A self-lubricating and wear-resistant polyphenylene sulfide-based composite material and its preparation method

Abstract

The present invention relates to a self-lubricating, wear-resistant polyphenylene sulfide-based composite material, comprising the following raw materials in parts by weight: 75-90 parts of interface-modified polyphenylene sulfide particles, 5-10 parts of polytetrafluoroethylene particles, 10-20 parts of reinforcing fibers, and 0.2-1 part of a lubricant. The interface-modified polyphenylene sulfide particles are obtained by polymerizing dopamine on the surface of the polyphenylene sulfide particles to form polyphenylene sulfide@polydopamine (PPS@PDA) microspheres, which are then coated with a benzimidazole-based fluorinated polyimide gel and freeze-dried to form a composite interface. The dopamine content is 1-3% by weight of the polyphenylene sulfide particles, and the benzimidazole-based fluorinated polyimide gel content is 20-30% by weight of the PPS@PDA microspheres. The polyphenylene sulfide-based composite material prepared by the present invention has excellent wear resistance and mechanical strength while maintaining a low friction coefficient.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and particularly relates to a self-lubricating and wear-resistant polyphenylene sulfide-based composite material and a preparation method thereof. Background Art

[0002] Polyphenylene sulfide (PPS) is a semi-crystalline engineering plastic with excellent comprehensive performance. It has excellent thermal stability, flame retardancy, chemical stability and corrosion resistance, and has high hardness and strength. Therefore, it is widely used in aerospace, military equipment and automobile manufacturing. However, pure PPS is brittle and has poor wear resistance. It cannot meet the application requirements in areas requiring high wear resistance. It must be modified or reinforced with materials to improve its friction and wear performance. Generally, the friction and wear performance of PPS is improved by adding fillers such as fibers and solid lubricants or liquid lubricants. However, in many fields, such as bearings, bushings or gears, it still cannot meet the wear resistance requirements. Therefore, the use of self-lubricating and wear-resistant PPS modified materials with excellent performance as equipment parts has great practical significance and value.

[0003] CN115785671A discloses an aerogel / polyphenylene sulfide self-lubricating friction material. The material is obtained by melt-extruding a mixture of polyphenylene sulfide, aerogel, reinforcing fibers, and a liquid adjuvant. The polyphenylene sulfide material is modified by using aerogel with low thermal conductivity and high porosity and reinforcing fibers, significantly reducing the material's coefficient of friction. However, melt blending, which uniformly disperses the PPS matrix and aerogel, is essentially a physical blending modification. The system suffers from insufficient stability, prone to migration and agglomeration, resulting in poor wear resistance.

[0004] The inventors previously disclosed a low-friction polyphenylene sulfide material in patent CN 116925547 B. This material is formed by coating the microstructure of polyphenylene sulfide powder particles with a layer of polymer aerogel to form a composite phase interface. This is then melt-compounded with other components to form a polyphenylene sulfide composite material. When friction occurs with other materials, the composite phase interface within the polyphenylene sulfide microstructure blocks or reduces the transfer of heat generated by friction to the polyphenylene sulfide material, reducing material creep. Furthermore, the composite phase interface within the polyphenylene sulfide microstructure reduces frictional forces, thereby lowering the material's friction coefficient and improving wear resistance. In practice, the polyphenylene sulfide powder particles are coated with a polyimide gel containing a metal sulfide and a polar solvent. This is then heat-treated in a vacuum oven to convert the polyimide gel into an aerogel, resulting in interface-modified polyphenylene sulfide powder particles. During the vacuum oven treatment, the metal sulfide reacts with the residual Cl bonds at the ends of the polyphenylene sulfide molecular chains. It may also react with the carboxyl groups at the ends of the polyimide polymer in the polyimide gel, resulting in stronger adhesion of the polyimide gel to the surface of the polyphenylene sulfide particles. The polar solvent in the polyimide gel gradually evaporates during this heating process, forming a polyimide aerogel and a solid-gas composite phase interface at the polyphenylene sulfide interface. The friction coefficient of the polyphenylene sulfide material after interfacial modification is reduced, but its wear resistance and mechanical strength still need to be improved. Summary of the Invention

