Ionic liquid modified LDH / MXene hybrid material, preparation method and application thereof, and BF / PTFE self-lubricating fiber fabric composite material

Abstract

The invention provides an ionic liquid modified LDH / MXene hybrid material, a preparation method and application thereof, and a BF / PTFE self-lubricating fiber fabric composite material, and belongs to the technical field of lubricating additives. The preparation method comprises the following steps: preparing a layered bimetal hydroxide coated MXene hybrid material, which is marked as Ti3C2Tx (at) LDH, through a solvothermal method, and then grafting an ionic liquid on the layered bimetal hydroxide coated MXene hybrid material through a bridging effect of a silane coupling agent to prepare an ionic liquid covalent modified layered bimetal hydroxide / MXene hybrid material, which is marked as IL-Ti3C2Tx (at) LDH. The ionic liquid modified LDH / MXene hybrid material is used as the self-lubricating fabric lubricating additive, so that the self-lubricating fabric lubricating additive has good wear resistance and lubricity, has the effects of strong interface bonding and long-acting lubrication, and can avoid lubrication failure caused by stress concentration.

Description

Technical Field

[0001] This invention relates to the field of lubricant additive technology, specifically to an ionic liquid-modified LDH / MXene hybrid material, its preparation method and application, and a BF / PTFE self-lubricating fiber fabric composite material. Background Technology

[0002] Fabric-reinforced resin-based self-lubricating composites are composite materials composed of high-performance fiber fabrics and resins used to encapsulate the fibers. They offer advantages such as high load-bearing capacity, corrosion resistance, and maintenance-free operation, and are widely used in critical friction components such as aerospace joint bearing liners and high-speed bearing cages. Basalt fiber, as a natural mineral fiber, boasts advantages such as low manufacturing cost, abundant raw material sources, and environmentally friendly production processes. Furthermore, its high-temperature resistance and mechanical properties surpass those of common glass fibers. Polymer-based composites using basalt fiber and polytetrafluoroethylene (PTFE) fiber blends as reinforcing phases can combine the lubricating properties of PTFE fibers with the high load-bearing capacity of basalt fibers, showing promising application prospects in systems requiring harsh operating conditions, such as aerospace landing gear and engine transmission systems.

[0003] Because fabric composites have a two-phase structure of fabric and resin, they share some common problems in engineering applications. Under harsh conditions such as high loads or high speeds, the resin layer encasing the fabric is susceptible to shear forces, leading to resin shedding, fiber pull-out, and ultimately material failure. To address this issue, many nanomaterials have been introduced into composites as lubricating additives. Lubricating additives can react with the friction pair or substrate material to form a lubricating friction film, thereby reducing the coefficient of friction and improving wear resistance. For example, two-dimensional nanomaterials such as graphene and MoS2 reduce the coefficient of friction through interlayer slip; zero-dimensional soft metal particles, such as Ag and Cu, can improve lubrication performance through the "nano-bearing" effect. However, single fillers still have significant limitations. For instance, two-dimensional nanosheets suffer from edge stress concentration due to in-plane anisotropy; zero-dimensional nanoparticles, due to their high surface energy, are prone to agglomeration, causing stress concentration and easily leading to lubrication failure. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide an ionic liquid-modified LDH / MXene hybrid material, its preparation method and application, and a BF / PTFE self-lubricating fiber fabric composite material. The ionic liquid-modified LDH / MXene hybrid material provided by this invention exhibits low friction and stable dispersion at high temperatures. When used as a lubricating additive for self-lubricating fabrics, it demonstrates strong interfacial bonding and long-lasting lubrication, effectively preventing lubrication failure caused by stress concentration.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing an ionic liquid-modified LDH / MXene hybrid material, comprising the following steps: Provide Ti3C2T x Nanosheets, the Ti3C2T x The nanosheets are few-layer and / or monolayer nanosheets; The Ti3C2T x Nanosheets were mixed with an aqueous solution of polyethyleneimine to obtain a PEI-MXene composite material; The PEI-MXene composite material is mixed with a bimetallic hydroxide precursor solution and subjected to a solvothermal reaction to obtain a layered bimetallic hydroxide-coated MXene hybrid material; the bimetallic hydroxide precursor solution comprises nickel salt, aluminum salt, ammonium fluoride, urea and a reducing agent. The MXene hybrid material coated with the layered bimetallic hydroxide, the silane coupling agent, and the organic solvent were mixed and grafted to obtain the silane coupling agent-grafted hybrid material. The hybrid material grafted with the silane coupling agent is mixed with an ionic liquid, a catalyst, and an organic solvent to carry out a coupling reaction, thereby obtaining an ionic liquid-modified LDH / MXene hybrid material.

[0006] Preferably, in the polyethyleneimine aqueous solution, the mass ratio of polyethyleneimine to water is 0.02~0.2g:20~80mL; The Ti3C2T x The mass ratio of nanosheets to polyethyleneimine is 0.1~0.5:0.02~0.2; The mixing temperature is 20~80℃, and the time is 0.5~6h.

