High-strength high-temperature-resistant composite plastic-burned plate and preparation process thereof

Abstract

The application relates to a high-strength high-temperature-resistant composite plastic sintering plate and a preparation process thereof, and belongs to the technical field of plastic sintering plates. The high-strength high-temperature-resistant composite plastic sintering plate comprises a plastic sintering plate base body and a protective layer on the surface of the base body; the plastic sintering plate base body is formed into a porous structure through sintering, and the plastic sintering plate base body comprises the following raw materials in parts by weight: 100 parts of base body resin, 10-30 parts of reinforcing fibers, 0.5-3 parts of a coupling agent and 1-2 parts of a lubricant; the protective layer is a double-layer structure, comprising a transition layer combined with the surface of the base body and a surface layer located at the outermost layer; the material of the transition layer comprises a thermoplastic resin and polytetrafluoroethylene, and the material of the functional surface layer comprises polytetrafluoroethylene and a high-temperature-resistant modifier; the prepared plastic sintering plate has excellent high-temperature resistance and strength.

Description

Technical Field

[0001] This invention belongs to the field of sintered plastic plate technology, and relates to a high-strength, high-temperature resistant composite sintered plastic plate and its preparation process. Background Technology

[0002] Sintered plastic filtration plates are widely used in flue gas dust removal in industries such as steel, chemicals, and cement due to their excellent filtration performance and chemical corrosion resistance. However, traditional sintered plastic filtration plates are prone to problems such as substrate cracking, surface coating peeling, and decreased filtration efficiency under harsh working conditions such as high temperature, high humidity, strong corrosion, or strong impact, resulting in a shortened service life. Existing technologies mainly improve performance through substrate material modification or surface coating, but these technologies suffer from technical bottlenecks such as uneven dispersion of modified components and insufficient membrane adhesion.

[0003] Therefore, developing a composite sintered plastic plate that combines high strength, high temperature resistance, and excellent interfacial bonding has significant industrial value. Summary of the Invention

[0004] The purpose of this invention is to provide a high-strength, high-temperature resistant composite sintered plastic plate and its preparation process. The prepared sintered plastic plate has excellent high-temperature resistance and strength.

[0005] The objective of this invention can be achieved through the following technical solutions: A high-strength, high-temperature resistant composite sintered plate includes a sintered plate matrix and a protective layer on the surface of the matrix; the sintered plate matrix is ​​sintered to form a porous structure, and the sintered plate matrix includes the following raw materials in parts by weight: 100 parts matrix resin, 10-30 parts reinforcing fiber, 0.5-3 parts coupling agent, and 1-2 parts lubricant; The protective layer has a double-layer structure, including a transition layer bonded to the surface of the substrate and an outermost surface layer; the transition layer is made of thermoplastic resin and polytetrafluoroethylene, and the surface layer is made of polytetrafluoroethylene and a high-temperature modifier.

[0006] As a preferred embodiment of the present invention, the preparation process of the reinforcing fiber is as follows: Glass fibers were immersed in an ethanol aqueous solution containing 2-5% KH-550, ultrasonically treated for 30 min, and dried at 80℃ for 2 h to obtain aminated fibers. Aminated fibers were dispersed in NMP, and pyromellitic dianhydride and 4,4'-diaminodiphenyl ether were added in a molar ratio of 1:1. Tetrabutyl titanate, water, and glacial acetic acid were also added. The mixture was stirred for 30 min to obtain a homogeneous solution, wherein the content of tetrabutyl titanate was 10-20% of the mass of pyromellitic dianhydride. The solution was treated at 60°C for 15-25 min under microwave assistance of 300 W, and then heated to 200°C and held for 2 h to obtain the reinforcing fibers.