[0005] To address the unsatisfactory wear resistance and mechanical strength of polyphenylene sulfide in the prior art, the present invention provides a self-lubricating, wear-resistant polyphenylene sulfide-based composite material and its preparation method. The present invention first modifies the surface of polyphenylene sulfide particles with polydopamine to form polyphenylene sulfide@polydopamine microspheres. The microspheres are then coated with a benzimidazole-based fluorinated polyimide gel, followed by freeze-drying to form a composite interface, producing interface-modified polyphenylene sulfide particles. Finally, the interface-modified polyphenylene sulfide particles are compounded with other reinforcing materials to form a polyphenylene sulfide-based composite material that exhibits excellent wear resistance and mechanical strength while maintaining a low coefficient of friction.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A self-lubricating, wear-resistant polyphenylene sulfide-based composite material comprises the following raw materials in parts by weight: 75-90 parts of interface-modified polyphenylene sulfide particles, 5-10 parts of polytetrafluoroethylene particles, 10-20 parts of reinforcing fibers, and 0.2-1 part of a lubricant. The interface-modified polyphenylene sulfide particles are obtained by polymerizing dopamine on the surface of the polyphenylene sulfide particles to form polyphenylene sulfide@polydopamine (PPS@PDA) microspheres, coating the microspheres with a benzimidazole-type fluorinated polyimide gel, and then freeze-drying the microspheres to form a composite phase interface. The amount of dopamine used is 1-3 wt% of the polyphenylene sulfide particles, and the amount of the benzimidazole-type fluorinated polyimide gel used is 20-30 wt% of the PPS@PDA microspheres.

[0008] Furthermore, the amount of dopamine used is 2-3 wt% of the polyphenylene sulfide particles; the amount of benzimidazole fluorinated polyimide gel used is 25-30 wt% of the PPS@PDA microspheres.

[0009] Furthermore, the benzimidazole fluorinated polyimide gel is obtained by reacting fluorinated dianhydride, benzimidazole diamine, and 1,3,5-benzenetricarboxylic acid chloride to obtain benzimidazole fluorinated polyamic acid, which is then imidized; the molar ratio of the fluorinated dianhydride, benzimidazole diamine, and 1,3,5-benzenetricarboxylic acid chloride is 1: (1.05-1.15): (0.01-0.02); the reaction is carried out in a polar organic solvent, and the polar organic solvent accounts for 55-70wt%.

[0010] Furthermore, the fluorinated dianhydride is selected from at least one of 4,4'-hexafluoroisopropylidenephthalic anhydride (6FDA) and 4,4'-[2,2,2-trifluoro-1-(3-trifluoromethyl-phenyl)ethylidene]diphthalic anhydride (TFDA);

[0011] The benzimidazole diamine is selected from at least one of benzimidazole-1,2-diamine, 1H-benzo[D]imidazole-5,6-diamine, 1H-benzo[D]imidazole-2,5-diamine, 1H-benzo[D]imidazole-2,7-diamine, and 5,6-dimethyl-1H-benzo[D]imidazole-4,7-diamine; and the polar organic solvent is at least one of N,N′-dimethylacetamide (DMAC), N,N′-dimethylformamide (DMF), and N-methylpyrrolidone (NMP).

[0012] Furthermore, the benzimidazole fluorinated polyimide gel is prepared by a preparation method comprising the following steps:

[0013] (P1) Under an inert atmosphere, a benzimidazole diamine is dissolved in a polar organic solvent, a fluorinated dianhydride is added, and a pre-condensation reaction is carried out at 5-10° C. for 4-6 hours, followed by the addition of 1,3,5-benzenetricarboxylic acid chloride and a continued reaction for 0.5-1 hour to obtain a benzimidazole fluorinated polyamic acid solution;

[0014] (P2) adding a water-carrying agent to a benzimidazole-based fluorinated polyamic acid solution, heating the solution to 180-220° C. to carry out an imine condensation reaction until no water is discharged, cooling the solution to room temperature, and aging the solution to obtain a benzimidazole-based fluorinated polyimide gel.