[0007] Preferably, in the bimetallic hydroxide precursor solution, the reducing agent includes one or more of sodium citrate, hydrazine hydrate, and ascorbic acid; The mass ratio of the nickel salt, aluminum salt, ammonium fluoride, urea, and reducing agent is (0.5~1):(0.3~0.5):(0.1~0.2):(1~1.5):(0.1~0.3). The solvothermal reaction is carried out at a temperature of 80~160℃ for a duration of 8~24h.

[0008] Preferably, the silane coupling agent includes one or more of KH550, KH560 and KH570; The mass ratio of the layered bimetallic hydroxide-coated MXene hybrid material to the silane coupling agent is (0.2~1):(0.05~0.5). The grafting reaction is preferably carried out at a temperature of 30-80°C for 2-12 hours.

[0009] Preferably, the ionic liquid includes one or more of [BMIM][TOS], [BMIM][PF6], and [BMIM][NTf2]; The catalyst includes EDC; The mass ratio of the hybrid material grafted with the silane coupling agent to the ionic liquid is (0.2~0.8):(0.4~2). The coupling reaction is carried out at a temperature of 40~100℃ for a time of 6~16h.

[0010] The present invention provides an ionic liquid-modified LDH / MXene hybrid material prepared by the above preparation method, comprising an MXene hybrid material coated with a double layer of metal hydroxide, and an ionic liquid grafted onto the surface of the MXene hybrid material coated with the double layer of metal hydroxide by a silane coupling agent.

[0011] This invention provides the application of the above-mentioned ionic liquid-modified LDH / MXene hybrid material as a self-lubricating fabric lubricant additive.

[0012] This invention provides a BF / PTFE self-lubricating fiber fabric composite material, comprising a BF / PTFE fiber fabric and a functional resin impregnated on the surface and interfiber spaces of the BF / PTFE fiber fabric; the functional resin comprises a resin matrix and the aforementioned ionic liquid-modified LDH / MXene hybrid material dispersed in the resin matrix; The weft yarns of the BF / PTFE fiber fabric include basalt fibers, and the warp yarns include polytetrafluoroethylene fibers.

[0013] Preferably, the mass of the ionic liquid-modified LDH / MXene hybrid material is 0.2-8% of the mass of the resin matrix; The mass of the BF / PTFE fiber fabric is 50-80% of the mass of the BF / PTFE self-lubricating fiber fabric composite material.

[0014] This invention provides a method for preparing the above-mentioned BF / PTFE self-lubricating fiber fabric composite material, comprising the following steps: The ionic liquid-modified LDH / MXene hybrid material was mixed with a dilute resin solution to obtain an impregnation solution; The BF / PTFE fiber fabric is mixed with the impregnation liquid, and then impregnated, dried and heat-cured in sequence to obtain the BF / PTFE self-lubricating fiber fabric composite material.

[0015] This invention provides a method for preparing an ionic liquid-modified LDH / MXene hybrid material. The invention utilizes a solvothermal method to prepare a layered bimetallic hydroxide-coated MXene hybrid material, denoted as Ti3C2T.x @LDH, and then through the bridging effect of silane coupling agent, ionic liquids are grafted onto the layered bimetallic hydroxide-coated MXene hybrid material to prepare an ionic liquid covalently modified layered bimetallic hydroxide / MXene hybrid material, denoted as IL-Ti3C2T. x @LDH. In this invention, MXene serves as the core, providing mechanical support and conductivity. The LDH shell enhances interfacial stability through intercalation with anions, and the ionic liquid acts as the outermost lubricating layer, achieving long-term lubrication. During friction, cations (such as imidazole cations) and anions (such as sulfonate anions) in the ionic liquid form a dynamic ionic liquid film with low shear strength at the friction interface, significantly reducing the stick-slip effect. The long alkyl chains of the ionic liquid (IL) preferentially decompose at instantaneous high temperatures, generating a tribochemical reaction film containing phosphorus and sulfur, improving load-bearing and anti-adhesion capabilities. Covalent grafting enhances the interfacial compatibility between LDH / MXene and the resin matrix, preventing the aggregation of nanofillers and ensuring that the lubricating components participate uniformly and continuously in the interfacial interaction. The ionic liquid-modified LDH / MXene hybrid material provided by this invention successfully improves the problems of poor compatibility and easy aggregation and detachment of traditional fillers and resins, significantly enhancing the wear resistance of the gasket material.