[0007] As a preferred embodiment of the present invention, the preparation process of the high-temperature resistant modifier is as follows: S31. Graphene oxide was dispersed in a 10 mM pH Tris-HCl buffer solution and sonicated for 1 h to form a dispersion with a concentration of 1 mg / mL. Dopamine hydrochloride with a mass ratio of 1:2 to graphene oxide was added and stirred at room temperature for 18-24 h. After centrifugation, washing with water, and vacuum drying at 60 °C, pretreated graphene oxide was obtained. S32. Under nitrogen protection, pyromellitic dianhydride and tris(4-aminophenyl)amine in a molar ratio of 1:1 were added to anhydrous N-methylpyrrolidone and stirred at room temperature for 4 h. Then, 15% by volume of toluene of N-methylpyrrolidone was added, and the mixture was heated to 160 °C and stirred under reflux for 6 h to obtain mixture A. S33. Disperse pretreated graphene oxide in N-methylpyrrolidone, sonicate for 30 min, add mixture A and p-toluenesulfonic acid, stir for 8 h under nitrogen protection at 80℃, filter, wash, and vacuum dry at 60℃ to obtain the high-temperature resistant modifier.

[0008] As a preferred embodiment of the present invention, the matrix resin is one of polyethylene, polyvinylidene fluoride, and polyphenylene sulfide.

[0009] As a preferred embodiment of the present invention, the thermoplastic resin is polyetheretherketone or polyvinylidene fluoride.

[0010] As a preferred embodiment of the present invention, the mass fraction of polytetrafluoroethylene in the transition layer is 30-40%.

[0011] As a preferred embodiment of the present invention, the high-temperature resistant modifier has a mass fraction of 5-15% in the surface layer.

[0012] As a preferred embodiment of the present invention, the molar ratio of tetrabutyl titanate, water and glacial acetic acid is (1~1.2):4:0.05.

[0013] As a preferred embodiment of the present invention, the mass ratio of the pretreated graphene oxide, mixture A and p-toluenesulfonic acid is 1:0.5:(0.1~0.3).

[0014] A process for preparing a high-strength, high-temperature resistant composite sintered plastic plate includes the following steps: S1, Mixing of matrix materials: The matrix resin, reinforcing fiber, coupling agent and lubricant are mixed according to the weight parts, and stirred at 1000 r / min for 15 to 30 min at 40 to 60°C to obtain the mixture; S2, Compression molding and sintering: The mixture is filled into a sintered plastic plate mold and sintered at 200~260℃ and 5~15MPa for 60~120min. Then it is cooled and demolded to obtain a porous sintered plastic plate matrix. S3. Substrate surface pretreatment: The surface of the obtained porous sintered plastic plate substrate was polished with a 500-grit grinding head and a 2000-grit grinding head in sequence, and then the surface dust was removed by nitrogen blowing. S4, Transition layer coating: Thermoplastic resin and polytetrafluoroethylene particles are dispersed in a solvent to prepare a first coating liquid, which is then coated onto the pretreated substrate surface by spraying or dipping, and a transition layer is formed after drying. S5, Topcoat coating: A second coating liquid is prepared by dispersing polytetrafluoroethylene and a high-temperature resistant modifier in a solvent, which is then coated onto the surface of the transition layer and dried to form a top layer. S6. Heat treatment: The coated sintered plastic plate is heat-treated at 280~320℃ for 30~60 minutes and then naturally cooled to room temperature to obtain the high-strength, high-temperature resistant composite sintered plastic plate.

[0015] In the preparation of reinforcing fibers, this invention introduces tetrabutyl titanate as a titanium source, and combines microwave-assisted heating and in-situ polymerization / hydrolysis simultaneous reaction to form a modified glass fiber coated with a polyimide / titanium dioxide organic-inorganic hybrid coating.

[0016] On the one hand, by introducing polyimide onto the surface of glass fibers, the good compatibility between polyimide and the sintered plate matrix is ​​utilized to improve the bonding force between the fibers and the matrix. Simultaneously, it protects the fibers from performance degradation during sintering or high-temperature service of the sintered plate, thereby improving the overall mechanical properties of the composite material. On the other hand, TiO2 generated from the hydrolysis of tetrabutyl titanate grows in situ within the polyimide matrix, acting as rigid particles to further enhance hardness. When the reinforcing fibers are combined with the sintered plate matrix resin, the TiO2 nanoparticles embed into the matrix resin, forming a nanoscale mechanical interlock. This dual interfacial reinforcement mechanism of chemical bonding (PI and fiber) and physical anchoring (TiO2 and matrix) enhances the interfacial bonding strength.