[0015] Furthermore, the inert atmosphere in step (P1) is at least one of nitrogen or argon.

[0016] Furthermore, in step (P2), the water-carrying agent is at least one of toluene and xylene, and the amount of the water-carrying agent is 0.8 to 1.2 times the mass of the organic polar solvent; and the aging time is 3 to 5 days.

[0017] Furthermore, the number average molecular weight of the polyphenylene sulfide is 30,000 to 50,000.

[0018] Furthermore, the interface-modified polyphenylene sulfide particles are prepared by a preparation method comprising the following steps:

[0019] (S1) adding polyphenylene sulfide particles and dopamine to a Tris-HCl buffer solution, stirring and reacting at 20-30° C. for 4-8 hours. After the reaction is completed, the polydopamine-modified polyphenylene sulfide particles, i.e., PPS@PDA microspheres, are obtained by centrifugation, washing, and drying.

[0020] (S2) PPS@PDA microspheres and benzimidazole-based fluorinated polyimide gel are stirred and mixed in a ball rolling machine to coat the surface of the PPS@PDA microspheres with a layer of benzimidazole-based fluorinated polyimide gel; and then freeze-dried to convert the benzimidazole-based fluorinated polyimide gel into aerogel that coats the surface of the PPS@PDA microspheres, thereby obtaining interface-modified polyphenylene sulfide particles.

[0021] Furthermore, in step (S1), the concentration of the Tris-HCl buffer solution is 10-30 mM, and the pH is 8.0-9.0; the volume ratio of the mass of the dopamine to the Tris-HCl buffer solution is 1-3 g:1000 mL; and the drying is performed in a vacuum oven at 60-80°C for 12-24 hours. The stirring reaction time in step (S1) needs to be controlled within an appropriate range. If the stirring reaction time is too short, the modification amount of polydopamine is too low, and the effect is limited; if the stirring reaction time is too long, the modification amount is too high, and the PPS@PDA microspheres are prone to adhesion.

[0022] Furthermore, in step (S2), the stirring and mixing conditions are: a rolling ball machine speed of 100 to 200 rpm, and a time of 1 to 2 hours; the freeze-drying conditions are: first freezing in liquid nitrogen for 0.5 to 1 hour, and then vacuum drying in a cold trap at -50 to -40°C for 24 to 48 hours, and a vacuum degree of 10 to 30 Pa.

[0023] Furthermore, the particle size of the interface-modified polyphenylene sulfide particles is 10 to 60 μm, and the particle size of the polytetrafluoroethylene particles is 5 to 15 μm.

[0024] Furthermore, the reinforcing fiber is at least one of glass fiber, carbon fiber, chopped aramid fiber, and basalt fiber; the reinforcing fiber has a diameter of 2 to 10 μm and a length of 1 to 3 mm.

[0025] Furthermore, the lubricant is at least one of amino silicone oil, methyl silicone oil, ethyl silicone oil, and polyether modified silicone oil.

[0026] In a second aspect, the present invention also provides a method for preparing the above-mentioned wear-resistant self-lubricating polyphenylene sulfide-based composite material, comprising the following steps: mixing interface-modified polyphenylene sulfide particles with polytetrafluoroethylene particles, reinforcing fibers, and a lubricant, and then kneading and extruding to obtain a wear-resistant self-lubricating polyphenylene sulfide-based composite material.

[0027] Furthermore, the mixing and extrusion is carried out in a twin-screw extruder at an extrusion temperature of 280-320° C.; and granulation is further included after the mixing and extrusion.

