High-temperature-resistant organic fiber composite liner material as well as preparation method and application thereof

Abstract

The invention provides a high-temperature-resistant organic fiber composite liner material as well as a preparation method and application thereof, and relates to the technical field of solid lubrication. The composite filler provided by the invention comprises a first hybrid filler and a second hybrid filler, the first hybrid filler comprises a montmorillonite nanosheet and a Co-MOF (Metal Organic Framework) nanoflower grown on the surface of the montmorillonite nanosheet; the second hybrid filler comprises a polydopamine modified boron nitride nanosheet and silver nanoparticles loaded on the surface of the polydopamine modified boron nitride nanosheet in situ. The composite filler is introduced into the organic fiber composite liner material, and the high-temperature friction and wear performance of the organic fiber composite liner material can be effectively improved by exerting the bearing and lubricating performance and the synergistic enhancement effect of the two hybrid fillers. The result of the embodiment shows that the organic fiber composite liner material introduced with the composite filler shows excellent high-temperature wear resistance and lubricating performance at the temperature of 350 DEG C.

Description

Technical Field

[0001] The present invention relates to the technical field of solid lubrication, and particularly relates to a composite filler, a high-temperature resistant organic fiber composite gasket material, and a preparation method and application thereof. Background Art

[0002] The friction and wear performance of organic fiber composite gasket materials has an important impact on the service performance and service life of many moving parts such as aircraft landing gears, engine nacelles, fan blade roots, and aircraft flaps and ailerons. Therefore, how to ensure the long-term stable and effective operation of organic fiber composite gasket materials under extreme working conditions is particularly important.

[0003] When the organic fiber composite gasket material operates under high-temperature extreme working conditions, phenomena such as surface resin shedding and fiber pulling out will occur, and then serious wear will occur. Therefore, inhibiting the softening and degradation of the resin matrix, improving its load-bearing and wear-resistant performance, and promoting the formation of a high-quality friction transfer film are of great significance for realizing the stable service of organic fiber composite gasket materials under extreme working conditions. Introducing lubricating additives into organic fiber composite gasket materials is an important way to improve the friction and wear performance of gasket materials.

[0004] In previous studies, researchers introduced some nano-fillers as lubricating additives into gasket materials, such as metal oxides, carbon-based fillers or ceramic particles, to improve the high-temperature friction performance of gasket materials. However, these filler reinforcements are often limited by their poor dispersion performance and single reinforcement function, and cannot effectively enhance the high-temperature friction performance of gasket materials. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a composite filler, a high-temperature resistant organic fiber composite gasket material, and a preparation method and application thereof. The composite filler provided by the present invention has good dispersibility and can effectively enhance the high-temperature tribological performance of organic fiber composite gasket materials.

[0006] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0007] The present invention provides a composite filler, comprising a first hybrid filler and a second hybrid filler;

[0008] The first hybrid filler includes montmorillonite nanosheets and Co-MOF nanoflowers grown on the surface of the montmorillonite nanosheets. The montmorillonite nanosheets are obtained by intercalation modification of montmorillonite with cetyltrimethylammonium bromide, and the Co-MOF nanoflowers are formed by coordination of cobalt ions and 2-methylimidazole;

[0009] The second hybrid filler includes polydopamine-modified boron nitride nanosheets and silver nanoparticles in-situ loaded on the surface of the polydopamine-modified boron nitride nanosheets;

[0010] The mass ratio of the first hybrid filler to the second hybrid filler is (0.5 - 2):(0.5 - 2).

[0011] Preferably, the preparation method of the first hybrid filler includes the following steps:

[0012] Intercalation modification of montmorillonite with cetyltrimethylammonium bromide to obtain organically modified montmorillonite;

[0013] Mixing the organically modified montmorillonite with cobalt nitrate, 2-methylimidazole and an organic solvent for solvothermal reaction to obtain the first hybrid filler.

[0014] Preferably, the mass ratio of the montmorillonite to cetyltrimethylammonium bromide is 1:(0.2 - 0.5), the temperature of the intercalation modification is 60 - 90 °C, and the time is 2 - 5 h; the mass ratio of the cobalt nitrate to 2-methylimidazole is 6.5:1, the mass ratio of the organically modified montmorillonite to cobalt nitrate is 1:(0.5 - 0.8), the temperature of the solvothermal reaction is 80 - 100 °C, and the time is 20 - 30 h.

[0015] Preferably, the preparation method of the second hybrid filler includes the following steps:

[0016] Mixing boron nitride nanosheets, Tris-HCl buffer solution and dopamine hydrochloride for oxidative self-polymerization to obtain polydopamine-modified boron nitride nanosheets;

[0017] Mixing the polydopamine-modified boron nitride nanosheets with an organic solvent and silver acetate for an adsorption reaction to obtain polydopamine-modified boron nitride nanosheets adsorbed with silver ions;

[0018] In-situ reducing the polydopamine-modified boron nitride nanosheets adsorbed with silver ions with sodium dihydrogen phosphate to obtain the second hybrid filler.

[0019] Preferably, the mass ratio of the polydopamine-modified boron nitride nanosheets to silver acetate is (2 - 4):1; the mass ratio of the sodium dihydrogen phosphate to silver acetate is 1:1; the temperature of the adsorption reaction is room temperature, and the time is 8 - 12 h; the temperature of the in-situ reduction is 60 - 80 °C, and the time is 3 - 5 h.

[0020] The present invention provides the application of the composite filler as described in the above technical solutions in the preparation of high-temperature resistant organic fiber composite gasket materials.

[0021] The present invention provides a high-temperature resistant organic fiber composite gasket material, which comprises a polyimide fiber-polytetrafluoroethylene fiber blended fiber fabric and a polyimide resin composite material compounded on the blended fiber fabric; the polyimide resin composite material comprises a polyimide resin and reinforcing fillers dispersed in the polyimide resin, and the reinforcing fillers are the composite fillers described in the above technical solution.

[0022] Preferably, the mass fraction of the polyimide resin composite material in the high-temperature resistant organic fiber composite gasket material is 15-40%, and the masses of the first hybrid filler and the second hybrid filler in the polyimide resin composite material are respectively 0.5-2% of the mass of the polyimide resin.

[0023] The present invention provides a preparation method of the high-temperature resistant organic fiber composite gasket material described in the above technical solution, which comprises the following steps:

[0024] Mix the first hybrid filler, the second hybrid filler and the polyimide resin solution to obtain an impregnating solution;

[0025] Immerse the polyimide fiber-polytetrafluoroethylene fiber blended fiber fabric in the impregnating solution, and obtain a fabric prepreg after drying;

[0026] Cure the fabric prepreg to obtain the high-temperature resistant organic fiber composite gasket material.

[0027] The present invention provides the application of the high-temperature resistant organic fiber composite gasket material described in the above technical solution or the high-temperature resistant organic fiber composite gasket material prepared by the preparation method described in the above technical solution in the friction field.