[0017] The preparation process utilizes microwave assistance to achieve rapid and uniform modification. Microwave heating has volume heating characteristics, which can rapidly and uniformly raise the temperature of the reaction system on the fiber surface, shorten the reaction time, and at the same time promote the uniform dispersion of TiO2 particles in the polyimide matrix, resulting in a stronger bond with the fiber.

[0018] The protective layer on the substrate surface consists of a transition layer and a surface layer. The transition layer can improve the bonding force between the substrate and the surface layer, providing physical anchoring and stress buffering, while the surface layer helps to improve high temperature resistance. Together, they form a composite protective layer with compositional gradient and complementary functions.

[0019] A high-temperature resistant modifier was added to the surface layer. Using graphene oxide as the base, the nano-reinforcing effect of graphene oxide was combined with the high-temperature resistant properties of polyimide through polydopamine and hyperbranching treatment. At the same time, the structure of the hyperbranched polymer was used to improve dispersibility.

[0020] First, dopamine oxidation self-polymerization is used to improve its compatibility and interfacial bonding. Then, pyromellitic dianhydride and tris(4-aminophenyl)amine undergo condensation polymerization to generate hyperbranched polyamic acid with amino end groups. After imidization, amino-terminated hyperbranched polyimide is obtained. Hyperbranched polyimide is grafted onto the graphene surface. When the material is under stress, it can effectively transfer the stress to the high-strength graphene core, achieving nanoscale reinforcement. At the same time, the chemical structure and interfacial bonding ability of the modifier remain stable during the high-temperature sintering and high-temperature service of the sintered plate. The reinforcement effect will not be lost due to the decomposition of the modifier itself, which significantly improves the surface layer's hardness, compressive strength, and high-temperature resistance.

[0021] The beneficial effects of this invention are: The composite sintered plastic plate prepared by this invention consists of a sintered plastic plate matrix and a protective layer on the surface of the matrix, wherein reinforcing fibers are added to the matrix to improve overall performance. Through the modification of the matrix reinforcing fibers, the addition of a high-temperature resistant modifier to the surface layer, and the synergistic construction of the double protective layer, the prepared composite sintered plastic plate exhibits excellent strength and high-temperature resistance. Detailed Implementation

[0022] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.

[0023] It should be noted that in the following examples, the polyethylene used is ultra-high molecular weight polyethylene with a molecular weight of 3 million; polyetheretherketone: Shanghai Mairui Biochemical Technology Co., Ltd., item number: M69225; glass fiber: Wuhan Jiyesheng Chemical Co., Ltd., item number: W01193; pyromellitic dianhydride: Tianjin Zhongtai Materials Technology Co., Ltd., item number: 064; 4,4'-diaminodiphenyl ether: Tianjin Zhongtai Materials Technology Co., Ltd., item number: 101-80-4; Unless otherwise specified, the present invention does not specifically limit the source of other raw materials used. Commercially available products or products prepared by conventional preparation methods that are well known to those skilled in the art can be used. Experimental methods that do not specify specific conditions are all conventional methods and conditions well known in the art.

[0024] Example 1 Preparation of reinforcing fibers: Glass fibers were immersed in an ethanol solution containing 2% KH-550, ultrasonically treated for 30 min, and dried at 80℃ for 2 h to obtain aminated fibers. Aminated fibers were dispersed in NMP, and pyromellitic dianhydride and 4,4'-diaminodiphenyl ether were added in a molar ratio of 1:1. Simultaneously, tetrabutyl titanate, water, and glacial acetic acid were added in a molar ratio of 1.1:4:0.05. The mixture was stirred for 30 min to obtain a homogeneous solution, wherein the tetrabutyl titanate content was 5% of the mass of pyromellitic dianhydride. The solution was treated at 60 °C for 20 min under 300 W microwave assistance, and then heated to 200 °C and held for 2 h to obtain the reinforcing fibers.

