Bnn@ag hybrid filler, nanometer reinforcing filler of different dimensions and self-lubricating fabric liner material, preparation and application thereof

Abstract

The application provides a BNNs@Ag hybrid filler, a nano-enhanced filler of different dimensions and a self-lubricating fabric liner material, and preparation and application thereof, and relates to the technical field of solid lubrication.The application provides a preparation method of the BNNs@Ag hybrid filler, wherein silver nanoparticles are in-situ loaded on the surface of boron nitride nanosheets through in-situ reduction, the silver nanoparticles and the boron nitride nanosheets are integrated to highlight the lubricating performance, and the agglomeration effect of the silver nanoparticles is effectively relieved.The application provides a nano-enhanced filler of different dimensions, which comprises aramid nanofibers and the BNNs@Ag hybrid filler.The nano-enhanced filler of different dimensions is introduced into the self-lubricating fabric liner material, the excellent performance of the aramid nanofiber (one-dimensional) and the BNNs@Ag hybrid filler (two-dimensional and zero-dimensional) is exerted, the synergistic enhancement of the nano-enhanced filler of different dimensions on the tribological performance of the self-lubricating fabric liner material is completed, and the wear resistance and the lubricating performance are effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solid lubrication, and in particular to a BNNs@Ag hybrid filler, a nano-enhanced filler of different dimensions, a self-lubricating fabric liner material, and preparation and application thereof. BACKGROUND

[0002] The friction and wear performance of the self-lubricating fabric liner is a key factor to ensure that the joint bearing has the characteristics of self-lubrication, impact resistance, and long service life. However, when facing extreme application conditions such as heavy load and high temperature, the self-lubricating fabric liner may have phenomena such as resin shedding, fiber pulling out, and a decrease in the bonding force between the transfer film and the counterpart, thereby causing lubrication failure of the fabric liner material, which seriously affects the application range and service life of the joint bearing. Previous studies have found that the introduction of nano-enhanced fillers into the fabric liner material can effectively improve the load-carrying and temperature resistance of the fabric liner material, thereby improving the tribological performance of the fabric liner material.

[0003] The nano-enhanced fillers of different dimensions have different reinforcing effects in the friction process due to their different appearances. Aramid nanofibers (ANFs, one-dimensional nanomaterials) are nanofibers with a diameter of tens to hundreds of nanometers and a length of several to tens of micrometers prepared by processing aramid fibers. ANFs not only retain the chemical composition and crystal structure of aramid fibers, but also have a large specific surface area and aspect ratio, so they can be compounded with other materials. Two-dimensional boron nitride nanosheets have high thermal conductivity, low expansion coefficient, good high-temperature thermal insulation, good chemical stability, and excellent lubrication performance, and are therefore widely used as additives in lubricating materials. In addition, metal nanoparticles as lubricating additives can deposit on the friction surface to form a deposition film to improve the tribological performance, such as wear resistance, friction reduction, and load-carrying capacity; in addition, the special repair effect of metal nanoparticles fills the micro-pits on the worn surface. Among them, silver nanoparticles have good self-lubrication performance at room temperature, and their hardness is relatively low, which has a certain self-repairing effect. However, silver nanoparticles are prone to agglomeration due to their surface energy effect, which limits the reinforcing effect of silver nanoparticles. SUMMARY

[0004] Therefore, the present application provides a BNNs@Ag hybrid filler, a nano-enhanced filler of different dimensions, a self-lubricating fabric liner material, and preparation and application thereof. The BNNs@Ag hybrid filler prepared by the present application alleviates the agglomeration effect of silver nanoparticles and forms a nano-enhanced filler of different dimensions with aramid nanofibers, which can achieve a synergistic reinforcing effect on the tribological performance of the fabric liner material.

[0005] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0006] The application provides a preparation method of a BNNs@Ag hybrid filler, which comprises the following steps.

[0007] The boron nitride nanosheets are mixed with an organic solvent for ultrasonic exfoliation, and the obtained dispersion liquid is mixed with polyvinylpyrrolidone and silver nitrate for in-situ reduction to obtain the BNNs@Ag hybrid filler.

[0008] Preferably, the organic solvent is N,N-dimethylformamide, the concentration of the boron nitride nanosheets in the organic solvent is 5-10 mg / mL, and the ultrasonic exfoliation time is 10-30 min.

[0009] Preferably, the concentration of the polyvinylpyrrolidone in the dispersion liquid is 1-3 mg / mL, the mass ratio of the silver nitrate to the boron nitride nanosheets is 1:2-4, the in-situ reduction temperature is 50-70 ℃, and the in-situ reduction time is 1.5-2.5 h.