[0028] The composite filler provided by the present invention comprises a first hybrid filler and a second hybrid filler; the first hybrid filler comprises montmorillonite nanosheets and Co-MOF nanoflowers grown on the surface of the montmorillonite nanosheets; the second hybrid filler comprises polydopamine-modified boron nitride nanosheets and silver nanoparticles in-situ loaded on the surface of the polydopamine-modified boron nitride nanosheets; the mass ratio of the first hybrid filler to the second hybrid filler is (0.5-2):(0.5-2). In the present invention, the growth of Co-MOF nanoflowers on the surface of montmorillonite nanosheets integrates the excellent high-temperature load-bearing performance of montmorillonite nanosheets and Co-MOF nanoflowers, realizing the synergistic enhancement effect of fillers with different dimensions on the high-temperature load-bearing performance of the organic fiber composite liner material; moreover, the growth of Co-MOF nanoflowers on the surface of montmorillonite nanosheets can effectively reduce the surface energy of montmorillonite nanosheets, inhibit the stacking of montmorillonite nanosheets, and at the same time, Co-MOF presents a nanoflower shape and adsorbs on the surface of montmorillonite nanosheets, forming a multi-scale heterojunction morphology, which is beneficial to its effective dispersion inside the resin matrix and simultaneously exerts the synergistic lubrication function of montmorillonite nanosheets and Co-MOF. The in-situ loading of silver nanoparticles on the surface of boron nitride nanosheets can effectively solve the agglomeration of silver nanoparticles and fully exert its effective high-temperature lubrication function of soft metal; meanwhile, boron nitride nanosheets themselves, as an advanced two-dimensional ceramic nanomaterial, also have excellent high-temperature lubrication performance. Introducing the composite filler provided by the present invention into the organic fiber composite liner material can effectively improve the high-temperature friction and wear performance of the organic composite liner material by exerting the load-bearing and lubrication performance of the first hybrid filler and the second hybrid filler and the synergistic enhancement effect.

[0029] The present invention provides a high-temperature resistant organic fiber composite liner material, comprising a polyimide fiber-polytetrafluoroethylene fiber blended fiber fabric and a polyimide resin composite material compounded on the blended fiber fabric; the polyimide resin composite material comprises a polyimide resin and reinforcing fillers dispersed in the polyimide resin, and the reinforcing fillers are the composite fillers described in the above technical solution. The high-temperature resistant organic fiber composite liner material provided by the present invention is an organic fiber composite liner material jointly reinforced by a first hybrid filler and a second hybrid filler, and has excellent friction reduction and wear resistance performance under high-temperature working conditions (up to 350 °C). The results of the examples show that the high-temperature resistant organic fiber composite liner material provided by the present invention has a friction coefficient of 0.0377-0.0512 and a wear rate of (0.89-1.11)×10 -14 m 3 (Nm) -1 , showing excellent high-temperature wear resistance and lubrication performance. Description of the Drawings

[0030] Figure 1Wear rate and friction coefficient diagrams of the high-temperature resistant organic fiber composite gasket materials prepared in Comparative Example 3 and Example 1 Figure 1 Among them, (a) is the friction coefficient diagram, and (b) is the wear rate diagram;

[0031] Figure 2 Morphology photos of the samples after wear in Example 1 and Comparative Example 3 Figure 2 Among them, (a) is the morphology photo of the sample after wear in Example 1, and (b) is the morphology photo of the sample after wear in Comparative Example 3. Specific implementation manners

[0032] The present invention provides a composite filler, including a first hybrid filler and a second hybrid filler;

[0033] The first hybrid filler includes montmorillonite nanosheets and Co-MOF nanoflowers grown on the surface of the montmorillonite nanosheets. The montmorillonite nanosheets are obtained by intercalation modification of montmorillonite with cetyltrimethylammonium bromide. The Co-MOF nanoflowers are formed by coordination of cobalt ions and 2-methylimidazole;

[0034] The second hybrid filler includes polydopamine-modified boron nitride nanosheets and silver nanoparticles in-situ loaded on the surface of the polydopamine-modified boron nitride nanosheets;

[0035] The mass ratio of the first hybrid filler to the second hybrid filler is (0.5 - 2):(0.5 - 2).

[0036] In the present invention, unless otherwise specified, the raw materials involved are well-known commercially available products in the art.

[0037] The composite filler provided by the present invention includes a first hybrid filler. In the present invention, the first hybrid filler includes montmorillonite nanosheets and Co-MOF nanoflowers grown on the surface of the montmorillonite nanosheets. The montmorillonite nanosheets are obtained by intercalation modification of montmorillonite with cetyltrimethylammonium bromide. The Co-MOF nanoflowers are formed by coordination of cobalt ions and 2-methylimidazole. In the present invention, the preparation method of the first hybrid filler preferably includes the following steps:

[0038] Intercalation modification of montmorillonite with cetyltrimethylammonium bromide to obtain organically modified montmorillonite;

[0039] Mixing the organically modified montmorillonite with cobalt nitrate, 2-methylimidazole and an organic solvent for a solvothermal reaction to obtain the first hybrid filler.

[0040] The present invention uses cetyltrimethylammonium bromide (CTAB) to intercalate and modify montmorillonite (MMT) to obtain organically modified montmorillonite (OMMT). In the present invention, the montmorillonite is preferably sodium-based montmorillonite, and the mass ratio of the montmorillonite to cetyltrimethylammonium bromide is preferably 1:(0.2 - 0.5), which can be 1:0.2, 1:0.3, 1:0.4 or 1:0.5. The addition of cetyltrimethylammonium bromide will expand the layer spacing of the montmorillonite. The more the addition amount, the larger the layer spacing of the montmorillonite, which helps to improve the adsorption capacity and ion exchange performance. In the present invention, the temperature of the intercalation modification is preferably 60 - 90 °C, which can be 60, 70, 80 or 90 °C, and the time is preferably 2 - 5 h, which can be 3, 4 or 5 h. The intercalation modification is preferably carried out under the conditions of stirring and reflux. In the present invention, the specific operation of the intercalation modification preferably includes the following steps:

[0041] Mix the montmorillonite and water to obtain a montmorillonite dispersion;

[0042] Dropwise add an ethanol solution of cetyltrimethylammonium bromide to the montmorillonite dispersion for intercalation modification.

[0043] In the present invention, the water is preferably deionized water; the temperature of mixing the montmorillonite and water is preferably 60 - 90 °C, which can be 60, 70, 80 or 90 °C. The mixing is preferably carried out under the conditions of stirring and reflux, and the mixing time is preferably 2 - 5 h, which can be 2, 3, 4 or 5 h. In the present invention, the concentration of montmorillonite in the montmorillonite dispersion is preferably 2 - 10 mg / mL, which can be 2, 5 or 10 mg / mL.

[0044] In the present invention, the volume ratio of the ethanol solution of cetyltrimethylammonium bromide to the montmorillonite dispersion is preferably 1:3, and the concentration of the ethanol solution of cetyltrimethylammonium bromide is determined to satisfy the mass ratio of montmorillonite to cetyltrimethylammonium bromide of 1:(0.2 - 0.5).

[0045] In the present invention, the time of the intercalation modification is calculated starting from the completion of the dropwise addition of the ethanol solution of cetyltrimethylammonium bromide.

[0046] After the intercalation modification is completed, in the present invention, it is preferred to cool the obtained reaction mixture, and then carry out solid-liquid separation, solid-phase washing and freeze-drying in sequence to obtain the organically modified montmorillonite. The present invention has no special requirements for the method of solid-liquid separation, and any well-known solid-liquid separation method in the art can be used, such as suction filtration; the present invention has no special requirements for the processes of washing and freeze-drying, and the corresponding processes well-known to those skilled in the art can be used.

[0047] After obtaining the organically modified montmorillonite, the present invention mixes the organically modified montmorillonite with cobalt nitrate, 2-methylimidazole, and an organic solvent for a solvothermal reaction to obtain the first hybrid filler.