[0016] This invention provides a BF / PTFE self-lubricating fiber fabric composite material, comprising a BF / PTFE fiber fabric and a functional resin impregnated on the surface and interfiber spaces of the BF / PTFE fiber fabric; the functional resin comprises a resin matrix and the aforementioned ionic liquid-modified LDH / MXene hybrid material dispersed in the resin matrix; the weft yarn of the BF / PTFE fiber fabric comprises basalt fiber, and the warp yarn comprises polytetrafluoroethylene fiber. This invention uses the ionic liquid-modified LDH / MXene hybrid material as a lubricating additive, exhibiting both good anti-wear properties and lubricity, strong interfacial bonding, and long-lasting lubrication, thus preventing lubrication failure caused by stress concentration. Attached Figure Description

[0017] Figure 1 LDH / MXene hybrid material modified with ionic liquid (IL-Ti3C2T) x A schematic diagram of the synthesis of @LDH); Figure 2 The IL-Ti3C2T obtained in Example 1 x @LDH's SEM photos; Figure 3 The IL-Ti3C2T obtained in Example 1 x @LDH's TEM photo; Figure 4 The average friction coefficient and wear rate of different test pieces; Figure 5 The images show the surface morphology of FC-5 and FC-0 after wear. Detailed Implementation

[0018] This invention provides a method for preparing an ionic liquid-modified LDH / MXene hybrid material, comprising the following steps: Provide Ti3C2T x Nanosheets, the Ti3C2T x The nanosheets are few-layer and / or monolayer nanosheets; The Ti3C2T x Nanosheets were mixed with an aqueous solution of polyethyleneimine to obtain a PEI-MXene composite material; The PEI-MXene composite material is mixed with a bimetallic hydroxide precursor solution and subjected to a solvothermal reaction to obtain a layered bimetallic hydroxide-coated MXene hybrid material; the bimetallic hydroxide precursor solution comprises nickel salt, aluminum salt, ammonium fluoride, urea and a reducing agent. The MXene hybrid material coated with the layered bimetallic hydroxide, the silane coupling agent, and the organic solvent were mixed and grafted to obtain the silane coupling agent-grafted hybrid material. The hybrid material grafted with the silane coupling agent is mixed with an ionic liquid, a catalyst, and an organic solvent to carry out a coupling reaction, thereby obtaining an ionic liquid-modified LDH / MXene hybrid material.

[0019] Unless otherwise specified, all raw materials used in this invention are commercially available.

[0020] This invention provides Ti3C2T x Nanosheets, the Ti3C2T x The nanosheets are few-layer and / or monolayer nanosheets. In this invention, the Ti3C2T x MXene nanosheets have a few-layer or single-layer structure, with a thickness preferably of 100-500 nm, more preferably 200-400 nm, and a sheet diameter preferably of 1-3 μm. In this invention, the Ti3C2T... x The nanosheets are preferably prepared by acid etching and ultrasonic exfoliation. In this invention, the Ti3C2T x The preferred method for preparing nanosheets includes the following steps: Ti3AlC2 was mixed with an acid etching solution and acid etched to obtain a crude product; The crude product is mixed with water and centrifuged multiple times until the pH of the supernatant is 6-8, and the lower precipitate is collected. The lower precipitate was mixed with water and subjected to ultrasonic exfoliation to obtain Ti3C2T. x Nanosheets.

[0021] In this invention, the acid etching solution is a mixture of LiF and HCl, preferably with a HCl concentration of 9 M and a LiF concentration of 0.033 g / mL. The mass ratio of Ti3AlC2 to the volume ratio of the acid etching solution is preferably 0.5-2 g:30 mL, more preferably 1 g:30 mL. The etching temperature is preferably 30-60°C, more preferably 40-50°C, and the etching time is preferably 24-48 h, more preferably 30-40 h.

[0022] In this invention, the multiple centrifugations are performed until the pH value of the supernatant is 6-8, more preferably 7.

[0023] In this invention, the ultrasonic ablation is preferably performed under a nitrogen atmosphere, the ultrasonic ablation power is preferably 100~300Hz, more preferably 200Hz, and the time is preferably 1~2h, more preferably 1.5h.

[0024] The present invention uses the Ti3C2T x Nanosheets are stirred and mixed with an aqueous solution of polyethyleneimine (PEI) to obtain a PEI-MXene composite material. In this invention, the mass ratio of polyethyleneimine to water in the aqueous solution is 0.02~0.2g:20~80mL, preferably 0.05~0.15g:40~60mL. In this invention, the Ti3C2T... x The mass ratio of nanosheets to polyethyleneimine is preferably 0.1~0.5:0.02~0.2, more preferably 0.2~0.4:0.05~0.15.

[0025] In this invention, the mixing temperature is preferably 20~80℃, more preferably 40~60℃; the mixing time is preferably 0.5~6h, more preferably 1~5h, and even more preferably 2~4h. After mixing, the resulting mixture is preferably centrifuged to remove free PFI.