[0010] The application provides a BNNs@Ag hybrid filler prepared by the preparation method.

[0011] The application provides a different-dimension nano-enhanced filler, which comprises aramid nanofibers and a BNNs@Ag hybrid filler.

[0012] The application provides an application of the different-dimension nano-enhanced filler in a self-lubricating fabric lining material.

[0013] The application provides a self-lubricating fabric lining material, which comprises a self-lubricating fiber fabric and a phenolic resin composite material compounded on the self-lubricating fiber fabric.

[0014] Preferably, the self-lubricating fiber fabric is a meta-aramid fiber-polytetrafluoroethylene fiber blended fabric, the mass fraction of the phenolic resin composite material in the self-lubricating fabric lining material is 15-40%, and the mass of the aramid nanofibers and the BNNs@Ag hybrid filler in the phenolic resin composite material is 0.5-2% and 0.5-2% of the mass of the phenolic resin, respectively.

[0015] The application provides a preparation method of the self-lubricating fabric lining material.

[0016] mixing the different dimensional nanometer reinforced fillers with a phenolic resin solution to obtain an impregnation solution;

[0017] impregnating the self-lubricating fabric in the impregnation solution to obtain a fabric prepreg after drying;

[0018] curing the fabric prepreg to obtain the self-lubricating fabric gasket material.

[0019] The application provides application of the self-lubricating fabric gasket material in a self-lubricating joint bearing.

[0020] The application provides a preparation method of a BNNs@Ag hybrid filler, which comprises the following steps: mixing boron nitride nanosheets with an organic solvent for ultrasonic exfoliation, mixing the obtained dispersion liquid with polyvinylpyrrolidone and silver nitrate for in-situ reduction to obtain the BNNs@Ag hybrid filler.

[0021] The application provides different dimensional nanometer reinforced fillers, which comprise aramid nanofibers and the BNNs@Ag hybrid filler, wherein the BNNs@Ag hybrid filler is the BNNs@Ag hybrid filler in the above technical solution; and the mass ratio of the aramid nanofiber and the BNNs@Ag hybrid filler is (0.5-2):(0.5-2). BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The wear rate and friction coefficient of the self-lubricating fabric gasket material prepared in Comparative Example 1 and Example 2 are shown in the figure, Figure 1 (a) is a friction coefficient figure, and (b) is a wear rate figure;

[0023] Figure 2 The morphology of the aramid nanofiber and the BNNs@Ag hybrid in Example 1 is shown in the figure, Figure 2In the figure, (a), (c) are scanning, transmission pictures of aramid nanofiber respectively; (b), (d) are scanning, transmission pictures of BNNs@Ag hybrid respectively. DETAILED DESCRIPTION

[0024] The application provides a preparation method of BNNs@Ag hybrid filler, comprising the following steps:

[0025] The boron nitride nanosheet is mixed with an organic solvent for ultrasonic exfoliation, and the obtained dispersion liquid is mixed with polyvinylpyrrolidone and silver nitrate for in-situ reduction to obtain the BNNs@Ag hybrid filler.

[0026] The application does not have special requirements for the boron nitride nanosheet (BNNs), and the boron nitride nanosheet known to those skilled in the art can be used.

[0027] In the application, the organic solvent is preferably N,N-dimethylformamide, and the concentration of the boron nitride nanosheet in the organic solvent is preferably 5-10 mg / mL, and more preferably 5-8 mg / mL. In the application, the time for ultrasonic exfoliation is preferably 10-30 min, and more preferably 20-30 min; the boron nitride nanosheet is exfoliated into a few layers (≤5 layers) by the ultrasonic exfoliation.

[0028] In the application, the concentration of the polyvinylpyrrolidone in the dispersion liquid is preferably 1-3 mg / mL, and more preferably 2 mg / mL, and the polyvinylpyrrolidone acts as a polymer surfactant and a reducing agent for silver ions. In the application, the mass ratio of the silver nitrate to the boron nitride nanosheet is preferably 1:2-4, and more preferably 1:3. The application preferably adds the polyvinylpyrrolidone in the dispersion liquid, uniformly disperses after stirring, and then adds silver nitrate; the silver nitrate is preferably added in the form of an aqueous silver nitrate solution.

[0029] In the application, the temperature for in-situ reduction is preferably 50-70℃, and more preferably 60℃, and the time is preferably 1.5-2.5 h, and more preferably 2 h; the temperature for in-situ reduction is preferably achieved by water bath heating, and the time for in-situ reduction is calculated from the completion of the addition of silver nitrate; the in-situ reduction is preferably carried out under stirring.