[0048] In the present invention, the mass ratio of cobalt nitrate to 2-methylimidazole is preferably 6.5:1; the mass ratio of the organically modified montmorillonite to cobalt nitrate is preferably 1:(0.5 - 0.8), which can be 1:0.5, 1:0.6, 1:0.7, or 1:0.8. The mass ratio of the modified montmorillonite to cobalt nitrate affects the loading amount of Co-MOF on the surface of montmorillonite in the subsequent formation of the first hybrid filler, and thus affects the dispersibility and friction and wear properties of the filler. In the present invention, the organic solvent is preferably methanol.

[0049] In the present invention, the method of mixing the organically modified montmorillonite with cobalt nitrate, 2-methylimidazole, and an organic solvent is preferably as follows:

[0050] Mix cobalt nitrate with an organic solvent to obtain a cobalt nitrate solution;

[0051] Mix 2-methylimidazole with an organic solvent to obtain a 2-methylimidazole solution;

[0052] Mix the cobalt nitrate solution and the 2-methylimidazole solution, stir evenly to obtain a mixed solution;

[0053] Add the organically modified montmorillonite to the mixed solution and disperse it evenly by ultrasonic treatment.

[0054] In the present invention, the concentration of the cobalt nitrate solution is preferably 3 - 8 mg / mL, which can be 3, 5, or 8 mg / mL; the volume ratio of the cobalt nitrate solution to the 2-methylimidazole solution is preferably 1:1.

[0055] In the present invention, the temperature of the solvothermal reaction is preferably 80 - 100 °C, which can be 80, 90, or 100 °C, and the time is preferably 20 - 30 h, which can be 20, 25, or 30 h; the solvothermal reaction is specifically carried out in a hydrothermal autoclave.

[0056] After the solvothermal reaction is completed, the present invention preferably cools the obtained reaction mixture, and then successively performs solid-liquid separation, solid-phase washing, and freeze-drying to obtain the first hybrid filler. The present invention has no special requirements for the processes of solid-liquid separation, washing, and freeze-drying, and the corresponding processes well-known to those skilled in the art can be adopted.

[0057] Montmorillonite (MMT) is a phyllosilicate mineral with an aquifer-like structure. Due to its unique layered structure, it can be dissociated into nanosheets, and the surface activity of the montmorillonite sheets can be adjusted through organic cation exchange reactions. It has been widely studied because its raw materials are extremely abundant and inexpensive. In this invention, organic modification of montmorillonite is carried out to obtain layered montmorillonite nanosheets, and Co-MOF nanoflowers are in-situ solvothermally grown on their surfaces to construct a multi-level nano-hybrid structure, expanding the interfacial contact area between the hybrid structure and the resin matrix, and simultaneously exerting the synergistic lubrication functions of OMMT and Co-MOF.

[0058] In this invention, the first hybrid filler is denoted as organically modified montmorillonite@metal-organic framework, abbreviated as OMMT@Co-MOF hybrid, which integrates the outstanding load-bearing properties of organically modified montmorillonite and Co-MOF nanoflowers. The introduction of Co-MOF can effectively increase the surface area of montmorillonite nanosheets and promote the dispersion of montmorillonite nanosheets in the resin matrix.

[0059] The composite filler provided by this invention includes a second hybrid filler. In this invention, the second hybrid filler includes polydopamine-modified boron nitride nanosheets and silver nanoparticles in-situ loaded on the surface of the polydopamine-modified boron nitride nanosheets. In this invention, the preparation method of the second hybrid filler preferably includes the following steps:

[0060] Mix boron nitride nanosheets, Tris-HCl buffer solution, and dopamine hydrochloride for oxidative self-polymerization to obtain polydopamine-modified boron nitride nanosheets;

[0061] Mix the polydopamine-modified boron nitride nanosheets with an organic solvent and silver acetate for an adsorption reaction to obtain polydopamine-modified boron nitride nanosheets adsorbed with silver ions;

[0062] In-situ reduce the polydopamine-modified boron nitride nanosheets adsorbed with silver ions with sodium dihydrogen phosphate to obtain the second hybrid filler.

[0063] In this invention, boron nitride nanosheets, Tris-HCl buffer solution, and dopamine hydrochloride are mixed for oxidative self-polymerization to obtain polydopamine-modified boron nitride nanosheets.

[0064] In the present invention, the concentration of the Tris-HCl buffer solution is preferably 1.5 - 2.5 mg / mL, and can be 1.5, 2.0 or 2.5 mg / mL; the pH value is preferably 8 - 9, and can be 8, 8.5 or 9; the dosage ratio of the boron nitride nanosheets to the Tris-HCl buffer solution is preferably 1.0 - 3.0 mg:1 mL, and can be 1.0 mg:1 mL, 2.0 mg:1 mL or 3.0 mg:1 mL; the dosage ratio of dopamine hydrochloride to the Tris-HCl buffer solution is preferably 1.5 - 2.5 mg:1 mL, and can be 1.5 mg:1 mL, 2.0 mg:1 mL or 2.5 mg:1 mL.

[0065] In the present invention, the method for mixing the boron nitride nanosheets, the Tris-HCl buffer solution and dopamine hydrochloride is preferably as follows: the boron nitride nanosheets are dispersed in the Tris-HCl buffer solution to obtain a boron nitride nanosheet dispersion; dopamine hydrochloride is added to the boron nitride nanosheet dispersion. In the present invention, the dispersion is preferably ultrasonic dispersion, and the time of the ultrasonic dispersion is preferably 30 - 60 min, and can be 30, 40, 50 or 60 min; a uniform boron nitride nanosheet dispersion is obtained through the ultrasonic dispersion.

[0066] In the present invention, the oxidative self-polymerization is preferably carried out under the conditions of room temperature and open stirring, and the time of the oxidative self-polymerization is preferably 20 - 30 h, and can be 20, 24, 25 or 30 h. Dopamine hydrochloride undergoes oxidative self-polymerization on the surface of the boron nitride nanosheets to form polydopamine-modified boron nitride nanosheets.

[0067] After the oxidative self-polymerization is completed, it is preferred to sequentially carry out solid-liquid separation, solid-phase washing and freeze-drying on the obtained reaction mixture to obtain the polydopamine-modified boron nitride nanosheets.

[0068] After obtaining the polydopamine-modified boron nitride nanosheets, in the present invention, the polydopamine-modified boron nitride nanosheets are mixed with an organic solvent and silver acetate for an adsorption reaction to obtain polydopamine-modified boron nitride nanosheets adsorbed with silver ions.

[0069] In the present invention, the mass ratio of the polydopamine-modified boron nitride nanosheets to silver acetate is preferably (2 - 4):1, and can be 2:1, 2.5:1, 3:1 or 4:1. In the present invention, the organic solvent is preferably methanol. In the present invention, the polydopamine on the surface of the polydopamine-modified boron nitride nanosheets is used to adsorb silver ions in the solution, and the mass ratio of silver acetate to the polydopamine-modified boron nitride nanosheets will affect the loading amount of silver nanoparticles on the surface of boron nitride, and further affect the dispersion and friction and wear properties of the filler.