[0026] In this invention, in the PEI-MXene composite material, PEI can achieve amino functionalization of MXene in various ways. The amino group (-NH2) of PEI can bind to LDH in the following ways: ① Electrostatic attraction: with positively charged metal ions (such as Ni) on the LDH layer. 2+ Al 3+ The interaction mechanisms include: ① binding; ② coordination: amino groups act as electron donors, forming coordination bonds with the metal sites of LDH; ③ hydrogen bonding: forming a hydrogen bond network with hydroxyl groups (-OH) on the LDH surface or with interlayer water molecules. Through these three interaction mechanisms, PEI acts as a "molecular bridge" to stabilize the interface between LDH and MXene, thereby improving the mechanical strength and stability of the composite material.

[0027] After obtaining the PEI-MXene composite material, the present invention mixes the PEI-MXene composite material with a bimetallic hydroxide precursor solution and performs a solvothermal reaction to obtain a layered bimetallic hydroxide-coated MXene hybrid material. In the present invention, the bimetallic hydroxide precursor solution comprises a nickel salt, an aluminum salt, ammonium fluoride, urea, and a reducing agent. In the present invention, the nickel salt is preferably Ni(NO3)2·6H2O, and the aluminum salt is preferably Al(NO3)3·9H2O; the reducing agent preferably includes one or more of sodium citrate, hydrazine hydrate, and ascorbic acid, more preferably sodium citrate. In this invention, the preferred mass ratio of the nickel salt, aluminum salt, ammonium fluoride, urea, and reducing agent is (0.5~1):(0.3~0.5):(0.1~0.2):(1~1.5):(0.1~0.3), more preferably (0.6~0.8):0.4:(0.1~0.2):(1.2~1.4):0.2. In this invention, the solvent for the bimetallic hydroxide precursor solution is preferably a mixed solvent of water and ethylene glycol, and the preferred volume ratio of water to ethylene glycol is 10~60:5~15, more preferably 10:20~50. In this invention, the preferred mass ratio of the nickel salt to the volume ratio of the mixed solvent is 0.5~1.0g:15~75mL.

[0028] In this invention, the mass ratio of the PEI-MXene composite material to the nickel salt is preferably 0.2~0.6:0.5~1, more preferably 0.3~0.5:0.6~0.8. In this invention, the temperature of the solvothermal reaction is preferably 80~160℃, more preferably 100~140℃, and the time is preferably 8~24h, more preferably 12~18h. After the solvothermal reaction, the resulting solvothermal reaction solution is preferably centrifuged, washed, and dried.

[0029] After obtaining the layered bimetallic hydroxide-coated MXene hybrid material, the present invention mixes the layered bimetallic hydroxide-coated MXene hybrid material, a silane coupling agent, and an organic solvent to perform a grafting reaction, thereby obtaining a silane coupling agent-grafted hybrid material. In the present invention, the silane coupling agent preferably includes one or more of KH550, KH560, or KH570, more preferably KH550; the organic solvent is preferably one or more of toluene, ethanol, isopropanol, and xylene, more preferably toluene. In the present invention, the mass ratio of the layered bimetallic hydroxide-coated MXene hybrid material to the silane coupling agent is preferably 0.2~1:0.05~0.5, more preferably 0.3~0.8:0.1~0.3. In the present invention, the mass ratio of the silane coupling agent to the volume ratio of the organic solvent is preferably 0.05~0.5g:10~50mL.

[0030] In this invention, the grafting reaction is preferably carried out under stirring conditions, the temperature of the grafting reaction is preferably 30~80℃, more preferably 40~60℃, and the time is preferably 2~12h, more preferably 4~8h. After the grafting reaction, the obtained grafting reaction product is preferably washed, the washing reagent is preferably ethanol, and the washing method is preferably centrifugal washing.

[0031] After obtaining the silane coupling agent-grafted hybrid material, the present invention mixes the silane coupling agent-grafted hybrid material with an ionic liquid, a catalyst, and an organic solvent to carry out a coupling reaction, thereby obtaining an ionic liquid-modified LDH / MXene hybrid material. In the present invention, the ionic liquid preferably includes one or more of [BMIM][TOS], [BMIM][PF6], and [BMIM][NTf2], more preferably [BMIM][TOS]; the catalyst preferably includes EDC (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide); and the organic solvent preferably includes one or more of N,N-dimethylformamide (DMF), dichloromethane, acetonitrile, and tetrahydrofuran.

[0032] In this invention, the ionic liquid [BMIM][TOS] is stably immobilized on silanized Ti3C2T via covalent grafting. x @LDH surface. Among them, the p-toluenesulfonic acid anion ([TOS]) in the ionic liquid... - The sulfonic acid group (-SO3H) of the sulfonic acid reacts with the amino group (-NH2) introduced by the silane coupling agent KH550 to form a stable sulfonamide bond (-SO2-NH-). This process is completed under the action of the catalyst EDC (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide): EDC first activates the sulfonic acid group to generate a highly reactive O-acyl isourea intermediate, which then undergoes a nucleophilic substitution reaction with the primary amine, ultimately forming a covalently bonded "core-shell-lubricating layer" structure. In this invention, the catalytic effect of EDC significantly improves the reaction efficiency and selectivity between sulfonic acid and amine. Its byproduct is a water-soluble urea derivative, which can be completely removed by washing and does not affect the final performance of the hybrid material.

