio of DFBP to HQ is 1:1, which is conducive to the formation of a relatively regular linear molecular structure, so that the polymerization degree of the finished product is high, the molecular weight of the polymer is large, and the final prepolymer has certain lipophilicity and hydrophilicity. At the same time, in the production process, by The reaction temperature is set to be adjusted between 180-300℃. If the temperature is less than 180℃ during the reaction, the rate of nucleophilic substitution reaction or polycondensation reaction between DFBP and HQ is significantly lower, and the reaction takes a long time to reach a certain conversion rate. When the temperature is greater than 300℃, although the reaction rate may be further accelerated, it may also cause some side reactions, such as polymer degradation and cross-linking, thereby affecting the quality and performance of the prepolymer and even causing the reaction to run out of control. By setting the reaction temperature between 180-300℃, the collision frequency between the raw material molecules is increased, the reaction rate is accelerated, and it is beneficial to the formation of the prepolymer. At this time, the number of activated molecules in the reaction system increases, the effective collision probability increases, the reaction can proceed faster, and the production efficiency is improved. In addition, the raw materials are continuously stirred during the reaction, which can further increase the reaction rate.

[0024] 3. At the same time, in order to make the finished product have better water solubility, by adding a hydrophilic and lipophilic active agent into the PEEK prepolymer, the PEEK material can have better surface activity and its dispersibility in different phases (such as water phase and oil phase), and the hydrophilic and lipophilic active agent is one of monoglyceride, polyoxyethylene fatty alcohol ether, polyoxyethylene-polyoxypropylene copolymer, sodium sulfate of fatty alcohol polyoxyethylene ether, sodium sulfate of alkylphenol polyoxyethylene ether, and dodecyl dimethyl hydroxyethyl ammonium chloride, which can form a chemical bond between the hydrophilic and lipophilic active agent and the PEEK prepolymer. Compared with simple physical mixing, this chemical bonding method can make the material performance more stable. For example, in the long-term use process, the chemically bonded structure is not easy to phase separation. The PEEK grafted hydrophilic group forms a PEEK grafted polymer product, and the finished product is ground into nano-scale fine powder, so that it can be more evenly dispersed in water, further improving the uniformity of the solution. At the same time, in the process of grafting, the grafting temperature is set at 180-255°C and the cumulative heating is 2h20min, which can increase the collision frequency between the raw material molecules, greatly improve the effective collision probability, and achieve a higher conversion rate in a short time. Heating at a processing temperature of 320°C for 3h can enhance the interaction between the PEEK prepolymer and the hydrophilic and lipophilic surfactant, promote the mixing and compatibility of the two, make the polymer product form a more uniform phase structure, improve the overall performance of the product, and have a good processing effect and high processing efficiency.

[0025] 4. In order to improve the surface activity and dispersibility of the sizing agent as an aqueous solution and to improve the overall emulsification performance in an aqueous medium, it is necessary to increase the proportion of hydrophilic and lipophilic surfactants. Generally speaking, the hydrophilic and lipophilic surfactants account for 55% of the total mass, the PEEK prepolymer accounts for 25% of the total mass, and water accounts for 20% of the total mass. This can effectively reduce the surface tension of the product at the oil-water interface, play an emulsifying and dispersing role, and has good affinity with the limiting surface to form a suitable sizing solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a preparation process flow chart of a fiber surface high temperature resistant thermoplastic aqueous solution sizing agent and a preparation process embodiment thereof of the present invention;

[0027] Figure 2 It is a flow chart of a grafting method of a PEEK polymer of a fiber surface high temperature resistant thermoplastic aqueous solution sizing agent and a preparation process embodiment of the present invention;

[0028] Figure 3 The present invention is a flow chart of a sizing method for a fiber surface high temperature resistant thermoplastic aqueous solution sizing agent and a preparation process embodiment thereof. DETAILED DESCRIPTION

[0029] Reference Figures 1 to 3 The invention further describes a fiber surface high temperature resistant thermoplastic aqueous solution sizing agent and a preparation process example thereof.

[0030] For ease of explanation, spatial relative terms such as "upper", "lower", "left", "right" and the like are used in the embodiments to illustrate the relationship of one element or feature shown in the figure relative to another element or feature. It should be understood that, in addition to the orientation shown in the figure, the spatial terms are intended to include different orientations of the device in use or operation. For example, if the device in the figure is inverted, the element described as being "under" other elements or features will be positioned "on" other elements or features. Therefore, the exemplary term "under" can include both upper and lower orientations. The device can be positioned in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used here can be interpreted accordingly.