[0028] The present invention first uses dopamine to undergo a self-polymerization oxidation reaction under alkaline conditions to modify the surface of polyphenylene sulfide particles with polydopamine to form PPS@PDA microspheres; then, a fluorinated dibasic anhydride, a benzimidazole diamine, and a cross-linking agent, 1,3,5-benzenetricarboxylic acid chloride, are reacted to prepare a benzimidazole fluorinated polyimide gel, which is coated on the surface of the PPS@PDA microspheres and then freeze-dried to form a composite phase interface. During the freeze-drying process, the organic polar solvent in the benzimidazole fluorinated polyimide gel slowly evaporates, and the gel gradually transforms into an aerogel that is coated on the surface of the PPS@PDA microspheres. Compared with conventional polyimide aerogels, the introduction of benzimidazole-based fluorinated polyimide aerogels significantly improved the wear resistance of polyphenylene sulfide particles. This is likely due to the improved wear resistance caused by the introduction of benzimidazole heterocycles and fluorine atoms in the imidazole-based fluorinated polyimide. Furthermore, the introduction of the crosslinker 1,3,5-benzenetricarboxylic acid chloride increased the density of the imidazole-based fluorinated polyimide. Furthermore, the strong adhesion of polydopamine on the PPS@PDA microspheres enhanced the interfacial forces between the polyphenylene sulfide particles and the benzimidazole-based fluorinated polyimide aerogel. Furthermore, the hydroxyl groups in polydopamine reacted with the terminal amino groups in the imidazole-based fluorinated polyimide, further increasing the density of the benzimidazole-based fluorinated polyimide, thereby improving the mechanical strength and wear resistance of the interface-modified polyphenylene sulfide particles. In summary, the polyphenylene sulfide-based composite materials formed by polydopamine modification and coating with benzimidazole fluorinated polyimide aerogel and compounding with other reinforcing materials have good wear resistance and low friction coefficient.

[0029] The present invention forms interface-modified polyphenylene sulfide particles by polydopamine modification and coating with benzimidazole fluorinated polyimide aerogel, and the polyphenylene sulfide-based composite material formed by compounding the particles with other reinforcing materials has excellent wear resistance and mechanical strength while maintaining a low friction coefficient. DETAILED DESCRIPTION

[0030] Below in conjunction with specific embodiment, the present invention is further described, but is not limited to the content on the specification sheets.Unless otherwise specified, " part " described in the embodiment of the present invention is all weight part.Unless otherwise specified, all reagents used are commercially available reagents in this area.

[0031] Polyphenylene sulfide particles, with a number average molecular weight of approximately 42,000 and a particle size of approximately 30 μm, were obtained from Chongqing Jushi New Material Technology Co., Ltd.

[0032] Polytetrafluoroethylene particles, with a particle size of about 8 μm, were selected from Zhejiang Ge Rui New Materials Co., Ltd.;

[0033] Glass fiber, about 8 μm in diameter and 2 mm in length, was purchased from China Jushi Co., Ltd.;

[0034] Dopamine and Tris-HCl buffer solution were selected from Aladdin Reagent Company.

[0035] Preparation of benzimidazole fluorinated polyimide gel

[0036] Preparation Example 1

[0037] (P1) A three-necked flask equipped with a stirrer and a reflux air cooler was added with 155.6 g (1.05 mol) of 1H-benzo[D]imidazole-5,6-diamine and 1000 g of N,N′-dimethylacetamide (DMAC), and stirred for 30 min under nitrogen to completely dissolve the mixture. 444.2 g (1 mol) of 4,4′-hexafluoroisopropylidenephthalic anhydride (6FDA) was then added and pre-polycondensed at 6±1° C. for 6 h. 2.66 g (0.01 mol) of 1,3,5-benzenetricarboxylic acid chloride was then added and the reaction was continued for 0.5 h to obtain a benzimidazole-based fluorinated polyamic acid solution.

[0038] (P2) 800 g of toluene was added as a water-carrying agent to the above-mentioned benzimidazole-based fluorinated polyamic acid solution, and the solution was heated to 200° C. to carry out an imine condensation reaction until no water was discharged. The solution was cooled to room temperature and aged for 3 days to obtain a benzimidazole-based fluorinated polyimide gel a.

[0039] Preparation Example 2

[0040] (P1) A three-necked flask equipped with a stirrer and a reflux air cooler was added with 170.4 g (1.15 mol) of benzimidazole-1,2-diamine and 1000 g of N,N′-dimethylacetamide (DMAC), and stirred for 30 min under nitrogen to completely dissolve the mixture. 444.2 g (1 mol) of 4,4′-hexafluoroisopropylidenephthalic anhydride (6FDA) was then added and pre-polycondensed at 8±1° C. for 4 h. 5.32 g (0.02 mol) of 1,3,5-benzenetricarboxylic acid chloride was then added and the reaction was continued for 0.5 h to obtain a benzimidazole fluorinated polyamic acid solution.