[0030] After the in-situ reduction is completed, the application preferably sequentially performs centrifugal washing and freeze-drying on the obtained reaction liquid to obtain the BNNs@Ag hybrid filler.

[0031] Two-dimensional hexagonal boron nitride nanosheets have excellent biocompatibility, mechanical strength, high-temperature oxidation resistance and chemical stability, similar to graphene structure. In addition, similar to most two-dimensional layered materials, two-dimensional hexagonal boron nitride nanosheets have excellent lubricating properties. At the same time, two-dimensional hexagonal boron nitride nanosheets can be used as a base material, and other materials can be further loaded on the surface of the two-dimensional hexagonal boron nitride nanosheets to play the excellent performance of different materials. Considering the good self-lubricating performance of silver nanoparticles and the easy agglomeration characteristics of the silver nanoparticles, the present application reduces silver nitrate in situ by using polyvinylpyrrolidone as a reducing agent, reduces silver nanoparticles in situ and loads silver nanoparticles on the surface of boron nitride nanosheets, which effectively relieves the agglomeration effect of silver nanoparticles while integrating the outstanding lubricating performance of silver nanoparticles and boron nitride nanosheets.

[0032] The present application provides a BNNs@Ag hybrid filler prepared by the preparation method described in the above technical solution, which comprises boron nitride nanosheets and silver nanoparticles loaded in situ on the surface of the boron nitride nanosheets. The BNNs@Ag hybrid filler provided by the present application integrates the outstanding lubricating performance of two-dimensional boron nitride nanosheets and zero-dimensional silver nanoparticles.

[0033] The present application provides a different dimension nanometer reinforced filler, which comprises aramid nanofibers and a BNNs@Ag hybrid filler, wherein the BNNs@Ag hybrid filler is the BNNs@Ag hybrid filler described in the above technical solution; and the mass ratio of the aramid nanofibers and the BNNs@Ag hybrid filler is (0.5-2):(0.5-2).

[0034] The present application does not have special requirements for the source of the aramid nanofibers, and aramid nanofibers known to those skilled in the art can be used. In the embodiments of the present application, the aramid nanofibers are preferably prepared by the following method:

[0035] The aramid fibers, potassium hydroxide and dimethyl sulfoxide-water mixed solvent are mixed, and the reaction is carried out under stirring. The obtained reaction liquid is diluted, filtered, washed and dried to obtain aramid nanofibers.

[0036] In the present application, the aramid fiber is preferably para-aramid fiber filament (Kevlar fiber), which is cut into short fibers by using an electric scissors before use, facilitating the subsequent reaction. In the present application, the mass ratio of the aramid fiber to potassium hydroxide is preferably 1:1.5; the volume ratio of dimethyl sulfoxide (DMSO) to water in the mixed solvent of dimethyl sulfoxide-water is preferably 20-30:1, more preferably 20-25:1; and the concentration of the aramid fiber in the mixed solvent is preferably 1-4 mg / mL, more preferably 2-3 mg / mL. In the present application, potassium hydroxide is dissolved in water, the obtained potassium hydroxide solution is added to dimethyl sulfoxide, and then the aramid fiber is added to the obtained mixture. In the present application, the reaction temperature is preferably 40°C, and the reaction time is preferably 4-10 h, and a homogeneous, dispersed and stable dispersion liquid is obtained after the reaction. The operation method for dilution, filtration, washing and drying in the present application is not particularly limited, and the operation method known in the art can be used, wherein the washing is preferably water washing, and aramid nanofibers are precipitated during the washing. In the present application, the aramid fiber is dissolved to a certain extent by using a mixed solution of alkali and organic solvent, and one-dimensional aramid nanofibers are obtained by re-precipitation.

[0037] In the present application, the potassium hydroxide / dimethyl sulfoxide strong base system can effectively destroy the hydrogen bond crosslinking between the molecular chains of macroscopic aramid fibers, and at the same time, the N-H bond on the amide bond is broken to form a nitrogen negative ion, the negatively charged molecular chains are dispersed and stably exist under the action of electrostatic repulsion, π-π conjugation force generated by benzene ring and amide bond and intermolecular van der Waals force, and one-dimensional aramid nanofibers with unique nanoscale structure, large aspect ratio and specific surface area are obtained, while the excellent mechanical properties and temperature resistance of aramid macroscopic fibers are retained, which brings mechanical properties that cannot be achieved by conventional chemical fibers.