[0025] Preparation of high-temperature resistant modifier: S31. Graphene oxide was dispersed in a 10 mM pH Tris-HCl buffer solution and sonicated for 1 h to form a dispersion with a concentration of 1 mg / mL. Dopamine hydrochloride with a mass ratio of 1:2 to graphene oxide was added and stirred at room temperature for 20 h. After centrifugation, washing with water, and vacuum drying at 60 °C, pretreated graphene oxide was obtained. S32. Under nitrogen protection, pyromellitic dianhydride and tris(4-aminophenyl)amine in a molar ratio of 1:1 were added to anhydrous N-methylpyrrolidone and stirred at room temperature for 4 h. Then, 15% by volume of toluene of N-methylpyrrolidone was added, and the mixture was heated to 160 °C and stirred under reflux for 6 h to obtain mixture A. S33. Disperse pretreated graphene oxide in N-methylpyrrolidone, sonicate for 30 min, add mixture A and p-toluenesulfonic acid, stir for 8 h under nitrogen protection at 80℃, filter, wash, and vacuum dry at 60℃ to obtain the high-temperature resistant modifier. The mass ratio of pretreated graphene oxide, mixture A and p-toluenesulfonic acid is 1:0.5:0.2.

[0026] Preparation of composite sintered plastic plates: S1, Mixing of matrix materials: According to the weight proportions, 100 parts of polyethylene, 20 parts of reinforcing fiber, 2 parts of titanate coupling agent and 1.5 parts of calcium stearate are mixed and stirred at 1000 r / min for 20 min at 50°C to obtain the mixture. S2, Compression molding and sintering: The mixture is filled into a sintered plastic plate mold and sintered at 240℃ and 10MPa for 90 minutes. Then it is cooled and demolded to obtain a porous sintered plastic plate matrix. S3. Substrate surface pretreatment: The surface of the obtained porous sintered plastic plate substrate was polished with a 500-grit grinding head and a 2000-grit grinding head in sequence, and then the surface dust was removed by nitrogen blowing. S4, Transition layer coating: The first coating liquid is prepared by mixing 35% polyetheretherketone, 32% polytetrafluoroethylene particles and 33% NMP by mass percentage. It is then coated on the substrate surface by electrostatic spraying at a spraying voltage of 50kV, a spraying distance of 200mm, and a coating thickness of 40μm. After drying at 100℃ for 30min, a transition layer is formed. S5, Topcoat coating: The coating liquid is prepared by mixing 55% polytetrafluoroethylene, 10% high-temperature modifier and 35% NMP by mass percentage. It is then applied to the surface of the transition layer by electrostatic spraying with a spraying voltage of 50kV, a spraying distance of 200mm and a coating thickness of 30μm. After drying at 100℃ for 20min, the top layer is formed. S6. Heat treatment: The coated sintered plastic plate was heat-treated at 300℃ for 40 minutes and then naturally cooled to room temperature to obtain the high-strength, high-temperature resistant composite sintered plastic plate.

[0027] Example 2 Preparation of reinforcing fibers: Glass fibers were immersed in an ethanol solution containing 2% KH-550, ultrasonically treated for 30 min, and dried at 80℃ for 2 h to obtain aminated fibers. Aminated fibers were dispersed in NMP, and pyromellitic dianhydride and 4,4'-diaminodiphenyl ether were added in a molar ratio of 1:1. Simultaneously, tetrabutyl titanate, water, and glacial acetic acid were added in a molar ratio of 1:4:0.05. The mixture was stirred for 30 min to obtain a homogeneous solution, wherein the content of tetrabutyl titanate was 10% of the mass of pyromellitic dianhydride. The solution was treated at 60 °C for 20 min under microwave assistance of 300 W, and then heated to 200 °C and held for 2 h to obtain the reinforcing fibers.

[0028] Preparation of high-temperature resistant modifier: S31. Graphene oxide was dispersed in a 10 mM pH Tris-HCl buffer solution and sonicated for 1 h to form a dispersion with a concentration of 1 mg / mL. Dopamine hydrochloride with a mass ratio of 1:2 to graphene oxide was added and stirred at room temperature for 18 h. After centrifugation, washing with water, and vacuum drying at 60 °C, pretreated graphene oxide was obtained. S32. Under nitrogen protection, pyromellitic dianhydride and tris(4-aminophenyl)amine in a molar ratio of 1:1 were added to anhydrous N-methylpyrrolidone and stirred at room temperature for 4 h. Then, 15% by volume of toluene of N-methylpyrrolidone was added, and the mixture was heated to 160 °C and stirred under reflux for 6 h to obtain mixture A. S33. Disperse pretreated graphene oxide in N-methylpyrrolidone, sonicate for 30 min, add mixture A and p-toluenesulfonic acid, stir for 8 h under nitrogen protection at 80℃, filter, wash, and vacuum dry at 60℃ to obtain the high-temperature resistant modifier. The mass ratio of pretreated graphene oxide, mixture A and p-toluenesulfonic acid is 1:0.5:0.1.