[0031] Furthermore, relational terms such as “first” and “second” and the like are merely used to distinguish one component from another having the same name, but do not necessarily require or imply any such actual relationship or order between these components.

[0032] A preparation process of a high temperature resistant thermoplastic aqueous solution sizing agent for a fiber surface, characterized in that it comprises the following steps: S1, raw material preparation: a staff member prepares the main raw materials required for a nucleophilic substitution reaction, the raw materials being 4,4'-difluorobenzophenone (DFBP), hydroquinone (HQ) and potassium carbonate (K2CO3), and taking diphenyl sulfone (DPS) as the main reaction solvent;

[0033] S2. Obtaining the reaction ratio: preparing the molar amounts of DFBP and HQ in a molar ratio of 1:1, and calculating the molar amount of K2CO3 based on the molar amounts of DFBP and HQ, so that K2CO3:DFBP:HQ is 2.5:1:1, and calculating the mass of DPS based on the total mass of DFBP and HQ, so that the total mass of DFBP and HQ accounts for 25% of the mass of DPS;

[0034] S3, reaction mixing: pour the raw materials into the reactor for mixing, set the reaction temperature between 180-300° C., and continuously stir the raw materials during the mixing process. The reaction time is 20 hours to obtain a mixture;

[0035] S4. Preparation of PEEK prepolymer: After the reaction is completed, the mixture is cooled to room temperature, and dilute hydrochloric acid is poured into the mixture to precipitate the polymer to obtain the prepolymer;

[0036] S5. PEEK prepolymer extraction: filtering the mixture to obtain a polymer, and repeatedly washing with deionized water and an organic solvent to remove the raw material solvent and impurities to obtain a PEEK prepolymer;

[0037] S6, secondary polymerization: placing the PEEK prepolymer prepared in step S5 into a second reactor, and adding a hydrophilic and lipophilic surfactant into the reactor, so that the active functional groups of the hydrophilic and lipophilic surfactant react chemically with the PEEK prepolymer, thereby grafting the hydrophilic and lipophilic surfactant onto the PEEK polymer to form a PEEK grafted polymer product;

[0038] S7, aqueous solution mixing: grinding the PEEK grafted polymer product obtained in step S6 into nanometer scale, and adding water to form an aqueous solution sizing agent.

[0039] The hydrophilic and lipophilic active agent in step S6 is one of monoglyceride of fatty acid, polyoxyethylene fatty alcohol ether, polyoxyethylene-polyoxypropylene copolymer, sodium sulfate of fatty alcohol polyoxyethylene ether, sodium sulfate of alkylphenol polyoxyethylene ether, and dodecyl dimethyl hydroxyethyl ammonium chloride.

[0040] The step S6 also includes a grafting method of a PEEK polymer, comprising the following steps: S61, raising the temperature of the second reaction kettle to 180° C., and maintaining the temperature at 180° C. for 1 hour, while continuously stirring the mixture in the second reaction kettle;

[0041] S62, after 1 hour, continue to increase the temperature in the second reaction kettle to 200° C., and maintain it at 200° C. for 1 hour, while continuously stirring the mixture in the second reaction kettle;

[0042] S63. After 1 hour, continue to increase the temperature in the second reactor to 255 degrees Celsius and heat for 20 minutes. After 20 minutes, increase the temperature in the second reactor to 320 degrees Celsius and continue for 3 hours to form a PEEK grafted polymerization product.

[0043] The step S7 also includes a sizing process of a sizing agent, which is characterized by comprising the following steps: S71, immersing the fiber bundle to be sized in an aqueous sizing agent for a soaking time of T;

[0044] S72, after a period of time T, taking out the fiber bundle in the aqueous sizing agent, and squeezing to remove most of the excess water and solution;

[0045] S73, drying the fiber bundle to further remove excess water and solution, and completing sizing of the fiber bundle.

[0046] The present application also provides a sizing agent produced based on the preparation process of the above-mentioned fiber surface high-temperature resistant thermoplastic aqueous solution sizing agent, wherein the sizing agent is composed of a prepolymer of polyetheretherketone (PEEK), a hydrophilic and lipophilic active agent and water.

[0047] Preferably, in the sizing agent, the hydrophilic and lipophilic active agents account for 55% of the total mass, the PEEK prepolymer accounts for 25% of the total mass, and water accounts for 20% of the total mass.