[0033] In this invention, the mass ratio of the silane coupling agent-grafted hybrid material to the ionic liquid is preferably 0.2~0.8:0.4~2, more preferably 0.4~0.6:1~1.5; the mass ratio of the silane coupling agent-grafted hybrid material to the catalyst is preferably 0.2~0.8:0.05~0.2, more preferably 0.4~0.6:0.1~0.15. In this invention, the mass ratio of the silane coupling agent-grafted hybrid material to the volume ratio of the organic solvent is preferably 0.2~0.8 g:10~60 mL.

[0034] In this invention, the coupling reaction is preferably carried out under stirring conditions, the temperature of the coupling reaction is preferably 40-100°C, more preferably 60-80°C, and the time is preferably 6-16 h, more preferably 8-14 h. After the coupling reaction, the resulting coupling product is preferably washed and dried. In this invention, the washing reagent is preferably DMF and ethanol, and the washing method is preferably centrifugal washing. This invention removes free ionic liquids through washing. In this invention, the drying is preferably vacuum drying, the drying temperature is preferably 40-80°C, more preferably 60°C, and the drying time is preferably 6-18 h, more preferably 12-15 h.

[0035] In this invention, the ionic liquid-modified LDH / MXene hybrid material (IL-Ti3C2T) x A schematic diagram of the synthesis of @LDH is shown below. Figure 1 As shown.

[0036] This invention provides an ionic liquid-modified LDH / MXene hybrid material prepared by the above-described method, comprising an MXene hybrid material coated with a bilayer metal hydroxide, and an ionic liquid grafted onto the surface of the MXene hybrid material coated with the bilayer metal hydroxide via a silane coupling agent. In this invention, the bilayer metal hydroxide is nickel-aluminum hydrotalcite; the MXene is Ti3C2T. x Nanosheets, the Ti3C2T x The nanosheets are few-layer and / or single-layer nanosheets; the ionic liquid is preferably [BMIM][TOS].

[0037] In this invention, the mass percentage of the ionic liquid in the ionic liquid-modified LDH / MXene hybrid material is preferably 20-40%, more preferably 30%; the mass percentage of the bilayer metal oxide is preferably 20-40%, more preferably 30%; and the particle size of the ionic liquid-modified LDH / MXene hybrid material is preferably 100 nm to 1 μm, more preferably 200-800 nm, and even more preferably 300-500 nm.

[0038] This invention provides the application of the above-mentioned ionic liquid-modified LDH / MXene hybrid material as a lubricating additive for self-lubricating fabrics. In this invention, the self-lubricating fabric is preferably a fabric-reinforced resin-based self-lubricating composite material.

[0039] This invention provides a BF / PTFE self-lubricating fiber fabric composite material, comprising a BF / PTFE fiber fabric and a functional resin impregnated on the surface and interfiber spaces of the BF / PTFE fiber fabric; the functional resin comprises a resin matrix and an ionic liquid-modified LDH / MXene hybrid material dispersed in the resin matrix; the weft yarn of the BF / PTFE fiber fabric comprises basalt fiber (BF), and the warp yarn comprises polytetrafluoroethylene fiber (PTFE).

[0040] In this invention, the diameter of the BF fiber is preferably 5-20 μm, more preferably 10-15 μm; the diameter of the PTFE fiber is preferably 10-30 μm, more preferably 15-20 μm. In this invention, the weave structure of the BF / PTFE fiber fabric is one or more of broken twill, 3 / 1 twill, and 2 / 2 twill. In this invention, the mass ratio of PTFE fiber to basalt fiber in the BF / PTFE fiber fabric is 1-2:1, more preferably 1.5:1, and the volume ratio is preferably 1.5-3:1, more preferably 2-2.5:1. In this invention, the warp density of the BF / PTFE fiber fabric is preferably 300-350 threads / 10cm, and the weft density is preferably 250-350 threads / 10cm.

[0041] In this invention, the resin is preferably one or more selected from phenolic resin, polyimide resin, epoxy resin, and polyamide-imide resin. In this invention, the mass of the ionic liquid-modified LDH / MXene hybrid material is preferably 0.2-8% of the resin matrix mass, more preferably 1-5%, specifically 0.2%, 0.5%, 1%, 3%, 5%, or 8%. In this invention, the mass of the BF / PTFE fiber fabric is preferably 50-80% of the BF / PTFE self-lubricating fiber fabric composite material mass, more preferably 60-70%.

[0042] This invention provides a method for preparing the above-mentioned BF / PTFE self-lubricating fiber fabric composite material, comprising the following steps: The ionic liquid-modified LDH / MXene hybrid material was mixed with a dilute resin solution to obtain an impregnation solution; The BF / PTFE fiber fabric is mixed with the impregnation liquid, and then impregnated, dried and heat-cured in sequence to obtain the BF / PTFE self-lubricating fiber fabric composite material.