[0029] Preparation of composite sintered plastic plates: S1, Mixing of matrix materials: Mix 100 parts polyethylene, 10 parts reinforcing fiber, 0.5 parts titanate coupling agent and 1 part calcium stearate by weight, and stir at 1000 r / min for 15 min at 40°C to obtain a mixture. S2, Compression molding and sintering: The mixture is filled into a sintered plastic plate mold and sintered at 200℃ and 5MPa for 60 minutes. Then it is cooled and demolded to obtain a porous sintered plastic plate matrix. S3. Substrate surface pretreatment: The surface of the obtained porous sintered plastic plate substrate was polished with a 500-grit grinding head and a 2000-grit grinding head in sequence, and then the surface dust was removed by nitrogen blowing. S4, Transition layer coating: The first coating liquid is prepared by mixing 30% polyetheretherketone, 30% polytetrafluoroethylene particles and 40% NMP by mass percentage. It is then coated on the substrate surface by electrostatic spraying at a spraying voltage of 50kV, a spraying distance of 200mm, and a coating thickness of 40μm. After drying at 100℃ for 30min, a transition layer is formed. S5, Topcoat coating: The second coating liquid is prepared by mixing 50% polytetrafluoroethylene, 5% high-temperature modifier and 45% NMP by mass percentage. It is then coated on the surface of the transition layer by electrostatic spraying with a spraying voltage of 50kV, a spraying distance of 200mm and a coating thickness of 30μm. After drying at 100℃ for 20min, the top layer is formed. S6. Heat treatment: The coated sintered plastic plate was heat-treated at 280°C for 30 minutes and then naturally cooled to room temperature to obtain the high-strength, high-temperature resistant composite sintered plastic plate.

[0030] Example 3 Preparation of reinforcing fibers: Glass fibers were immersed in an ethanol solution containing 2% KH-550, ultrasonically treated for 30 min, and dried at 80℃ for 2 h to obtain aminated fibers. Aminated fibers were dispersed in NMP, and pyromellitic dianhydride and 4,4'-diaminodiphenyl ether were added in a molar ratio of 1:1. Simultaneously, tetrabutyl titanate, water, and glacial acetic acid were added in a molar ratio of 1.2:4:0.05. The mixture was stirred for 30 min to obtain a homogeneous solution, wherein the tetrabutyl titanate content was 20% of the mass of pyromellitic dianhydride. The solution was treated at 60 °C for 25 min under 300 W microwave assistance, and then heated to 200 °C and held for 2 h to obtain the reinforcing fibers.

[0031] Preparation of high-temperature resistant modifier: S31. Graphene oxide was dispersed in a 10 mM pH Tris-HCl buffer solution and sonicated for 1 h to form a dispersion with a concentration of 1 mg / mL. Dopamine hydrochloride with a mass ratio of 1:2 to graphene oxide was added and stirred at room temperature for 24 h. After centrifugation, washing with water, and vacuum drying at 60 °C, pretreated graphene oxide was obtained. S32. Under nitrogen protection, pyromellitic dianhydride and tris(4-aminophenyl)amine in a molar ratio of 1:1 were added to anhydrous N-methylpyrrolidone and stirred at room temperature for 4 h. Then, 15% by volume of toluene of N-methylpyrrolidone was added, and the mixture was heated to 160 °C and stirred under reflux for 6 h to obtain mixture A. S33. Disperse pretreated graphene oxide in N-methylpyrrolidone, sonicate for 30 min, add mixture A and p-toluenesulfonic acid, stir for 8 h under nitrogen protection at 80℃, filter, wash, and vacuum dry at 60℃ to obtain the high-temperature resistant modifier. The mass ratio of pretreated graphene oxide, mixture A and p-toluenesulfonic acid is 1:0.5:0.3.