[0048] Since polyetheretherketone (PEEK) is a typical water-insoluble material, any solvent except concentrated sulfuric acid cannot dissolve PEEK. In this application, the prepolymer of PEEK is used as the main component of the sizing agent. The prepolymer of PEEK is an intermediate product in the polymerization reaction of PEEK. Since the molecular chain is short and contains active end groups, it has good solubility and is easy to process. It can be better mixed with other additives or reinforcing materials. A surfactant for increasing its hydrophilicity and lipophilicity is added to the prepolymer of PEEK to form a PEEK grafted polymerization product, so as to improve the prepolymer of PEEK. The emulsification, dispersion and wetting properties of the body in an aqueous medium are improved, and the grafted polymerization product of PEEK is ground into nano-scale fine powder so that it can be evenly dispersed in a deionized water solution to form an evenly dispersed aqueous solution, so that the finished sizing agent has good water solubility, can reduce the surface tension of the sizing agent solution, so that it can better spread and penetrate on the fiber surface, and the PEEK has excellent high temperature resistance, mechanical properties and chemical stability. As the main film-forming substance of the sizing agent, it can form a continuous and stable protective film on the fiber surface, thereby improving the heat resistance and wear resistance of the fiber.

[0049] Furthermore, in order to produce PEEK prepolymer to obtain the raw materials for the reaction, the PEEK prepolymer is usually prepared by a nucleophilic substitution reaction. The raw materials are mainly 4,4'-difluorobenzophenone (DFBP), hydroquinone (HQ) and potassium carbonate (K2CO3), and diphenyl sulfone (DPS) is used as the main reaction solvent. The molar ratio of DFBP to HQ is 1:1, which is conducive to the formation of a relatively regular linear molecular structure, so that the polymerization degree of the finished product is high, the molecular weight of the polymer is large, and the final prepolymer has certain lipophilicity and hydrophilicity. At the same time, in the production process, by The temperature should be set between 180-300℃. If the temperature is less than 180℃ during the reaction, the rate of nucleophilic substitution reaction or polycondensation reaction between DFBP and HQ is significantly lower, and the reaction takes a long time to reach a certain conversion rate. When the temperature is greater than 300℃, although the reaction rate may be further accelerated, it may also cause some side reactions, such as polymer degradation and cross-linking, which will affect the quality and performance of the prepolymer and even cause the reaction to run out of control. By setting the reaction temperature between 180-300℃, the collision frequency between the raw material molecules is increased, the reaction rate is accelerated, and it is conducive to the formation of the prepolymer. At this time, the number of activated molecules in the reaction system increases, the effective collision probability increases, the reaction can proceed faster, and the production efficiency is improved. In addition, the raw materials are continuously stirred during the reaction, which can further increase the reaction rate.

[0050] At the same time, in order to make the finished product have better water solubility, by adding hydrophilic and lipophilic active agents into the PEEK prepolymer, the PEEK material can have better surface activity and its dispersibility in different phases (such as water phase and oil phase), and the hydrophilic and lipophilic active agent is one of monoglyceride, polyoxyethylene fatty alcohol ether, polyoxyethylene-polyoxypropylene copolymer, sodium sulfate of fatty alcohol polyoxyethylene ether, sodium sulfate of alkylphenol polyoxyethylene ether, and dodecyl dimethyl hydroxyethyl ammonium chloride, which can form a chemical bond between the hydrophilic and lipophilic active agent and the PEEK prepolymer. Compared with simple physical mixing, this chemical bonding method can make the material performance more stable. For example, in the long-term use process, the chemically bonded structure is not easy to phase separate. , thereby ensuring the consistency of material properties, and after PEEK is grafted with hydrophilic groups to form a PEEK grafted polymer product, the finished product is ground into nano-scale fine powder, so that it can be more evenly dispersed in water, further improving the uniformity of the solution. At the same time, in the process of grafting, the grafting temperature is set to 180-255°C and the cumulative heating is 2h20min, which can increase the collision frequency between the raw material molecules, greatly improve the effective collision probability, and achieve a higher conversion rate in a short time. Heating at a processing temperature of 320°C for 3h can enhance the interaction between the PEEK prepolymer and the hydrophilic and lipophilic surfactant, promote the mixing and compatibility of the two, and make the polymer product form a more uniform phase structure, improve the overall performance of the product, and have a good processing effect and high processing efficiency.