[0043] This invention involves mixing an ionic liquid-modified LDH / MXene hybrid material with a dilute resin solution to obtain an impregnation solution. In this invention, the resin content in the dilute resin solution is preferably 10-20% by mass, more preferably 15%. The diluent for the dilute resin solution is preferably a mixed solvent of anhydrous ethanol, acetone, and ethyl acetate, with a preferred volume ratio of 1:1:1. In this invention, the mixing method is preferably ultrasonic mixing.

[0044] In this invention, the impregnation time is preferably 10-20 seconds, and the drying temperature is preferably 30-60°C. Preferably, the impregnation-drying process is repeated multiple times until the mass of the BF / PTFE fiber fabric is 50-80% of the mass of the BF / PTFE self-lubricating fiber fabric composite material.

[0045] In this invention, the thermosetting temperature is preferably 80~300℃, more preferably 100~250℃, and even more preferably 150~200℃; the thermosetting time is preferably 100~300min, more preferably 150~250min, and even more preferably 200min. In this invention, the thermosetting pressure is preferably 0.1~1MPa, more preferably 0.5MPa; the heating rate of the thermosetting temperature is preferably 2~18℃ / min, more preferably 5~10℃ / min.

[0046] In actual testing or use, the present invention preferably involves bonding a BF / PTFE fiber fabric impregnated with an impregnation solution to the surface of a metal substrate, followed by heat curing. In the present invention, the adhesive used for bonding is preferably a phenolic resin adhesive.

[0047] The following detailed descriptions, in conjunction with embodiments, illustrate an ionic liquid-modified LDH / MXene hybrid material, its preparation method, and its application, as well as a BF / PTFE self-lubricating fiber fabric composite material provided by the present invention. However, these descriptions should not be construed as limiting the scope of protection of the present invention.

[0048] Example 1 Ionic liquid-modified LDH / MXene hybrid material (IL-Ti3C2T) x The preparation of @LDH) is carried out using the following steps: 1 g LiF was dissolved in 30 mL of 9 M HCl and stirred for 10 min. 1 g Ti3AlC2 was slowly added, and the mixture was stirred at 40 °C for 48 h. The solution was centrifuged multiple times at 3500 rpm for 5 min until neutral. After ultrasonic exfoliation, the solution was freeze-dried to obtain few-layer and monolayer Ti3C2T. x Nanosheets. 0.2g of Ti3C2T... xPEI-MXene was obtained by dispersing PEI in 40 mL of an aqueous solution containing 0.05 g of PEI and stirring at 60 °C for 2 h, followed by centrifugation. 0.58 g of Ni(NO3)2·6H2O, 0.375 g of Al(NO3)3·9H2O, 1.2 g of urea, 0.15 g of NH4F, and 0.2 g of sodium citrate were dissolved in 30 mL of water and mixed with 0.2 g of PEI-MXene. 10 mL of ethylene glycol was added, and the mixture was sonicated for 30 min to form a homogeneous precursor solution. The solution was then subjected to hydrothermal reaction at 120 °C for 12 h to obtain a layered bimetallic hydroxide-coated MXene hybrid material, denoted as Ti3C2T. x @LDH; 1g Ti3C2T x @LDH was dispersed in 50 mL of toluene, 0.5 g of KH550 was added, and the mixture was refluxed at 80 °C for 6 h. After centrifugation and washing, it was dispersed in 30 mL of DMF, 1.5 g of [BMIM][TOS] and 0.2 g of EDC were added, and the mixture was reacted at 60 °C for 12 h. After centrifugation and washing, the mixture was vacuum dried at 60 °C to obtain a layered bimetallic hydroxide / MXene hybrid material covalently grafted with ionic liquid, denoted as IL-Ti3C2T. x @LDH.

[0049] The obtained IL-Ti3C2T x @LDH's SEM and TEM photos, as shown Figure 2 , Figure 3 As shown. By Figure 2 , Figure 3 It can be seen that IL-Ti3C2T x @LDH exhibits clusters formed by nano-sized spheres.

[0050] Example 2 The preparation method of BF / PTFE self-lubricating fiber fabric composite material adopts the following steps: (1) A blended woven fabric made of BF fiber and PTFE fiber (the structure is a broken twill weave, the warp density is 326 threads / cm, and the weft density is 290 threads / cm) is washed with alkali (the reagent is a sodium hydroxide solution with a pH of 10, the alkali washing temperature is 95℃, and the time is 20min), washed with deionized water until neutral, and dried to obtain a pretreated BF / PTFE fiber fabric.