[0041] (P2) 800 g of toluene was added as a water-carrying agent to the above-mentioned benzimidazole-based fluorinated polyamic acid solution, and the solution was heated to 210° C. to carry out an imine condensation reaction until no water was discharged. The solution was cooled to room temperature and aged for 3 days to obtain a benzimidazole-based fluorinated polyimide gel b.

[0042] Comparative Preparation Example 1

[0043] (P1) A three-necked flask equipped with a stirrer and a reflux air cooler was added with 210.2 g (1.05 mol) of 4,4′-diaminodiphenyl ether (ODA) and 1000 g of N,N′-dimethylacetamide (DMAC), and stirred for 30 min under nitrogen until completely dissolved. 294.2 g (1 mol) of 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA) was then added and pre-polycondensed at 6±1° C. for 6 h. 2.66 g (0.01 mol) of 1,3,5-benzenetricarboxylic acid chloride was then added and the reaction was continued for 0.5 h to obtain a polyamic acid solution.

[0044] (P2) 800 g of toluene was added to the polyamic acid solution as a water-carrying agent, and the solution was heated to 200° C. to carry out an imide condensation reaction until no water was discharged. The solution was cooled to room temperature and aged for 3 days to obtain a polyimide gel.

[0045] Example 1

[0046] (S1) 100 g of polyphenylene sulfide particles and 1 g of dopamine were added to 1000 mL of Tris-HCl buffer solution (Ph = 8.0, 10 mM) and stirred at 20°C for 6 h. After the reaction was completed, the mixture was centrifuged, washed, and dried at 80°C for 12 h to obtain polydopamine-modified polyphenylene sulfide particles, i.e., PPS@PDA microspheres;

[0047] (S2) 100 parts of PPS@PDA microspheres and 20 parts of the benzimidazole-based fluorinated polyimide gel a prepared in Preparation Example 1 were subjected to a rolling process at 150 rpm for 1 hour to coat the surface of the PPS@PDA microspheres with a layer of the benzimidazole-based fluorinated polyimide gel; the microspheres were then frozen in liquid nitrogen for 0.5 hour and then freeze-dried in a freeze dryer at -50°C under a vacuum of 20 Pa for 24 hours to convert the benzimidazole-based fluorinated polyimide gel into an aerogel that coated the surface of the PPS@PDA microspheres, thereby obtaining interface-modified polyphenylene sulfide particles;

[0048] (S3) 75 parts of interface-modified polyphenylene sulfide particles are mixed with 5 parts of polytetrafluoroethylene particles, 10 parts of glass fiber, and 0.2 parts of lubricant methyl silicone oil, and then mixed and extruded through a twin-screw extruder (a total of 6 working zones, zone 1: 280°C, zone 2: 300°C, zone 3: 310°C, zone 4: 320°C, zone 5: 300°C, zone 6: 290°C) and granulated to obtain a wear-resistant and self-lubricating polyphenylene sulfide-based composite material.

[0049] Example 2

[0050] The rest is the same as Example 1, except that: in step (S1), the amount of dopamine used is 2 g, and in step (S2), the amount of benzimidazole fluorinated polyimide gel a prepared in Preparation Example 1 used is 25 parts.

[0051] Example 3

[0052] The rest is the same as Example 1, except that: in step (S1), the amount of dopamine used is 3 g, and in step (S2), the amount of benzimidazole fluorinated polyimide gel a prepared in Preparation Example 1 used is 30 parts.

[0053] Example 4

[0054] The rest is the same as Example 1, except that in step (S2), the benzimidazole-based fluorinated polyimide gel b prepared in Preparation Example 2 is used to replace the benzimidazole-based fluorinated polyimide gel a prepared in Preparation Example 1.

[0055] Example 5

[0056] The rest is the same as Example 1, except that in step (S3), the amount of each material used is: 90 parts of interface-modified polyphenylene sulfide particles, 10 parts of polytetrafluoroethylene particles, 20 parts of glass fiber, and 1 part of lubricant methyl silicone oil.