[0070] In the present invention, the method for mixing the polydopamine-modified boron nitride nanosheets with an organic solvent and silver acetate is preferably as follows: adding the polydopamine-modified boron nitride nanosheets into an organic solvent, and performing ultrasonic dispersion to obtain a dispersion of polydopamine-modified boron nitride nanosheets; adding silver acetate to the dispersion of polydopamine-modified boron nitride nanosheets. In the present invention, the time for ultrasonic dispersion is preferably 30 min; the concentration of the dispersion of polydopamine-modified boron nitride nanosheets is preferably 1-2 mg / mL, and can be 1, 1.5 or 2 mg / mL.

[0071] In the present invention, the adsorption reaction is preferably carried out at room temperature under stirring; the time for the adsorption reaction is preferably 8-12 h, and can be 8, 10 or 12 h. After the adsorption reaction, silver ions are adsorbed on the surface of the boron nitride nanosheets.

[0072] After the adsorption reaction, in the present invention, the obtained mixed solution is preferably allowed to stand for precipitation, and the supernatant is poured off. The obtained precipitate is the polydopamine-modified boron nitride nanosheets adsorbed with silver ions. In the present invention, the time for standing is preferably 1 h.

[0073] After obtaining the polydopamine-modified boron nitride nanosheets adsorbed with silver ions, the present invention in-situ reduces the polydopamine-modified boron nitride nanosheets adsorbed with silver ions with sodium dihydrogen phosphate to obtain the second hybrid filler.

[0074] In the present invention, the mass ratio of sodium dihydrogen phosphate to silver acetate is preferably 1:1, and sodium dihydrogen phosphate is used as a reducing agent. In the present invention, methanol is preferably added to dilute the above precipitate, and then sodium dihydrogen phosphate is added for in-situ reduction; the volume ratio of methanol to the above-poured-off supernatant is preferably 1:1, and sodium dihydrogen phosphate can also be dissolved in a small amount of methanol and then added.

[0075] In the present invention, the temperature for in-situ reduction is preferably 60-80 °C, and can be 60, 70 or 80 °C, and the time is preferably 3-5 h, and can be 3, 4 or 5 h. The in-situ reduction is preferably carried out under reflux and stirring. After the in-situ reduction, the silver ions are in-situ reduced on the surface of the boron nitride nanosheets.

[0076] After the in-situ reduction, in the present invention, the obtained reaction mixture is preferably cooled, and then solid-liquid separation, solid-phase washing and freeze-drying are carried out in sequence to obtain the second hybrid filler.

[0077] In the present invention, the second hybrid filler is denoted as the BN@Ag hybrid, which integrates the excellent high-temperature lubrication performance of boron nitride nanosheets and silver nanoparticles. At the same time, the presence of boron nitride nanosheets inhibits the agglomeration problem of silver nanoparticles.

[0078] In the present invention, the mass ratio of the first hybrid filler to the second hybrid filler is (0.5 - 2):(0.5 - 2), and it can be 1:1, 1:2 or 1.5:1. In the present invention, the composite filler is specifically a mixture of the first hybrid filler and the second hybrid filler.

[0079] The present invention provides the application of the composite filler as described in the above technical solution in the preparation of a high-temperature resistant organic fiber composite gasket material.

[0080] The composite filler provided by the present invention is introduced into the organic fiber composite gasket material. Among them, the first hybrid filler (OMMT@Co-MOF hybrid) is introduced into the organic fiber composite gasket material, that is, the organically modified montmorillonite nanosheets and Co-MOF nanoflowers are simultaneously introduced into the organic fiber composite gasket material. By exerting the excellent high-temperature load-bearing performance of the organically modified montmorillonite nanosheets and Co-MOF nanoflowers, the synergistic enhancement effect of different-dimensional fillers on the high-temperature load-bearing performance of the organic fiber composite gasket material is realized. The introduction of the second hybrid filler (BN@Ag hybrid) exerts the outstanding high-temperature synergistic lubrication performance of boron nitride nanosheets and silver nanoparticles; at the same time, the loading of silver nanoparticles on the surface of boron nitride nanosheets can effectively inhibit the agglomeration of silver nanoparticles in the gasket material, and thus fully exert its high-temperature lubrication function. The co-introduction of the two hybrid fillers endows the organic fiber composite gasket material with excellent friction and wear reduction performance under high-temperature working conditions by exerting the load-bearing and lubrication performance of the two hybrid fillers and the synergistic enhancement effect.

[0081] The present invention provides a high-temperature resistant organic fiber composite gasket material, which includes a polyimide fiber-polytetrafluoroethylene fiber blended fiber fabric and a polyimide resin composite material compounded on the blended fiber fabric; the polyimide resin composite material includes a polyimide resin and reinforcing fillers dispersed in the polyimide resin, and the reinforcing fillers are the composite fillers as described in the above technical solution.

[0082] In the present invention, the polyimide fiber-polytetrafluoroethylene fiber blended fiber fabric is a blended fiber fabric formed by mixing and interweaving polyimide fibers (PI fibers) and polytetrafluoroethylene fibers (PTFE fibers), preferably woven with polytetrafluoroethylene fibers as the weft yarn and polyimide fibers as the warp yarn. In the embodiments of the present invention, the fineness of the polytetrafluoroethylene fibers is specifically 400 D, and the fineness of the polyimide fibers is specifically 200 D; the warp density of the polyimide fiber-polytetrafluoroethylene fiber blended fabric is preferably 320 - 490 threads / 10 cm, and the weft density is preferably 290 - 350 threads / 10 cm. In the present invention, the tissue structure of the polyimide fiber-polytetrafluoroethylene fiber blended fiber fabric is preferably one or more of plain weave, twill weave, and satin weave; when the tissue structure of the polyimide fiber-polytetrafluoroethylene fiber blended fiber fabric is several of the above, the present invention has no special limitation on the distribution ratio and method of different tissue structures, and any ratio or method is acceptable. The present invention has no special limitation on the specific weaving process of the polyimide fiber-polytetrafluoroethylene fiber blended fiber fabric, and it can be woven according to the process well-known in the art using the above warp density and weft density.

[0083] In the present invention, the mass fraction of the polyimide resin composite material in the high-temperature resistant organic fiber composite gasket material is preferably 15 - 40%, and it can be 15%, 20%, 30%, or 40%; the masses of the first hybrid filler and the second hybrid filler in the polyimide resin composite material are respectively preferably 0.5 - 2% of the mass of the polyimide resin, and they can be 0.5%, 1%, 1.5%, or 2% respectively. The present invention has no special requirements for the polyimide resin, and the polyimide resin well-known to those skilled in the art can be used.

[0084] The organic fiber composite gasket material provided by the present invention is a high-temperature resistant organic fiber composite gasket material jointly reinforced by a first hybrid filler and a second hybrid filler, and it has excellent friction reduction and wear resistance under high-temperature working conditions (up to 350 °C).

[0085] The present invention provides a preparation method of the high-temperature resistant organic fiber composite gasket material described in the above technical solutions, including the following steps:

[0086] Mix the first hybrid filler, the second hybrid filler, and the polyimide resin solution to obtain an impregnating solution;

[0087] Immerse the polyimide fiber-polytetrafluoroethylene fiber blended fiber fabric in the impregnating solution, and obtain a fabric prepreg after drying;

[0088] Cure the fabric prepreg to obtain the high-temperature resistant organic fiber composite gasket material.

[0089] In the present invention, the first hybrid filler, the second hybrid filler and the polyimide resin solution are mixed to obtain an impregnating solution.