[0038] In the present application, the mass ratio of the aramid nanofiber to the BNNs@Ag hybrid filler is (0.5-2):(0.5-2), preferably (0.5-1):(0.5-1). The different dimensional nanoreinforced fillers provided in the present application are a mixture of aramid nanofibers and BNNs@Ag hybrid fillers. In the examples of the present application, the different dimensional nanoreinforced fillers are referred to as aramid nanofiber-BNNs@Ag hybrid fillers.

[0039] The application provides application of the different-dimension nano-enhanced filler in the self-lubricating fabric liner material.

[0040] The application provides a self-lubricating fabric liner material, which comprises a self-lubricating fiber fabric and a phenolic resin composite material compounded on the self-lubricating fiber fabric; the phenolic resin composite material comprises a phenolic resin and an enhanced filler dispersed in the phenolic resin, and the enhanced filler is the different-dimension nano-enhanced filler in the above technical solution.

[0041] In the application, the self-lubricating fiber fabric is preferably meta-aramid fiber-polytetrafluoroethylene fiber blended fabric; the meta-aramid fiber-polytetrafluoroethylene fiber blended fabric is preferably woven with polytetrafluoroethylene fiber as weft and meta-aramid fiber as warp, and in the embodiment of the application, the fineness of the polytetrafluoroethylene fiber is specifically 400D, and the fineness of the meta-aramid fiber is specifically 200D. In the application, the weave structure of the meta-aramid fiber-polytetrafluoroethylene fiber blended fabric is preferably one or several of plain weave, twill weave and satin weave; when the weave structure of the meta-aramid fiber-polytetrafluoroethylene fiber blended fabric is several of the above, the application does not have special limitation on the distribution ratio and mode of different weave structures, and any ratio or mode can be adopted. In the application, the warp density of the meta-aramid fiber-polytetrafluoroethylene fiber blended fabric is preferably 320-490 per 10 cm, and the weft density is preferably 290-350 per 10 cm. The application does not have special limitation on the specific process of weaving, and the above warp density and weft density can be adopted according to the process well known in the art.

[0042] In the application, the mass fraction of the phenolic resin composite material in the self-lubricating fabric liner material is preferably 15-40%, and more preferably 20-30%; the mass of the aramid nanofiber and the BNNs@Ag hybrid filler in the phenolic resin composite material is preferably 0.5-2% and 0.5-2% of the mass of the phenolic resin, respectively, and more preferably 0.5-1% and 0.5-1%, respectively. The application does not have special requirement on the phenolic resin, and the phenolic resin well known by those skilled in the art can be adopted.

[0043] The application provides a preparation method of the self-lubricating fabric gasket material, and comprises the following steps:

[0044] The different-dimension nano-reinforced fillers are mixed with a phenolic resin solution to obtain an impregnation solution.

[0045] The self-lubricating fabric is impregnated in the impregnation solution, and a fabric prepreg is obtained through drying.

[0046] The fabric prepreg is cured to obtain the self-lubricating fabric gasket material.

[0047] In the application, the solvent of the phenolic resin solution is preferably at least two of ethanol, acetone and ethyl acetate, and the application does not have special limitations on the ratio of different kinds of solvents, and any ratio is acceptable. In the application, the mass concentration of the phenolic resin solution is preferably 0.1-0.3 g / mL, and more preferably 0.15-0.25 g / mL. In the application, the different-dimension nano-reinforced fillers are mixed with the phenolic resin solution, that is, aramid nanofibers and BNNs@Ag hybrid filler are mixed with the phenolic resin solution, and the application does not have special requirements for the mixing method, as long as the components are uniformly mixed. In the application, the mass percentage of the aramid nanofibers and the BNNs@Ag hybrid filler in the phenolic resin in the phenolic resin solution is the same as that in the above technical solution, and will not be described here.

[0048] After obtaining the impregnation solution, the self-lubricating fabric is impregnated in the impregnation solution, and a fabric prepreg is obtained through drying. Before impregnation, the self-lubricating fabric is preferably subjected to air plasma treatment; the power of the air plasma treatment is preferably 40-300 W, and more preferably 100-250 W, and the treatment time is preferably 5-30 min, and more preferably 10-20 min. The application etches the fiber surface of the self-lubricating fabric through air plasma treatment, breaks the molecular chain on the fiber surface, introduces active functional groups on the fiber surface, so that the self-lubricating fabric and the phenolic resin matrix produce a chemical bonding effect during the impregnation process, enhances the interfacial bonding effect between the self-lubricating fabric and the phenolic resin, and thus enhances the friction performance of the self-lubricating fabric gasket material.