[0057] Comparative Example 1

[0058] The rest is the same as Example 1, except that step (S1) is omitted, and polyphenylene sulfide particles are used instead of PPS@PDA microspheres in step (S2), that is, polyphenylene sulfide is not polymerized on its surface by dopamine.

[0059] Comparative Example 2

[0060] The rest is the same as Example 1, except that in step (S2), the polyimide gel prepared in Comparative Preparation Example 1 is used to replace the benzimidazole fluorinated polyimide gel a prepared in Preparation Example 1.

[0061] Testing and Analysis

[0062] The polyphenylene sulfide-based composite materials obtained in the above examples and comparative examples were subjected to the following performance tests:

[0063] Tensile strength: tested in accordance with national standard GB / T1040;

[0064] Impact strength: tested in accordance with national standard GB / T1843;

[0065] Friction coefficient and wear rate: Tested using an M-200 ring-block test rig in accordance with the national standard GB / T3960-2016. Test conditions: room temperature, titanium alloy rings as the friction pair, initial end surface roughness Ra = 0.25 μm, test load of 100 N, sliding speed of 0.5 m / s, and friction and wear test duration of 3 hours.

[0066] The test results are shown in Table 1.

[0067] Table 1 Performance test of polyphenylene sulfide-based composite materials

[0068]

[0069]

[0070] It can be seen from Table 1 that the polyphenylene sulfide-based composite material prepared in the present invention has excellent wear resistance and mechanical strength while maintaining a low friction coefficient.

Claims

1. A self-lubricating and wear-resistant polyphenylene sulfide-based composite material, characterized in that: The invention comprises the following raw materials in parts by weight: 75-90 parts of interface-modified polyphenylene sulfide particles, 5-10 parts of polytetrafluoroethylene particles, 10-20 parts of reinforcing fibers, and 0.2-1 parts of lubricant; the interface-modified polyphenylene sulfide particles are prepared by polymerizing dopamine on the surface of polyphenylene sulfide particles to form polyphenylene sulfide@polydopamine (PPS@PDA) microspheres, coating them with benzimidazole fluorinated polyimide gel, and then freeze-drying to form a composite phase interface; the amount of dopamine is 1-3wt% of the polyphenylene sulfide particles, and the amount of benzimidazole fluorinated polyimide is 1-3wt%. The amount of imide gel used is 20-30wt% of the PPS@PDA microspheres; the benzimidazole fluorinated polyimide gel is obtained by reacting fluorinated dianhydride, benzimidazole diamine, and 1,3,5-benzenetricarboxylic acid chloride to obtain benzimidazole fluorinated polyamic acid, which is then imidized; the molar ratio of the fluorinated dianhydride, benzimidazole diamine, and 1,3,5-benzenetricarboxylic acid chloride is 1:(1.05-1.15):(0.01-0.02), and the reaction is carried out in a polar organic solvent, with the polar organic solvent accounting for 55-70wt%.

2. The self-lubricating and wear-resistant polyphenylene sulfide-based composite material according to claim 1, characterized in that: The amount of dopamine used is 2-3 wt % of the polyphenylene sulfide particles, and the amount of the benzimidazole fluorinated polyimide gel used is 25-30 wt % of the PPS@PDA microspheres.

3. The self-lubricating and wear-resistant polyphenylene sulfide-based composite material according to claim 1, characterized in that: The fluorinated dianhydride is selected from at least one of 4,4'-hexafluoroisopropylidenephthalic anhydride (6FDA) and 4,4'-[2,2,2-trifluoro-1-(3-trifluoromethyl-phenyl)ethylene]diphthalic anhydride (TFDA); the benzimidazole diamine is selected from at least one of benzimidazole-1,2-diamine, 1H-benzo[D]imidazole-5,6-diamine, 1H-benzo[D]imidazole-2,5-diamine, 1H-benzo[D]imidazole-2,7-diamine, and 5,6-dimethyl-1H-benzo[D]imidazole-4,7-diamine; and the polar organic solvent is at least one of N,N'-dimethylacetamide (DMAC), N,N'-dimethylformamide (DMF), and N-methylpyrrolidone (NMP).