[0051] In addition, in order to improve the surface activity and dispersibility of the sizing agent as an aqueous solution, so as to improve the overall emulsification performance in an aqueous medium, it is necessary to increase the proportion of hydrophilic and lipophilic surfactants. Generally speaking, the hydrophilic and lipophilic surfactants account for 55% of the total mass, the PEEK prepolymer accounts for 25% of the total mass, and water accounts for 20% of the total mass. This can effectively reduce the surface tension of the product at the oil-water interface, play an emulsifying and dispersing role, and has good affinity with the limiting surface, and can form a suitable sizing solution.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Common changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A process for preparing a high temperature resistant thermoplastic aqueous solution sizing agent for fiber surface, characterized in that: The following steps are involved: S1. Raw material preparation: The staff prepares the main raw materials required for the nucleophilic substitution reaction, which are 4,4'-difluorobenzophenone (DFBP), hydroquinone (HQ) and potassium carbonate (K2CO3), and diphenyl sulfone (DPS) is used as the main reaction solvent; S2. Obtaining the reaction ratio: preparing the molar amounts of DFBP and HQ in a molar ratio of 1:1, and calculating the molar amount of K2CO3 based on the molar amounts of DFBP and HQ, so that K2CO3:DFBP:HQ is 2.5:1:1, and calculating the mass of DPS based on the total mass of DFBP and HQ, so that the total mass of DFBP and HQ accounts for 25% of the mass of DPS; S3, reaction mixing: pour the raw materials into the reactor for mixing, set the reaction temperature between 180-300° C., and continuously stir the raw materials during the mixing process. The reaction time is 20 hours to obtain a mixture; S4. Preparation of PEEK prepolymer: After the reaction is completed, the mixture is cooled to room temperature, and dilute hydrochloric acid is poured into the mixture to precipitate the polymer to obtain the prepolymer; S5. PEEK prepolymer extraction: filtering the mixture to obtain a polymer, and repeatedly washing with deionized water and an organic solvent to remove the raw material solvent and impurities to obtain a PEEK prepolymer; S6, secondary polymerization: placing the PEEK prepolymer prepared in step S5 into a second reactor, and adding a hydrophilic and lipophilic surfactant into the reactor, so that the active functional groups of the hydrophilic and lipophilic surfactant react chemically with the PEEK prepolymer, thereby grafting the hydrophilic and lipophilic surfactant onto the PEEK polymer to form a PEEK grafted polymer product; S7, aqueous solution mixing: grinding the PEEK grafted polymer product obtained in step S6 into nanometer scale, and adding water to form an aqueous solution sizing agent.

2. The process for preparing a high temperature resistant thermoplastic aqueous solution sizing agent for fiber surface according to claim 1, characterized in that: The hydrophilic and lipophilic active agent in step S6 is one of monoglyceride of fatty acid, polyoxyethylene fatty alcohol ether, polyoxyethylene-polyoxypropylene copolymer, sodium sulfate of fatty alcohol polyoxyethylene ether, sodium sulfate of alkylphenol polyoxyethylene ether, and dodecyl dimethyl hydroxyethyl ammonium chloride.

3. The process for preparing a high temperature resistant thermoplastic aqueous solution sizing agent for fiber surface according to claim 1, characterized in that: The step S6 also includes a grafting method of a PEEK polymer, comprising the following steps: S61, raising the temperature of the second reaction kettle to 180° C., and maintaining the temperature at 180° C. for 1 hour, while continuously stirring the mixture in the second reaction kettle; S62, after 1 hour, continue to increase the temperature in the second reactor to 200° C., and maintain it at 200° C. for 1 hour, while continuously stirring the mixture in the second reactor; S63. After 1 hour, continue to increase the temperature in the second reactor to 255 degrees Celsius and heat for 20 minutes. After 20 minutes, increase the temperature in the second reactor to 320 degrees Celsius and continue for 3 hours to form a PEEK grafted polymerization product.

4. The process for preparing a high temperature resistant thermoplastic aqueous solution sizing agent for fiber surface according to claim 1, characterized in that: The step S7 also includes a sizing process of a sizing agent, which is characterized by comprising the following steps: S71, immersing the fiber bundle to be sized in an aqueous sizing agent for a soaking time of T; S72, after a period of time T, taking out the fiber bundle in the aqueous sizing agent, and squeezing to remove most of the excess water and solution; S73, drying the fiber bundle to further remove excess water and solution, and completing sizing of the fiber bundle.

5. A sizing agent suitable for the preparation process of the fiber surface high temperature resistant thermoplastic aqueous solution sizing agent according to claims 1 to 4, characterized in that: The sizing agent consists of a prepolymer of polyetheretherketone (PEEK), a hydrophilic and lipophilic active agent and water.

6. The sizing agent produced by the preparation process of a high temperature resistant thermoplastic aqueous solution sizing agent for fiber surface according to claim 5, characterized in that: In the sizing agent, the hydrophilic and lipophilic active agent accounts for 55% of the total mass, the PEEK prepolymer accounts for 25% of the total mass, and water accounts for 20% of the total mass.

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