[0049] The present application does not have special requirements for the operation mode of the impregnation, and the impregnation mode well known to those skilled in the art can be used. In the present application, the drying is preferably baking; the present application preferably repeats the operation of impregnation and drying until the mixture of the different-dimension nano-reinforced filler and the phenolic resin accounts for 15-40% of the mass of the fabric prepreg (i.e., the sizing amount). In the fabric prepreg, the different-dimension nano-reinforced filler and the phenolic resin are coated on the surface of the self-lubricating fabric as the continuous phase of the composite material.

[0050] After obtaining the fabric prepreg, the present application cures the fabric prepreg to obtain the self-lubricating fabric lining material. In the present application, the curing pressure is preferably 0.01-3 MPa, more preferably 0.2-2.5 MPa; the curing temperature is preferably 150-250°C, more preferably 180-200°C, and further preferably 185-190°C; the curing holding time is preferably 0.5-3 h, more preferably 1-2.2 h, and further preferably 1.5-2 h; and the temperature rising rate to the curing temperature is preferably 3-10°C / min, and more preferably 5-8°C / min.

[0051] In order to facilitate the friction performance detection of the prepared self-lubricating fabric lining material, before the curing reaction, the present application preferably uses a phenolic resin adhesive to paste the obtained fabric prepreg on the surface of a metal substrate, and then cures. The metal substrate is preferably bearing steel, and more preferably 9Cr18Mo, 9Cr18MoV, 9Cr18, 4Cr13 or 17-4PH. The present application does not have special limitations on the pasting process, and the process well known in the art can be used.

[0052] The present application provides the application of the self-lubricating fabric lining material in the above technical solution or the self-lubricating fabric lining material prepared by the preparation method in the above technical solution in a self-lubricating knuckle bearing. The present application does not have special limitations on the application method, and the method well known in the art can be used.

[0053] In order to further illustrate the present application, the BNNs@Ag hybrid filler, the different-dimension nano-reinforced filler, the self-lubricating fabric lining material, and the preparation and application provided by the present application are described in detail below with reference to examples, but they should not be understood as limitations on the protection scope of the present application.

[0054] Example 1

[0055] Dissolve 1.5 g of KOH in 20 mL of deionized water, then add the above KOH solution to 480 mL of DMSO solvent, and stir to disperse uniformly. Disperse 1 g of aramid fiber in the above mixed solution, and stir to react at 40°C for 4 h. Then dilute, filter, wash, and dry the above mixed solution to obtain aramid nanofiber.

[0056] Disperse 0.8 g of BNNs (boron nitride nanosheet) in 100 mL of N,N-dimethylformamide solution, and ultrasonically disperse for 30 min to further ultrasonically exfoliate the boron nitride nanosheet. Add 0.2 g of polyvinylpyrrolidone to the solution, stir to disperse uniformly, and then further add 0.27 g of silver nitrate to the mixed solution, and stir to react at 60°C for 2 h. Finally, centrifugally wash and freeze-dry the above mixed solution to obtain BNNs@Ag hybrid filler.

[0057] Disperse 10 g of phenolic resin glue solution in 70 mL of a mixed solvent of ethanol-ethyl acetate-acetone, with a volume ratio of ethanol, ethyl acetate, and acetone being 1:1:1, to obtain a phenolic resin solution. Mix the phenolic resin solution with 0.1 g of aramid nanofiber and 0.1 g of BNNs@Ag hybrid, with the mass fraction of aramid nanofiber and BNNs@Ag hybrid in the phenolic resin being 1 wt% and 1 wt% respectively, to obtain a resin impregnation solution.

[0058] Use polytetrafluoroethylene fiber as weft yarn and meta-aramid fiber as warp yarn, and weave a meta-aramid fiber-polytetrafluoroethylene fiber blended fabric according to a warp density of 400 yarns / 10 cm and a weft density of 350 yarns / 10 cm, and perform air plasma modification treatment on the blended fabric at 100 W for 10 min. Repeat the impregnation-drying of the obtained blended fabric in the impregnation solution until the mass fraction of the mixture of phenolic resin and aramid nanofiber-BNNs@Ag hybrid in the obtained composite blended fabric prepreg reaches 30%, to obtain a composite blended fabric prepreg.