[0032] Preparation of composite sintered plastic plates: S1, Mixing of matrix materials: According to the weight proportions, 100 parts of polyethylene, 30 parts of reinforcing fiber, 3 parts of titanate coupling agent and 2 parts of calcium stearate are mixed and stirred at 1000 r / min for 30 min at 60°C to obtain the mixture. S2, Compression molding and sintering: The mixture is filled into a sintered plastic plate mold and sintered at 260℃ and 15MPa for 120 minutes. Then it is cooled and demolded to obtain a porous sintered plastic plate matrix. S3. Substrate surface pretreatment: The surface of the obtained porous sintered plastic plate substrate was polished with a 500-grit grinding head and a 2000-grit grinding head in sequence, and then the surface dust was removed by nitrogen blowing. S4, Transition layer coating: The first coating liquid is prepared by mixing 45% polyetheretherketone, 40% polytetrafluoroethylene particles and 15% NMP by mass percentage. It is then coated on the substrate surface by electrostatic spraying at a spraying voltage of 50kV, a spraying distance of 200mm, and a coating thickness of 40μm. After drying at 100℃ for 30min, a transition layer is formed. S5, Topcoat coating: By mass percentage, 65% polytetrafluoroethylene, 15% high-temperature modifier and 20% NMP are mixed to obtain a coating liquid, which is then applied to the surface of the transition layer by electrostatic spraying at a spraying voltage of 50kV, a spraying distance of 200mm and a coating thickness of 30μm. After drying at 100℃ for 20min, a top layer is formed. S6. Heat treatment: The coated sintered plastic plate was heat-treated at 320°C for 60 minutes and then naturally cooled to room temperature to obtain the high-strength, high-temperature resistant composite sintered plastic plate.

[0033] Comparative Example 1 This is basically the same as Example 1, except that the glass fiber in this comparative example has not undergone any modification treatment.

[0034] Comparative Example 2 It is basically the same as Example 1, except that step S31 was not performed in the preparation process of the high temperature resistant modifier in this comparative example.

[0035] Comparative Example 3 This is basically the same as Example 1, except that the high-temperature modifier in this comparative example is graphene oxide that has not undergone any modification treatment.

[0036] Comparative Example 4 It is basically the same as Example 1, except that step S4 is not performed in this comparative example.

[0037] Performance testing: 1. Tensile strength: Refer to GB / T 1040-2006, the specimen is dumbbell-shaped, and the tensile speed is 50 mm / min; 2. Place a sample measuring 120*100*80mm in a heating furnace and heat it at a rate of 2℃ / min under an environment of 0.45MPa. Observe the temperature at which the sintered plate deforms. 3. Adhesion: Referring to GB / T 9286-2021, the test results are shown in the table below: Based on the above data, it can be seen that the composite sintered plate prepared by the present invention has excellent strength and high temperature resistance.

[0038] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A high-strength, high-temperature resistant composite sintered steel plate, characterized in that, It includes a sintered plate substrate and a protective layer on the surface of the substrate; the sintered plate substrate is sintered to form a porous structure, and the sintered plate substrate includes the following raw materials in parts by weight: 100 parts of matrix resin, 10-30 parts of reinforcing fiber, 0.5-3 parts of coupling agent, and 1-2 parts of lubricant; The protective layer has a double-layer structure, including a transition layer bonded to the surface of the substrate and an outermost surface layer; the transition layer is made of thermoplastic resin and polytetrafluoroethylene, and the surface layer is made of polytetrafluoroethylene and a high-temperature modifier.

2. The high-strength, high-temperature resistant composite sintered steel plate according to claim 1, characterized in that, The preparation process of the reinforcing fiber is as follows: Glass fibers were immersed in an ethanol aqueous solution containing 2-5% KH-550, ultrasonically treated for 30 min, and dried to obtain aminated fibers. Aminated fibers were dispersed in NMP, and pyromellitic dianhydride and 4,4'-diaminodiphenyl ether were added in a molar ratio of 1:

1. Tetrabutyl titanate, water, and glacial acetic acid were also added. The mixture was stirred for 30 min to obtain a homogeneous solution, wherein the content of tetrabutyl titanate was 10-20% of the mass of pyromellitic dianhydride. The solution was treated at 60°C for 15-25 min under microwave assistance of 300 W, and then heated to 200°C and held for 2 h to obtain the reinforcing fibers.