[0090] In the present invention, the solvent of the polyimide resin solution is preferably N,N-dimethylacetamide and / or polyvinylpyrrolidone. When the solvent of the polyimide resin solution is preferably two of the above, the present invention has no special limitation on the ratio of different types of solvents, and any ratio is acceptable. In the present invention, the concentration of the polyimide resin solution is preferably 0.1 - 0.3 g / mL, and can be 0.15, 0.2, 0.25 or 0.3 g / mL. In the present invention, the mass percentage of the first hybrid filler and the second hybrid filler in the polyimide resin in the polyimide resin solution is the same as that in the above technical solution, and will not be elaborated here. The present invention has no special requirement for the method of mixing the first hybrid filler, the second hybrid filler and the polyimide resin solution, and it is only necessary to ensure that the components are mixed evenly.

[0091] After obtaining the impregnating solution, in the present invention, the polyimide fiber-polytetrafluoroethylene fiber blended fiber fabric is impregnated in the impregnating solution and dried to obtain a fabric prepreg.

[0092] Before the impregnation, in the present invention, it is preferably to perform plasma surface treatment on the polyimide fiber-polytetrafluoroethylene fiber blended fiber fabric. In the present invention, the plasma surface treatment is preferably carried out by an air plasma machine, the power is preferably 100 W, and the treatment time is preferably 10 min. In the present invention, the plasma surface treatment can improve the surface roughness and the content of active groups of the blended fiber fabric, so that a chemical bonding effect is generated between the blended fiber fabric and the polyimide resin matrix during the impregnation process, enhancing the interfacial bonding effect between the blended fiber fabric and the polyimide resin, thereby enhancing the friction performance of the organic fiber composite gasket material.

[0093] The present invention has no special requirement for the operation mode of the impregnation, and any impregnation mode well-known to those skilled in the art can be adopted. In the present invention, the drying is preferably baking; the present invention preferably repeats the operations of impregnation and drying until the mixture of the first hybrid filler, the second hybrid filler and the polyimide resin accounts for 15 - 40% (i.e., the sizing amount) of the mass of the fabric prepreg.

[0094] In the fabric prepreg, the first hybrid filler, the second hybrid filler and the polyimide resin are coated on the surface of the self-lubricating fabric as the continuous phase of the composite material.

[0095] After obtaining the fabric prepreg, in the present invention, the fabric prepreg is cured to obtain the high-temperature resistant organic fiber composite gasket material.

[0096] In the present invention, the curing pressure is preferably 0.01 to 3 MPa, and can be 0.2, 0.5, 1, 2 or 2.5 MPa. The curing is preferably carried out under constant pressure; the curing preferably adopts programmed heating, including a first stage, a second stage, a third stage and a fourth stage carried out in sequence; the temperature in the first stage is preferably 100 to 120 °C, and the heat preservation time is preferably 30 to 40 min; the temperature in the second stage is preferably 150 to 170 °C, and the heat preservation time is preferably 60 to 80 min; the temperature in the third stage is preferably 200 to 220 °C, and the heat preservation time is preferably 40 to 60 min; the temperature in the fourth stage is preferably 250 to 270 °C, and the heat preservation time is preferably 40 to 60 min; the heating rate in each stage is preferably 3 to 10 °C / min, and can be 5, 8 or 10 °C / min.

[0097] In order to facilitate the friction performance detection of the prepared high-temperature resistant organic fiber composite gasket material, before the curing, the present invention preferably uses a polyimide resin adhesive to paste the obtained fabric prepreg on the surface of a metal substrate, and then carries out curing; the metal substrate can be bearing steel, such as 9Cr18Mo, 9Cr18MoV, 9Cr18, 4Cr13 or 17-4PH. The present invention has no special limitation on the pasting process, and it can be carried out according to the process well-known in the art.

[0098] The present invention provides the application of the high-temperature resistant organic fiber composite gasket material described in the above technical solution or the high-temperature resistant organic fiber composite gasket material prepared by the preparation method described in the above technical solution in the friction field. In the present invention, the friction field includes many components such as aeroengines and aircraft landing gears. The present invention has no special limitation on the application method, and it can be applied according to the method well-known in the art.

[0099] In order to further illustrate the present invention, the following examples are used to describe in detail the composite filler, the high-temperature resistant organic fiber composite gasket material and their preparation methods and applications provided by the present invention, but they cannot be understood as a limitation to the protection scope of the present invention.

[0100] Example 1

[0101] Preparation of the filler, the method is as follows:

[0102] Disperse 0.2 g of sodium-based montmorillonite in 100 mL of deionized water, and heat and reflux with stirring at 70 °C for 4 h to ensure the stable dispersion of montmorillonite in water, obtaining a montmorillonite dispersion; subsequently, add 33 mL of cetyltrimethylammonium bromide (CTAB) ethanol solution with a dispersion concentration of 2 mg / mL in ethanol to the above montmorillonite dispersion; heat and reflux the obtained mixture with stirring at 70 °C for 4 h, cool, filter, wash the solid phase, and freeze-dry the mixture after the reaction to obtain organically modified montmorillonite nanosheets (OMMT).

[0103] Mix 50 mL of cobalt nitrate methanol solution (5 mg / mL) and 50 mL of 2-methylimidazole methanol solution (0.77 mg / mL). After the above solutions are mixed evenly, add 0.5 g of organically modified montmorillonite nanosheets to the above mixed solution and disperse it evenly by ultrasonic treatment; then transfer the obtained mixture to a hydrothermal reactor and carry out a solvothermal reaction at 90 °C for 25 h; after the hydrothermal reactor cools down with the furnace, filter, wash the solid phase, and freeze-dry the obtained mixture to obtain the first hybrid filler, namely the OMMT@Co-MOF hybrid.

[0104] Disperse 0.2 g of boron nitride nanosheets in 100 mL of Tris-HCl buffer solution (2 mg / mL, pH 8.5) and ultrasonically treat for 30 min to obtain a uniform dispersion of boron nitride nanosheets; then add 0.2 g of dopamine hydrochloride to the above dispersion, and then stir it open at room temperature for 24 h to complete the oxidative self-polymerization of dopamine hydrochloride on the surface of boron nitride nanosheets. After that, filter, wash the solid phase, and freeze-dry the obtained mixture to obtain polydopamine-modified boron nitride nanosheets.

[0105] Disperse the obtained polydopamine-modified boron nitride nanosheets in 100 mL of methanol and ultrasonically treat for 30 min to obtain a uniform dispersion. Then add 0.1 g of silver acetate to this dispersion and stir and react at room temperature for 10 h to complete the adsorption of silver ions on the surface of boron nitride nanosheets; after the reaction is completed, let the obtained mixture stand for 1 h to complete the precipitation of the mixture, pour off the supernatant, and add the same volume of methanol as the poured-off supernatant to the obtained precipitate. Then add 0.1 g of sodium dihydrogen phosphate and reflux and react at 60 °C for 5 h to complete the complete reduction of silver nanoparticles on the surface of boron nitride nanosheets. Finally, filter, wash the solid phase, and freeze-dry the obtained mixture to obtain the second hybrid filler, namely the BN@Ag hybrid.

[0106] The preparation of the high-temperature resistant organic fiber composite gasket material is as follows:

[0107] Using polytetrafluoroethylene fiber as the weft yarn and polyimide fiber as the warp yarn, a polyimide fiber-polytetrafluoroethylene fiber blended fiber fabric is woven by plain weave with a warp density of 400 threads / 10 cm and a weft density of 350 threads / 10 cm. The blended fiber fabric is cut into small pieces of 100 mm×100 mm, and the blended fiber fabric is treated by an air plasma machine for 10 min under the power condition of 100 W to obtain a plasma-treated blended fiber fabric.