[0059] Paste the composite blended fabric prepreg with phenolic resin on the surface of a 17-4PH metal substrate, and heat at a heating rate of 5°C / min to 185°C, and cure at 0.3 MPa for 2 h, to obtain an aramid nanofiber-BNNs@Ag hybrid reinforced self-lubricating fabric gasket material.

[0060] Example 2

[0061] Dissolve 1.5 g of KOH in 20 mL of deionized water, then add the above KOH solution to 480 mL of DMSO solvent, and stir to disperse uniformly. Disperse 1 g of aramid fiber in the above mixed solution, and stir to react at 40°C for 4 h. Then dilute, filter, wash, and dry the above mixed solution to obtain aramid nanofiber.

[0062] 0.8 g of BNNs (boron nitride nanosheets) was dispersed in 100 mL of N,N- dimethylformamide solution, ultrasonic dispersion for 30 min, and the boron nitride nanosheets were further ultrasonic exfoliation; 0.2 g of polyvinylpyrrolidone was added to the solution, and after stirring and dispersing uniformly; further 0.27 g of silver nitrate was added to the mixed solution, and stirred at 60°C for 2 h; finally, the above mixed solution was washed by centrifugation, freeze-drying to obtain BNNs@Ag hybrid filler.

[0063] 10 g of phenolic resin glue solution was dispersed in 70 mL of ethanol-ethyl acetate- acetone mixed solvent, the volume ratio of ethanol, ethyl acetate and acetone was 1:1:1, to obtain a phenolic resin solution; the phenolic resin solution was mixed with 0.05 g of aramid nanofiber and 0.1 g of BNNs@Ag hybrid, the mass fraction of aramid nanofiber and BNNs@Ag hybrid in the phenolic resin was 0.5wt% and 1wt% respectively, to obtain a resin impregnation solution.

[0064] The meta-aramid fiber-polytetrafluoroethylene fiber blended fabric was obtained by using polytetrafluoroethylene fiber as weft and meta-aramid fiber as warp, with warp density of 400 threads / 10 cm and weft density of 350 threads / 10 cm, and air plasma modification treatment was carried out at 100 W for 10 min. The obtained blended fabric was repeatedly immersed and dried in the impregnation solution until the mass fraction of phenolic resin and aramid nanofiber-BNNs@Ag hybrid mixture in the obtained composite blended fabric prepreg reached 30%, to obtain a composite blended fabric prepreg.

[0065] The composite blended fabric prepreg was pasted on the surface of 17-4PH metal substrate with phenolic resin, and the temperature was raised to 185°C at a rate of 5°C / min, and cured at 0.3 MPa for 2 h, to obtain an aramid nanofiber-BNNs@Ag hybrid reinforced self-lubricating fabric liner material.

[0066] Example 3

[0067] 1.5 g of KOH was dissolved in 20 mL of deionized water, and then the above KOH solution was added to 480 mL of DMSO solvent and stirred and dispersed uniformly. 1 g of aramid fiber was dispersed in the above mixed solution, and stirred at 40°C for 4 h. Then the above mixed solution was diluted, filtered, washed and dried to obtain aramid nanofiber.

[0068] 0.6 g of BNNs (boron nitride nanosheets) was dispersed in 100 mL of N,N- dimethylformamide solution, ultrasonic dispersion for 30 min, and the boron nitride nanosheets were further ultrasonic exfoliation; 0.2 g of polyvinylpyrrolidone was added to the solution, and after stirring and dispersing uniformly; further 0.2 g of silver nitrate was added to the mixed solution, and stirred at 60°C for 2 h; finally, the above mixed solution was washed by centrifugation, freeze-drying to obtain BNNs@Ag hybrid filler.

[0069] 10 g of phenolic resin glue solution was dispersed in 70 mL of ethanol-ethyl acetate- acetone mixed solvent, the volume ratio of ethanol, ethyl acetate and acetone was 1:1:1, to obtain a phenolic resin solution; the phenolic resin solution was mixed with 0.1 g of aramid nanofiber and 0.05 g of BNNs@Ag hybrid, the mass fraction of aramid nanofiber and BNNs@Ag hybrid in the phenolic resin was 1wt% and 0.5wt% respectively, to obtain a resin impregnation solution.

[0070] The meta-aramid fiber-polytetrafluoroethylene fiber blended fabric was obtained by using polytetrafluoroethylene fiber as weft and meta-aramid fiber as warp, with warp density of 400 threads / 10 cm and weft density of 350 threads / 10 cm, and then treated by air plasma modification for 10 min at 100 W. The obtained blended fabric was repeatedly immersed and dried in the impregnation solution until the mass fraction of phenolic resin and aramid nanofiber-BNNs@Ag hybrid mixture in the obtained composite blended fabric prepreg reached 30%, to obtain a composite blended fabric prepreg.