[0051] (2) The pretreated BF / PTFE fiber fabric is repeatedly impregnated in an impregnation solution containing IL-Ti3C2T. x @LDH phenolic resin solution (phenolic resin mass fraction 15%, diluent is a mixed solvent of anhydrous ethanol, acetone and ethyl acetate in a volume ratio of 1:1:1, IL-Ti3C2T) x@LDH mass accounts for 1wt% of phenolic resin mass, until the fabric mass fraction reaches 70±5wt%, to obtain uncured BF / PTFE self-lubricating fiber fabric composite material.

[0052] (3) Phenolic resin adhesive was used to bond it to the surface of Q235 steel substrate and cured at 184℃ for 2h to obtain a domestically produced self-lubricating fiber fabric composite material test piece, named FC-5.

[0053] Comparative Example 1 The difference from Example 2 is that the impregnation solution in step (2) does not contain IL-Ti3C2T. x @LDH is a simple phenolic resin solution (phenolic resin mass fraction is 15%, and the diluent is a mixture of anhydrous ethanol, acetone and ethyl acetate in a volume ratio of 1:1:1). The resulting domestically produced self-lubricating fiber fabric composite test specimen is named FC-0.

[0054] Comparative Example 2 Compared with Example 2, the difference is that the impregnation solution in step (2) is a phenolic resin solution containing nickel-aluminum hydrotalcite (the mass of nickel-aluminum hydrotalcite is 1 wt% of the phenolic resin, the mass fraction of the phenolic resin is 15%, and the diluent is a mixed solvent of anhydrous ethanol, acetone and ethyl acetate in a volume ratio of 1:1:1). The resulting domestically produced self-lubricating fiber fabric composite material test piece is named FC-1.

[0055] The preparation method of nickel-aluminum hydrotalcite includes the following steps: 0.58g Ni(NO3)2·6H2O, 0.375g Al(NO3)3·9H2O, 1.2g urea, 0.15g NH4F, and 0.2g sodium citrate were dissolved in 30mL of water, and 10mL of ethylene glycol was added. The mixture was sonicated for 30min to form a homogeneous precursor solution. The solution was then subjected to hydrothermal reaction at 120℃ for 12h to obtain nickel-aluminum hydrotalcite.

[0056] Comparative Example 3 Compared with Example 2, the difference is that the impregnation solution in step (2) contains Ti3C2T. x Phenolic resin solution of nanosheets (Ti3C2T) x The nanosheets were 1 wt% of the phenolic resin, which had a mass fraction of 15%. The diluent was a mixture of anhydrous ethanol, acetone, and ethyl acetate in a volume ratio of 1:1:1. The resulting domestically produced self-lubricating fiber fabric composite test specimen was named FC-2.

[0057] Among them, Ti3C2T x The preparation method of the nanosheets is as described in Example 1.

[0058] Comparative Example 4 Compared with Example 2, the difference is that the impregnation solution in step (2) is a phenolic resin solution containing [BMIM][TOS] ionic liquid (the mass of [BMIM][TOS] ionic liquid is 1 wt% of phenolic resin, the mass fraction of phenolic resin is 15%, and the diluent is a mixed solvent of anhydrous ethanol, acetone and ethyl acetate in a volume ratio of 1:1:1). The resulting domestically produced self-lubricating fiber fabric composite test piece is named FC-3.

[0059] Comparative Example 5 Compared with Example 2, the difference is that the impregnation solution in step (2) is a layered bimetallic hydroxide-coated MXene hybrid material (Ti3C2T). x Phenolic resin solution (Ti3C2T) of @LDH x The mass of @LDH was 1 wt% of phenolic resin, the mass fraction of phenolic resin was 15%, and the diluent was a mixture of anhydrous ethanol, acetone, and ethyl acetate in a volume ratio of 1:1:1. The resulting domestically produced self-lubricating fiber fabric composite test specimen was named FC-4.

[0060] Performance testing (1) The friction and wear performance of the test pieces obtained in Example 2 and Comparative Examples 1-5 were evaluated using the Xuanwu No. 3 bolt-disc friction and wear testing machine. The test conditions were room temperature, load of 70 MPa, speed of 0.262 m / s, and test time of 120 min. The results are shown in Table 1. The average friction coefficient and wear rate of different test pieces are as follows: Figure 4 As shown, Figure 4 In the figure, (a) represents the wear rate and (b) represents the coefficient of friction.

[0061] Table 1. Test results of average friction coefficient and wear rate of the test specimens obtained in Example 2 and Comparative Examples 1-5.

[0062] It can be seen that the wear rate of pure BF / PTFE self-lubricating fiber fabric composite material is relatively high. After adding different lubricating fillers, the wear rate of BF / PTFE self-lubricating material is significantly reduced; the addition of IL-Ti3C2T... x @LDH's FC-5 exhibits the lowest average wear rate.