3. The high-strength, high-temperature resistant composite sintered steel plate according to claim 1, characterized in that, The preparation process of the high-temperature resistant modifier is as follows: S31. Graphene oxide is dispersed in a 10 mM pH Tris-HCl buffer solution and sonicated for 1 h to form a dispersion with a concentration of 1 mg / mL. Dopamine hydrochloride with a mass ratio of 1:2 to graphene oxide is added and stirred at room temperature for 18-24 h. After centrifugation, washing with water and drying, pretreated graphene oxide is obtained. S32. Under nitrogen protection, pyromellitic dianhydride and tris(4-aminophenyl)amine in a molar ratio of 1:1 were added to anhydrous N-methylpyrrolidone and stirred at room temperature for 4 h. Then, 15% by volume of toluene of N-methylpyrrolidone was added and stirred for 6 h to obtain mixture A. S33. Disperse the pretreated graphene oxide in NMP, sonicate for 30 min, add mixture A and p-toluenesulfonic acid, stir for 8 h under nitrogen protection at 80℃, filter, wash and dry to obtain the high temperature resistant modifier.

4. The high-strength, high-temperature resistant composite sintered steel plate according to claim 1, characterized in that, The matrix resin is one of polyethylene, polyvinylidene fluoride, and polyphenylene sulfide.

5. The high-strength, high-temperature resistant composite sintered steel plate according to claim 1, characterized in that, The thermoplastic resin is polyetheretherketone or polyvinylidene fluoride.

6. The high-strength, high-temperature resistant composite sintered steel plate according to claim 1, characterized in that, The mass fraction of polytetrafluoroethylene in the transition layer is 30-40%.

7. The high-strength, high-temperature resistant composite sintered steel plate according to claim 1, characterized in that, The high-temperature resistant modifier has a mass fraction of 5-15% in the surface layer.

8. The high-strength, high-temperature resistant composite sintered steel plate according to claim 2, characterized in that, The molar ratio of tetrabutyl titanate, water and glacial acetic acid is (1~1.2):4:0.

05.

9. The high-strength, high-temperature resistant composite sintered steel plate according to claim 3, characterized in that, The mass ratio of the pretreated graphene oxide, mixture A and p-toluenesulfonic acid is 1:0.5:(0.1~0.3).

10. A preparation process for a high-strength, high-temperature resistant composite sintered steel plate as described in any one of claims 1-9, characterized in that, Includes the following steps: S1, Mixing of matrix materials: The matrix resin, reinforcing fiber, coupling agent and lubricant are mixed according to the weight parts, and stirred at 1000 r / min for 15 to 30 min at 40 to 60°C to obtain the mixture; S2, Compression molding and sintering: The mixture is filled into a sintered plastic plate mold and sintered at 200~260℃ and 5~15MPa for 60~120min. Then it is cooled and demolded to obtain a porous sintered plastic plate matrix. S3. Substrate surface pretreatment: The surface of the obtained porous sintered plastic plate substrate was polished with a 500-grit grinding head and a 2000-grit grinding head in sequence, and then the surface dust was removed by nitrogen blowing. S4, Transition layer coating: Thermoplastic resin and polytetrafluoroethylene particles are dispersed in a solvent to prepare a first coating liquid, which is then coated onto the pretreated substrate surface by spraying or dipping, and a transition layer is formed after drying. S5, Topcoat coating: A second coating liquid is prepared by dispersing polytetrafluoroethylene and a high-temperature resistant modifier in a solvent, which is then coated onto the surface of the transition layer and dried to form a top layer. S6. Heat treatment: The coated sintered plastic plate is heat-treated at 280~320℃ for 30~60 minutes and then naturally cooled to room temperature to obtain the high-strength, high-temperature resistant composite sintered plastic plate.

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