[0071] The composite blended fabric prepreg was pasted on the surface of 17-4PH metal substrate by phenolic resin, and then heated to 190°C at a heating rate of 5°C / min, and cured at 0.3 MPa for 2 h, to obtain an aramid nanofiber-BNNs@Ag hybrid reinforced self-lubricating fabric pad material.

[0072] Example 4

[0073] 1.5 g of KOH was dissolved in 20 mL of deionized water, and then the above KOH solution was added to 480 mL of DMSO solvent and stirred and dispersed uniformly. 1 g of aramid fiber was dispersed in the above mixed solution, and stirred at 40°C for 4 h. Then the above mixed solution was diluted, filtered, washed and dried to obtain aramid nanofiber.

[0074] 0.8g BNNs (boron nitride nanosheet) was dispersed in 100 mL N,N-dimethylformamide solution, ultrasonic dispersion for 30 min, and the boron nitride nanosheet was further ultrasonic exfoliation; 0.2g polyvinylpyrrolidone was added to the solution, and after stirring and dispersing uniformly; further 0.27g silver nitrate was added to the mixture, and stirred at 60℃ for 2h; finally, the above mixture was washed by centrifugation, freeze-drying to obtain BNNs@Ag hybrid filler.

[0075] 10g phenolic resin glue solution was dispersed in 70mL ethanol-ethyl acetate-acetone mixed solvent, the volume ratio of ethanol, ethyl acetate and acetone was 1:1:1, to obtain a phenolic resin solution; the phenolic resin solution was mixed with 0.05g aramid nanofiber and 0.05g BNNs@Ag hybrid, the mass fraction of aramid nanofiber and BNNs@Ag hybrid in the phenolic resin was 0.5wt% and 0.5wt% respectively, to obtain a resin impregnation solution.

[0076] The meta-aramid fiber-polytetrafluoroethylene fiber blended fabric was obtained by using polytetrafluoroethylene fiber as weft and meta-aramid fiber as warp, with warp density of 400 roots / 10cm and weft density of 350 roots / 10cm, and then air plasma modification treatment was carried out at 100W for 10min; the obtained blended fabric was repeatedly immersed and dried in the impregnation solution until the mass fraction of phenolic resin and aramid nanofiber-BNNs@Ag hybrid mixture in the obtained composite blended fabric prepreg reached 30%, to obtain a composite blended fabric prepreg;

[0077] The composite blended fabric prepreg was pasted on the surface of 17-4PH metal substrate by phenolic resin, and then the temperature was raised to 190℃ at a heating rate of 5℃ / min, and cured at 0.3MPa for 2h, to obtain aramid nanofiber-BNNs@Ag hybrid reinforced self-lubricating fabric gasket material.

[0078] Comparative Example 1

[0079] The difference from Example 1 is only that the preparation process of aramid nanofiber and BNNs@Ag hybrid filler and the mixing process of aramid nanofiber and BNNs@Ag hybrid filler with phenolic resin solution are omitted, to obtain self-lubricating fabric gasket material without loading aramid nanofiber-BNNs@Ag hybrid filler.

[0080] Comparative Example 2

[0081] The difference from Example 1 is only that the preparation process of BNNs@Ag hybrid filler and the mixing process of BNNs@Ag hybrid filler with phenolic resin solution are omitted, to obtain self-lubricating fabric gasket material only loaded with aramid nanofiber filler.

[0082] Performance test

[0083] 1) The friction and wear properties of the aramid nanofiber-BNNs@Ag hybrid reinforced self-lubricating fabric pad materials prepared in Examples 1-4 and the self-lubricating fabric pad materials prepared in Comparative Examples 1-2 were tested. The test conditions were: pressure 102 MPa, sliding friction linear velocity 0.26 m / s, time 120 min, temperature room temperature, and basalt No. 3 friction and wear tester was used with a 2 mm diameter 45 steel as the friction pair. The friction coefficient was automatically output after the data collected by the connected computer was processed. The wear depth of the self-lubricating fabric pad material was measured using a digital height gauge, and the wear volume of the fabric pad was calculated. The specific wear rate of the fabric pad material was calculated using the formula K = ΔV / P·L, and the friction coefficient was automatically exported by the instrument. Wherein, K- specific wear rate; ΔV- wear volume; P- applied load; L- sliding distance. The test results are shown in Table 1.