[0063] (2) Surface morphology diagrams of FC-5 and FC-0 after wear are shown below. Figure 5 As shown, Figure 5 In the image, (a) shows the surface morphology of FC-0 after wear, and (b) shows the surface morphology of FC-5 after wear. Figure 5It can be clearly seen that the pure BF / PTFE self-lubricating fiber fabric composite exhibits the most severe wear, with obvious resin peeling marks and a series of parallel furrows. For the addition of IL-Ti3C2T... x @LDH's FC-5 exhibits a smooth wear surface with only some plastic deformation of the resin, indicating slight fatigue wear, consistent with its minimal wear rate. This is attributed to the good compatibility between the hybrid particles and the polymer matrix.

[0064] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an ionic liquid-modified LDH / MXene hybrid material, characterized in that, Includes the following steps: Provide Ti3C2T x Nanosheets, the Ti3C2T x The nanosheets are few-layer and / or monolayer nanosheets; The Ti3C2T x Nanosheets were stirred and mixed with an aqueous solution of polyethyleneimine to obtain a PEI-MXene composite material; The PEI-MXene composite material is mixed with a bimetallic hydroxide precursor solution and subjected to a solvothermal reaction to obtain a layered bimetallic hydroxide-coated MXene hybrid material; the bimetallic hydroxide precursor solution comprises nickel salt, aluminum salt, ammonium fluoride, urea and a reducing agent. The MXene hybrid material coated with the layered bimetallic hydroxide, the silane coupling agent, and the organic solvent were mixed and grafted to obtain the silane coupling agent-grafted hybrid material. The hybrid material grafted with the silane coupling agent is mixed with an ionic liquid, a catalyst, and an organic solvent to carry out a coupling reaction, thereby obtaining an ionic liquid-modified LDH / MXene hybrid material.

2. The preparation method according to claim 1, characterized in that, In the aqueous solution of polyethyleneimine, the mass ratio of polyethyleneimine to water is 0.02~0.2g:20~80mL; The Ti3C2T x The mass ratio of nanosheets to polyethyleneimine is 0.1~0.5:0.02~0.2; The mixing temperature is 20~80℃, and the time is 0.5~6h.

3. The preparation method according to claim 1, characterized in that, In the bimetallic hydroxide precursor solution, the reducing agent includes one or more of sodium citrate, hydrazine hydrate, and ascorbic acid; The mass ratio of the nickel salt, aluminum salt, ammonium fluoride, urea, and reducing agent is (0.5~1):(0.3~0.5):(0.1~0.2):(1~1.5):(0.1~0.3). The solvothermal reaction is carried out at a temperature of 80~160℃ for a duration of 8~24h.

4. The preparation method according to claim 1, characterized in that, The silane coupling agent includes one or more of KH550, KH560 and KH570; The mass ratio of the layered bimetallic hydroxide-coated MXene hybrid material to the silane coupling agent is (0.2~1):(0.05~0.5). The grafting reaction is preferably carried out at a temperature of 30-80°C for 2-12 hours.

5. The preparation method according to claim 1, characterized in that, The ionic liquid includes one or more of [BMIM][TOS], [BMIM][PF6], and [BMIM][NTf2]; The catalyst includes EDC; The mass ratio of the hybrid material grafted with the silane coupling agent to the ionic liquid is (0.2~0.8):(0.4~2). The coupling reaction is carried out at a temperature of 40~100℃ for a time of 6~16h.

6. The ionic liquid-modified LDH / MXene hybrid material prepared by the preparation method according to any one of claims 1 to 5, characterized in that, It includes an MXene hybrid material encapsulated in a double layer of metal hydroxide, and an ionic liquid grafted onto the surface of the MXene hybrid material encapsulated in the double layer of metal hydroxide by a silane coupling agent.

7. The application of the ionic liquid-modified LDH / MXene hybrid material of claim 6 as a self-lubricating fabric lubricant additive.

8. A BF / PTFE self-lubricating fiber fabric composite material, characterized in that, The invention comprises a BF / PTFE fiber fabric, and a functional resin impregnated on the surface and interfiber spaces of the BF / PTFE fiber fabric; the functional resin comprises a resin matrix and an ionic liquid-modified LDH / MXene hybrid material as described in claim 6 dispersed in the resin matrix. The weft yarns of the BF / PTFE fiber fabric include basalt fibers, and the warp yarns include polytetrafluoroethylene fibers.

9. The BF / PTFE self-lubricating fiber fabric composite material according to claim 8, characterized in that, The mass of the ionic liquid-modified LDH / MXene hybrid material is 0.2-8% of the mass of the resin matrix; The mass of the BF / PTFE fiber fabric is 50-80% of the mass of the BF / PTFE self-lubricating fiber fabric composite material.

10. The method for preparing the BF / PTFE self-lubricating fiber fabric composite material according to claim 8 or 9, characterized in that, Includes the following steps: The ionic liquid-modified LDH / MXene hybrid material was mixed with a dilute resin solution to obtain an impregnation solution; The BF / PTFE fiber fabric is mixed with the impregnation liquid, and then impregnated, dried and heat-cured in sequence to obtain the BF / PTFE self-lubricating fiber fabric composite material.

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