[0108] 20 g of polyimide resin solution is dispersed in 100 mL of N,N-dimethylacetamide solvent to obtain a polyimide resin solution; the polyimide resin solution is mixed evenly with 0.2 g of OMMT@Co-MOF and 0.2 g of BN@Ag hybrid filler to obtain a polyimide resin impregnating solution.

[0109] The obtained plasma-treated blended fiber fabric is impregnated and dried in the impregnating solution to obtain a fabric prepreg. The impregnation-drying operation is repeated until the mass fraction of the polyimide resin and the OMMT@Co-MOF and BN@Ag hybrid mixture in the obtained fabric prepreg reaches 30%;

[0110] The fabric prepreg is pasted on the surface of a 17-4PH metal substrate with polyimide resin for curing. The curing pressure is set at 0.5 MPa, and the curing temperature program is: keep warm at 100 °C for 30 min, keep warm at 150 °C for 60 min, keep warm at 200 °C for 40 min, keep warm at 250 °C for 40 min, and the heating rate is 5 °C / min to obtain a high-temperature resistant organic fiber composite gasket material jointly reinforced by OMMT@Co-MOF and BN@Ag hybrids.

[0111] Example 2

[0112] 0.2 g of sodium montmorillonite is dispersed in 100 mL of deionized water and heated under reflux with stirring at 70 °C for 4 h to ensure the stable dispersion of montmorillonite in water, obtaining a montmorillonite dispersion; then 33 mL of CTAB ethanol solution with a dispersion concentration of 2 mg / mL of CTAB in ethanol is added dropwise to the above montmorillonite dispersion; the obtained mixed solution is heated under reflux with stirring at 70 °C for 4 h. After the reaction, the mixed solution is cooled, filtered, solid-phase washed, and freeze-dried to obtain organically modified montmorillonite nanosheets (OMMT).

[0113] Mix 50 mL of cobalt nitrate methanol solution (5 mg / mL) with 50 mL of 2-methylimidazole methanol solution (0.77 mg / mL). After the above solutions are mixed evenly, add 0.3 g of organically modified montmorillonite nanosheets to the above mixed solution and disperse them evenly by ultrasonic treatment. Then transfer the obtained mixed solution to a hydrothermal reactor and carry out a solvothermal reaction at 100 °C for 20 h. After the hydrothermal reactor cools down with the furnace, filter the obtained mixed solution, wash the solid phase, and freeze-dry it to obtain the OMMT@Co-MOF hybrid.

[0114] Disperse 0.2 g of boron nitride nanosheets in 100 mL of Tris-HCl buffer solution (2 mg / mL, pH 8.5) and ultrasonicate for 30 min to obtain a homogeneous dispersion of boron nitride nanosheets. Then add 0.2 g of dopamine hydrochloride to the above dispersion, and then stir it open at room temperature for 24 h to complete the oxidative self-polymerization of dopamine hydrochloride on the surface of boron nitride nanosheets. After that, filter the obtained mixed solution, wash the solid phase, and freeze-dry it to obtain polydopamine-modified boron nitride nanosheets.

[0115] Disperse the obtained polydopamine-modified boron nitride nanosheets in 100 mL of methanol and ultrasonicate for 30 min to obtain a homogeneous dispersion. Then add 0.1 g of silver acetate to the above solution and stir and react at room temperature for 10 h to complete the adsorption of silver ions on the surface of boron nitride nanosheets. After the reaction is completed, let the obtained mixed solution stand for 1 h to complete the precipitation of the mixed solution, pour off the supernatant, and add methanol with the same volume as the poured-off supernatant to the obtained precipitate. Then add 0.1 g of sodium dihydrogen phosphate to it and reflux and react at 60 °C for 5 h to complete the complete reduction of silver nanoparticles on the surface of boron nitride nanosheets. Finally, filter the obtained mixed solution, wash the solid phase, and freeze-dry it to obtain the BN@Ag hybrid.

[0116] Use polytetrafluoroethylene fiber as the weft yarn and polyimide fiber as the warp yarn, and weave a polyimide fiber-polytetrafluoroethylene fiber blended fiber fabric by plain weave according to a warp density of 400 yarns / 10 cm and a weft density of 350 yarns / 10 cm. Cut the blended fabric into small pieces of 100 mm × 100 mm, and treat the blended fiber fabric with an air plasma machine at a power of 100 W for 10 min to obtain a plasma-treated blended fiber fabric.

[0117] Disperse 20 g of polyimide resin adhesive solution in 100 mL of N,N-dimethylacetamide solvent to obtain a polyimide resin solution; mix the polyimide resin solution evenly with 0.2 g of OMMT@Co-MOF and 0.4 g of BN@Ag hybrid filler to obtain a polyimide resin impregnating solution.

[0118] The obtained plasma-treated blended fiber fabric is impregnated and dried in the said impregnating solution to obtain a fabric prepreg. The operations of impregnation and drying are repeated until the mass fraction of the polyimide resin and the mixture of OMMT@Co-MOF and BN@Ag hybrids in the obtained fabric prepreg reaches 30%;

[0119] The fabric prepreg is pasted on the surface of a 17-4PH metal substrate with polyimide resin for curing. The curing pressure is set at 0.5 MPa, and the curing temperature program is: holding at 100 °C for 30 min, holding at 150 °C for 60 min, holding at 200 °C for 40 min, holding at 250 °C for 40 min, and the heating rate is 5 °C / min, to obtain a high-temperature resistant organic fiber composite liner material jointly reinforced by OMMT@Co-MOF and BN@Ag hybrids.

[0120] Example 3

[0121] 0.2 g of sodium montmorillonite is dispersed in 100 mL of deionized water, and heated under reflux with stirring at 70 °C for 4 h to ensure the stable dispersion of montmorillonite in water, obtaining a montmorillonite dispersion; subsequently, 33 mL of a CTAB ethanol solution with a dispersion concentration of 2 mg / mL in ethanol is added dropwise to the above montmorillonite dispersion; the obtained mixture is heated under reflux with stirring at 70 °C for 4 h. After the reaction ends, the mixed solution is cooled, filtered, solid-phase washed, and freeze-dried to obtain organically modified montmorillonite nanosheets (OMMT).

[0122] 50 mL of a cobalt nitrate methanol solution (5 mg / mL) and 50 mL of a 2-methylimidazole methanol solution (0.77 mg / mL) are mixed. After the above solutions are mixed evenly, 0.5 g of organically modified montmorillonite nanosheets is added to the above mixed solution and ultrasonically dispersed evenly; then the obtained mixture is transferred to a hydrothermal autoclave and subjected to a solvothermal reaction at 90 °C for 25 h; after the hydrothermal autoclave is cooled with the furnace, the obtained mixture is filtered, solid-phase washed, and freeze-dried to obtain an OMMT@Co-MOF hybrid.

[0123] 0.2 g of boron nitride nanosheets is dispersed in 100 mL of a Tris-HCl buffer solution (2 mg / mL, pH 8.5), and ultrasonically treated for 30 min to obtain a uniform dispersion of boron nitride nanosheets; then 0.2 g of hydrochloric acid dopamine is added to the above dispersion, and then stirred open at room temperature for 24 h to complete the oxidative self-polymerization of hydrochloric acid dopamine on the surface of boron nitride nanosheets. After that, the obtained mixture is filtered, solid-phase washed, and freeze-dried to obtain polydopamine-modified boron nitride nanosheets.