4. The self-lubricating and wear-resistant polyphenylene sulfide-based composite material according to claim 1, characterized in that: The benzimidazole fluorinated polyimide gel is prepared by a preparation method comprising the following steps: (P1) Under an inert atmosphere, a benzimidazole diamine is dissolved in a polar organic solvent, a fluorinated dianhydride is added, and the mixture is pre-polycondensed at 5-10°C for 4-6 hours, followed by the addition of 1,3,5-benzenetricarboxylic acid chloride and the reaction is continued for 0.5-1 hour to obtain a benzimidazole fluorinated polyamic acid solution; (P2) Adding a water-carrying agent to a benzimidazole-based fluorinated polyamic acid solution, heating to 180-220° C. to carry out an imine condensation reaction until no water is discharged, cooling to room temperature and aging to obtain a benzimidazole-based fluorinated polyimide gel.

5. The self-lubricating and wear-resistant polyphenylene sulfide-based composite material according to claim 1, characterized in that: The number average molecular weight of the polyphenylene sulfide is 30,000 to 50,000.

6. The self-lubricating and wear-resistant polyphenylene sulfide-based composite material according to claim 1, characterized in that: The interface-modified polyphenylene sulfide particles are prepared by a preparation method comprising the following steps: (S1) Adding polyphenylene sulfide particles and dopamine to a Tris-HCl buffer solution and stirring the mixture at 20-30°C for 4-8 hours. After the reaction is complete, the mixture is centrifuged, washed, and dried to obtain polydopamine-modified polyphenylene sulfide particles, i.e., PPS@PDA microspheres. (S2) PPS@PDA microspheres and benzimidazole-based fluorinated polyimide gel are stirred and mixed in a ball rolling machine to coat the surface of the PPS@PDA microspheres with a layer of benzimidazole-based fluorinated polyimide gel; the microspheres are then freeze-dried to convert the benzimidazole-based fluorinated polyimide gel into aerogel that coats the surface of the PPS@PDA microspheres, thereby obtaining interface-modified polyphenylene sulfide particles.

7. The self-lubricating and wear-resistant polyphenylene sulfide-based composite material according to claim 6, characterized in that: In step (S1), the concentration of the Tris-HCl buffer solution is 10-30 mM, and the pH is 8.0-9.0; the volume ratio of the dopamine mass to the Tris-HCl buffer solution is 1-3 g:1000 mL; the drying is performed in a vacuum oven at 60-80° C. for 12-24 hours; and / or In step (S2), the stirring and mixing conditions are: a ball rolling machine speed of 100-200 rpm, and a time of 1-2 hours; the freeze-drying conditions are: first freezing in liquid nitrogen for 0.5-1 hour, and then vacuum drying in a cold trap at -50-40°C for 24-48 hours, and a vacuum degree of 10-30 Pa.

8. The self-lubricating and wear-resistant polyphenylene sulfide-based composite material according to claim 1, characterized in that: The particle size of the interface-modified polyphenylene sulfide particles is 10-60 μm, and the particle size of the polytetrafluoroethylene particles is 5-15 μm; and / or The reinforcing fiber is at least one of glass fiber, carbon fiber, chopped aramid fiber, and basalt fiber; the reinforcing fiber has a diameter of 2 to 10 μm and a length of 1 to 3 mm; and / or The lubricant is at least one of amino silicone oil, methyl silicone oil, ethyl silicone oil, and polyether modified silicone oil.

9. The method for preparing the self-lubricating and wear-resistant polyphenylene sulfide-based composite material according to any one of claims 1 to 8, characterized in that: The following steps are involved: The interface-modified polyphenylene sulfide particles are mixed with polytetrafluoroethylene particles, reinforcing fibers and a lubricant, and then mixed and extruded to obtain a wear-resistant self-lubricating polyphenylene sulfide-based composite material.

10. The preparation method according to claim 9, characterized in that The mixing and extrusion is carried out in a twin-screw extruder at an extrusion temperature of 280-320° C.; granulation is also performed after the mixing and extrusion.

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