[0084] Table 1 Friction and wear data of self-lubricating fabric pad materials prepared in Examples 1-4 and Comparative Examples 1-2

[0085]

[0086] As can be seen from Table 1, the wear rate of the aramid nanofiber-BNNs@Ag hybrid reinforced self-lubricating fabric pad material prepared in Example 2 was 0.74 x 10 -14 m 3 (Nm) -1 , and the friction coefficient was 0.059; which was reduced by 56% and 26.3% respectively compared with Comparative Example 1, achieving significant improvement in wear resistance and lubrication performance of the self-lubricating fabric pad. Figure 1 The wear rate and friction coefficient of the self-lubricating fabric pad materials prepared in Comparative Example 1 and Example 2 are shown in the following figure, Figure 1 wherein (a) is the friction coefficient figure, and (b) is the wear rate figure.

[0087] 2) The morphology of the aramid nanofiber and BNNs@Ag hybrid prepared in Example 1 was characterized, and the results are shown in Figure 2 wherein (a) and (c) are scanning and transmission pictures of aramid nanofiber, respectively; (b) and (d) are scanning and transmission pictures of BNNs@Ag hybrid, respectively.

[0088] From the above figures, Figure 2 It can be seen that the aramid nanofiber presents a typical one-dimensional linear structure, and the Ag nanoparticles are uniformly loaded on the surface of the boron nitride nanosheet (from the transmission electron microscope picture, it can be seen that the sheet structure is a two-dimensional boron nitride nanosheet, and the particles loaded on the surface of the sheet structure are zero-dimensional silver nanoparticles).

[0089] The above merely describes the preferred embodiments of the present application, and does not limit the present application in any form. It should be noted that, for those skilled in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as within the protection scope of the present application.

Claims

1. A self-lubricating fabric gasket material characterized by, The self-lubricating fabric liner material comprises a self-lubricating fabric and a phenolic resin composite compound on the self-lubricating fabric; the self-lubricating fabric is a meta-aramid fiber-polytetrafluoroethylene fiber blended fabric; the phenolic resin composite compound comprises phenolic resin and a reinforcing filler dispersed in the phenolic resin, the reinforcing filler is a nano reinforcing filler of different dimensions, and the nano reinforcing filler of different dimensions comprises aramid nanofiber and BNNs@Ag hybrid filler, the BNNs@Ag hybrid filler comprises boron nitride nanosheet and silver nanoparticles in-situ loaded on the surface of the boron nitride nanosheet, and the mass ratio of the aramid nanofiber and the BNNs@Ag hybrid filler is (0.5-2):(0.5-2).

2. The self-lubricating fabric gasket material of claim 1, wherein, The preparation method of the BNNs@Ag hybrid filler comprises the following steps: The boron nitride nanosheet is mixed with an organic solvent for ultrasonic exfoliation, and the obtained dispersion liquid is mixed with polyvinylpyrrolidone and silver nitrate for in-situ reduction to obtain the BNNs@Ag hybrid filler.

3. The self-lubricating fabric gasket material of claim 2, wherein, The organic solvent is N,N-dimethylformamide, and the concentration of the boron nitride nanosheet in the organic solvent is 5-10 mg / mL; the ultrasonic exfoliation time is 10-30 min.

4. The self-lubricating fabric gasket material of claim 2, wherein, The concentration of the polyvinylpyrrolidone in the dispersion liquid is 1-3 mg / mL; the mass ratio of the silver nitrate to the boron nitride nanosheet is 1:2-4; the in-situ reduction temperature is 50-70 °C, and the time is 1.5-2.5 h.

5. The self-lubricating fabric gasket material of claim 1, wherein, The mass fraction of the phenolic resin composite compound in the self-lubricating fabric liner material is 15-40%, and the mass of the aramid nanofiber and the BNNs@Ag hybrid filler in the phenolic resin composite compound is 0.5-2% and 0.5-2% of the mass of the phenolic resin, respectively.

6. The method of making a self-lubricating fabric gasket material according to any one of claims 1 to 5, characterized in that, The preparation method comprises the following steps: The nano reinforcing filler of different dimensions is mixed with a phenolic resin solution to obtain an impregnation liquid; The self-lubricating fabric is impregnated in the impregnation liquid, and the fabric pre-impregnated material is obtained after drying; The fabric pre-impregnated material is cured to obtain the self-lubricating fabric liner material.

7. The self-lubricating fabric liner material of any one of claims 1-5 or the self-lubricating fabric liner material prepared by the preparation method of claim 6 is applied in a self-lubricating plain bearing.

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