[0124] The obtained polydopamine-modified boron nitride nanosheets were dispersed in 100 mL of methanol and sonicated for 30 min to obtain a uniform dispersion. Then, 0.1 g of silver acetate was added to the dispersion, and the mixture was stirred at room temperature for 10 h to complete the adsorption of silver ions on the surface of the boron nitride nanosheets. After the reaction was completed, the obtained mixture was allowed to stand for 1 h to complete the precipitation of the mixture. The supernatant was poured off, and methanol with the same volume as the poured-off supernatant was added to the obtained precipitate. Then, 0.1 g of sodium dihydrogen phosphate was added thereto, and the mixture was refluxed at 60 °C for 5 h to complete the complete reduction of silver nanoparticles on the surface of the boron nitride nanosheets. Finally, the obtained mixture was filtered, solid-phase washed, and freeze-dried to obtain the BN@Ag hybrid.

[0125] Using polytetrafluoroethylene fiber as the weft yarn and polyimide fiber as the warp yarn, a polyimide fiber-polytetrafluoroethylene fiber blended fiber fabric was woven by plain weave with a warp density of 400 ends / 10 cm and a weft density of 350 ends / 10 cm. The blended fiber fabric was cut into small pieces of 100 mm×100 mm, and the blended fiber fabric was treated by an air plasma machine at a power of 100 W for 10 min to obtain the plasma-treated blended fiber fabric.

[0126] 20 g of polyimide resin sizing was dispersed in 100 mL of N,N-dimethylacetamide solvent to obtain a polyimide resin solution; the polyimide resin solution was mixed uniformly with 0.3 g of OMMT@Co-MOF and 0.3 g of BN@Ag hybrid filler to obtain a polyimide resin impregnating solution.

[0127] The obtained plasma-treated blended fiber fabric was impregnated and dried in the impregnating solution to obtain a fabric prepreg. The impregnation-drying operation was repeated until the mass fraction of the polyimide resin and the OMMT@Co-MOF, BN@Ag hybrid mixture in the obtained fabric prepreg reached 15% to obtain a composite blended fabric prepreg;

[0128] The fabric prepreg was pasted on the surface of a 17-4PH metal substrate with polyimide resin for curing. The curing pressure was set to 0.5 MPa, and the curing temperature program was: holding at 100 °C for 30 min, holding at 150 °C for 60 min, holding at 200 °C for 40 min, holding at 250 °C for 40 min, and the heating rate was 5 °C / min to obtain a high-temperature resistant organic fiber composite liner material jointly reinforced by OMMT@Co-MOF and BN@Ag hybrid.

[0129] Example 4

[0130] Disperse 0.2 g of sodium-based montmorillonite in 100 mL of deionized water, and heat under reflux with stirring at 70 °C for 4 h to ensure the stable dispersion of montmorillonite in water, obtaining a montmorillonite dispersion; subsequently, add 33 mL of CTAB ethanol solution to the above montmorillonite dispersion, and the dispersion concentration of CTAB in ethanol is 2 mg / mL; heat the obtained mixture under reflux with stirring at 70 °C for 4 h. After the reaction, cool the mixture, filter, wash the solid phase, and freeze-dry to obtain organically modified montmorillonite nanosheets (OMMT).

[0131] Mix 50 mL of cobalt nitrate methanol solution (5 mg / mL) and 50 mL of 2-methylimidazole methanol solution (0.77 mg / mL). After the above solution is mixed evenly, add 0.4 g of organically modified montmorillonite nanosheets to the above mixed solution and disperse evenly by ultrasonic treatment; then transfer the obtained mixture to a hydrothermal reactor and carry out a solvothermal reaction at 90 °C for 25 h; after the hydrothermal reactor cools down with the furnace, filter the obtained mixture, wash the solid phase, and freeze-dry to obtain the OMMT@Co-MOF hybrid.

[0132] Disperse 0.2 g of boron nitride nanosheets in 100 mL of Tris-HCl buffer solution (2 mg / mL, pH 8.5), and ultrasonically treat for 30 min to obtain a uniform dispersion of boron nitride nanosheets; then add 0.2 g of dopamine hydrochloride to the above dispersion, and then stir it open at room temperature for 24 h to complete the oxidative self-polymerization of dopamine hydrochloride on the surface of boron nitride nanosheets. After that, filter the obtained mixture, wash the solid phase, and freeze-dry to obtain polydopamine-modified boron nitride nanosheets.

[0133] Disperse the obtained polydopamine-modified boron nitride nanosheets in 100 mL of methanol and ultrasonically treat for 30 min to obtain a uniform dispersion. Then add 0.1 g of silver acetate to the above solution and stir and react at room temperature for 10 h to complete the adsorption of silver ions on the surface of boron nitride nanosheets; after the reaction is completed, let the obtained mixture stand for 1 h to complete the precipitation of the mixture, pour off the supernatant, and add the same volume of methanol as the poured-off supernatant to the obtained precipitate. Then add 0.1 g of sodium dihydrogen phosphate to it and reflux and react at 80 °C for 3 h to complete the complete reduction of silver nanoparticles on the surface of boron nitride nanosheets. Finally, filter the obtained mixture, wash the solid phase, and freeze-dry to obtain the BN@Ag hybrid.

[0134] Using polytetrafluoroethylene fiber as the weft yarn and polyimide fiber as the warp yarn, with a warp density of 400 yarns per 10 cm and a weft density of 350 yarns per 10 cm, a polyimide fiber-polytetrafluoroethylene fiber blended fiber fabric is woven by plain weave. The blended fiber fabric is cut into small pieces of 100 mm×100 mm, and the blended fiber fabric is treated with an air plasma machine at a power of 100 W for 10 min to obtain a plasma-treated blended fiber fabric.

[0135] Disperse 20 g of polyimide resin solution in 100 mL of N,N-dimethylacetamide solvent to obtain a polyimide resin solution; mix the polyimide resin solution evenly with 0.3 g of OMMT@Co-MOF and 0.2 g of BN@Ag hybrid filler to obtain a polyimide resin impregnating solution.

[0136] Immerse and dry the obtained plasma-treated blended fiber fabric in the impregnating solution to obtain a fabric prepreg. The operation of immersion and drying is repeated until the mass fraction of the polyimide resin and the OMMT@Co-MOF and BN@Ag hybrid mixture in the obtained fabric prepreg reaches 20%;

[0137] Paste the fabric prepreg on the surface of a 17-4PH metal substrate with polyimide resin for curing. The curing pressure is set at 0.5 MPa, and the curing temperature program is: keep warm at 100 °C for 30 min, keep warm at 150 °C for 60 min, keep warm at 200 °C for 40 min, keep warm at 250 °C for 40 min, and the heating rate is 5 °C / min to obtain a high-temperature resistant organic fiber composite liner material reinforced by OMMT@Co-MOF and BN@Ag hybrids.

[0138] Comparative Example 1

[0139] The difference from Example 1 is only that: the preparation process of the OMMT@Co-MOF hybrid filler and the mixing process of the OMMT@Co-MOF hybrid filler with the polyimide resin solution are omitted, and an organic fiber composite liner material reinforced only by the BN@Ag hybrid is prepared.

[0140] Comparative Example 2

[0141] The difference from Example 1 is only that: the preparation process of the BN@Ag hybrid filler and the mixing process of the BN@Ag hybrid filler with the polyimide resin solution are omitted, and an organic fiber composite liner material reinforced only by the OMMT@Co-MOF hybrid is prepared.

[0142] Comparative Example 3

[0143] The difference from Example 1 is only that: the preparation process of the OMMT@Co-MOF and BN@Ag hybrid fillers and the process of mixing the OMMT@Co-MOF and BN@Ag hybrid fillers with the polyimide resin solution are omitted, and an organic fiber composite gasket material without added fillers is prepared.

[0144] Performance test

[0145] (1) The friction and wear performance tests were respectively carried out on the high-temperature resistant organic fiber composite gasket materials jointly reinforced by OMMT@Co-MOF and BN@Ag hybrids prepared in Examples 1 to 4 and the organic fiber composite gasket materials prepared in Comparative Examples 1 to 3. The test method is as follows:

[0146] The test conditions were: load 50 MPa, sliding friction linear velocity 0.26 m / s, time 120 min, temperature 350 °C. The Xuanwu III friction and wear testing machine was used, and 45 steel with a diameter of 2 mm was used as the friction pair. After the data collected was processed by the connected computer, the friction coefficient was automatically output. The wear depth of the organic fiber composite gasket material was measured using a digital display height gauge, and then the wear volume of the fabric gasket was calculated. The specific wear rate of the fabric gasket material was calculated using the formula K = ΔV / P·L. The friction coefficient was automatically derived by the instrument, where K - specific wear rate (i.e., the wear rate in Table 1); ΔV - wear volume; P - applied load; L - sliding distance.

[0147] The test results are shown in Table 1.

[0148] Table 1 Friction and wear data of the organic fiber composite gasket materials prepared in the examples and comparative examples

[0149]

[0150] As can be seen from Table 1, the wear rate of the high-temperature resistant organic fiber composite gasket material jointly reinforced by OMMT@Co-MOF and BN@Ag hybrids prepared in Example 1 is 0.89×10 -14 m 3 (Nm) -1 , and the friction coefficient is 0.0377; while the organic fiber composite gasket material without added hybrid fillers in Comparative Example 3 could not run the full course stably and had been worn through. Compared with Comparative Example 3, after adding the OMMT@Co-MOF and BN@Ag hybrid fillers, the high-temperature wear resistance and lubrication performance of the organic fiber composite gasket material were significantly improved. Figure 1 It is the wear rate and friction coefficient diagram of the high-temperature resistant organic fiber composite gasket materials prepared in Comparative Example 3 and Example 1. Figure 1 Among them, (a) is the friction coefficient diagram, and (b) is the wear rate diagram.

[0151] (2) The morphologies after wear of Example 1 and Comparative Example 3 were characterized, and the results are shown in Figure 2 , where (a) is the morphology photo of the sample after wear in Example 1, and (b) is the morphology photo of the sample after wear in Comparative Example 3.

[0152] It can be seen from Figure 2 that the introduction of OMMT@Co-MOF and BN@Ag hybrid fillers greatly improves the tribological properties of the organic fiber composite gasket material, and a smooth wear scar is uniformly formed at the rubbing position of the gasket, showing excellent high-temperature wear resistance and lubrication performance.

[0153] The above is only the preferred embodiment of the present invention and does not impose any form of limitation on the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A composite filler, characterized in that: including a first hybrid filler and a second hybrid filler; The first hybrid filler includes montmorillonite nanosheets and Co-MOF nanoflowers grown on the surface of the montmorillonite nanosheets, wherein the montmorillonite nanosheets are obtained by intercalating montmorillonite with hexadecyltrimethylammonium bromide, and the Co-MOF nanoflowers are coordinated by cobalt ions and 2-methylimidazole; The second hybrid filler comprises polydopamine-modified boron nitride nanosheets and silver nanoparticles in-situ loaded on the surface of the polydopamine-modified boron nitride nanosheets; The mass ratio of the first hybrid filler to the second hybrid filler is (0.5-2):(0.5-2).

2. The composite filler according to claim 1, characterized in that: The method for preparing the first hybrid filler comprises the following steps: Montmorillonite is intercalated and modified by using hexadecyltrimethylammonium bromide to obtain organic modified montmorillonite; The organic modified montmorillonite is mixed with cobalt nitrate, 2-methylimidazole and an organic solvent to carry out a solvothermal reaction to obtain the first hybrid filler.

3. The composite filler according to claim 2, characterized in that: The mass ratio of the montmorillonite to hexadecyltrimethylammonium bromide is 1:(0.2-0.5), the temperature of the intercalation modification is 60-90°C, and the time is 2-5 hours; the mass ratio of the cobalt nitrate to 2-methylimidazole is 6.5:1, the mass ratio of the organic modified montmorillonite to cobalt nitrate is 1:(0.5-0.8), the temperature of the solvent thermal reaction is 80-100°C, and the time is 20-30 hours.

4. The composite filler according to claim 1, characterized in that: The preparation method of the second hybrid filler comprises the following steps: Boron nitride nanosheets, Tris-HCl buffer solution and dopamine hydrochloride are mixed for oxidative self-polymerization to obtain polydopamine-modified boron nitride nanosheets; The polydopamine-modified boron nitride nanosheets are mixed with an organic solvent and silver acetate to perform an adsorption reaction to obtain polydopamine-modified boron nitride nanosheets adsorbed with silver ions; The polydopamine-modified boron nitride nanosheets adsorbed with silver ions are in-situ reduced by sodium dihydrogen phosphate to obtain the second hybrid filler.

5. The composite filler according to claim 4, characterized in that: The mass ratio of the polydopamine-modified boron nitride nanosheets to silver acetate is (2-4):1; the mass ratio of the sodium dihydrogen phosphate to silver acetate is 1:1; the temperature of the adsorption reaction is room temperature, and the time is 8-12 hours; the temperature of the in-situ reduction is 60-80°C, and the time is 3-5 hours.

6. Use of the composite filler according to any one of claims 1 to 5 in the preparation of high temperature resistant organic fiber composite lining materials.

7. A high temperature resistant organic fiber composite lining material, characterized in that: It comprises a polyimide fiber-polytetrafluoroethylene fiber blended fiber fabric and a polyimide resin composite material composited on the blended fiber fabric; the polyimide resin composite material comprises a polyimide resin and a reinforcing filler dispersed in the polyimide resin, and the reinforcing filler is the composite filler according to any one of claims 1 to 5.

8. The high temperature resistant organic fiber composite lining material according to claim 7, characterized in that: The mass fraction of the polyimide resin composite material in the high temperature resistant organic fiber composite liner material is 15-40%, and the masses of the first hybrid filler and the second hybrid filler in the polyimide resin composite material are respectively 0.5-2% of the mass of the polyimide resin.

9. The method for preparing the high temperature resistant organic fiber composite liner material according to claim 7 or 8, characterized in that: The following steps are involved: Mixing the first hybrid filler, the second hybrid filler and the polyimide resin solution to obtain an impregnation solution; impregnating a polyimide fiber-polytetrafluoroethylene fiber blended fiber fabric in the impregnation solution, and drying to obtain a fabric prepreg; The fabric prepreg is cured to obtain the high temperature resistant organic fiber composite liner material.

10. Use of the high temperature resistant organic fiber composite gasket material according to claim 7 or 8 or the high temperature resistant organic fiber composite gasket material prepared by the preparation method according to claim 9 in the field of friction.

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