Cu@Co MOF nanofluids and nanofluid-reinforced blended fabric composites, their preparation and applications

Abstract

This invention provides a Cu@CoMOF nanofluid and a nanofluid-reinforced blended fabric composite material, as well as their preparation and application, relating to the field of solid lubricant materials technology. First, Co-MOF materials are grown in situ on the surface of a Cu-BTC metal-organic framework compound to construct a Cu@CoMOF hybrid, serving as the core of the nanofluid. Then, an inner crown of DC-5700 and an outer crown of PEGs are grafted onto the outside of the core to prepare the Cu@CoMOF nanofluid. The Cu@CoMOF nanofluid prepared by this invention exhibits good compatibility with the resin matrix of the blended fabric composite material, fully leveraging the synergistic reinforcing effect of Cu-BTC and Co-MOF. The Cu@CoMOF nanofluid, introduced as a nano-reinforcing agent into the blended fabric composite material, can significantly improve the tribological properties of the composite material.

Description

Technical Field

[0001] This invention relates to the field of solid lubricant materials technology, and more particularly to Cu@Co MOF nanofluids and nanofluid-reinforced blended fabric composites, their preparation and application. Background Technology

[0002] As a core component of self-lubricating spherical plain bearings, the tribological properties of self-lubricating fabric liner materials directly determine the performance and service life of the bearings. Self-lubricating fabric liner materials are mainly composed of a blended fabric woven from PTFE fibers and high-performance reinforcing fibers (such as PI fibers) and a resin matrix. The PTFE fibers and high-performance reinforcing fibers provide lubrication and load-bearing functions, respectively. However, under extreme and harsh environments, such as heavy-load and high-speed conditions, the transfer film on the mating surfaces of the fabric liner material cannot withstand high shear stress, leading to rapid detachment and severe wear.

[0003] The common approach to solving the above problems is to introduce nanofiller reinforcing agents into the fabric composite material to effectively control the structure of the liner transfer film and improve the tribological properties of the liner. However, the dispersion of nanofillers has always been a key issue affecting the reinforcing effect of fillers. Solvent-free nanofluids combine the small size of monodisperse particles, surface and interface effects, and the physicochemical properties of shell ionic flexible long-chain molecules, exhibiting stable monodispersity and being an essentially single homogeneous system, fundamentally preventing the aggregation of nanoparticles. However, the influence of nanofluids on the tribological properties of fabric composite materials is closely related to their structure, and developing nanofluids that can significantly improve the tribological properties of fabric composite materials has been a problem that researchers have been working to solve. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a Cu@Co MOF nanofluid and a nanofluid-reinforced blended fabric composite material, as well as its preparation and application. The Cu@Co MOF nanofluid prepared by this invention can significantly improve the tribological properties of the blended fabric composite material.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for preparing Cu@Co MOF nanofluids, comprising the following steps:

[0007] (1) A Cu@Co MOF hybrid was obtained by mixing Cu-BTC metal-organic framework compound, alcohol solvent, cobalt nitrate and 2-methylimidazole and carrying out a self-assembly reaction.

[0008] (2) The Cu@Co MOF hybrid, alcohol-water solvent and dimethyloctadecyl[3-trimethoxysilylpropyl]ammonium chloride were mixed and subjected to dehydration condensation reaction to obtain Cu@Co MOF-DC5700 precipitate;

[0009] (3) The Cu@Co MOF-DC5700 precipitate, alcohol solvent and polyethylene glycol 4-nonylphenyl 3-sulfopropyl ether potassium salt were mixed and subjected to electrostatic assembly reaction to obtain Cu@Co MOF nanofluid.

[0010] Preferably, in step (1), the mass ratio of Cu-BTC metal-organic framework compound, cobalt nitrate and 2-methylimidazole is 1:1.5:(4-6); the self-assembly reaction is carried out at room temperature for 4-8 hours.

[0011] Preferably, in step (2), the ratio of Cu@Co MOF hybrid to dimethyloctadecyl[3-trimethoxysilylpropyl]ammonium chloride is 1 g:(2-3) mL; the dehydration condensation reaction is carried out at room temperature for 20-30 h.

[0012] Preferably, in step (3), the mass ratio of Cu@Co MOF-DC5700 precipitate to polyethylene glycol 4-nonylphenyl 3-sulfopropyl ether potassium salt is 1:10-15; the electrostatic assembly reaction is carried out at a temperature of 60-80°C for 20-30 hours.

[0013] This invention provides Cu@Co MOF nanofluids prepared by the above-described technical solution. The Cu@Co MOF nanofluids include a Cu@Co MOF hybrid core and an inner crown and an outer crown grafted sequentially from the inside to the outside onto the surface of the Cu@Co MOF hybrid core. The Cu@Co MOF hybrid core has a core-shell structure, including a Cu-BTC metal-organic framework compound and a Co-MOF material grown in situ on the surface of the Cu-BTC metal-organic framework compound. The inner crown is dimethyloctadecyl[3-trimethoxysilylpropyl]ammonium chloride, and the outer crown is polyethylene glycol 4-nonylphenyl 3-sulfopropyl ether potassium salt.

[0014] This invention provides the application of the Cu@Co MOF nanofluid described in the above technical solution as a nano-reinforcing agent for blended fabric composites.

[0015] This invention provides a nanofluid-reinforced blended fabric composite material, comprising a PI / PTFE blended fabric and a phenolic resin material attached to the surface and interior of the PI / PTFE blended fabric; the phenolic resin material comprises a phenolic resin matrix and a nanofluid, wherein the nanofluid is the Cu@Co MOF nanofluid described in the above technical solution; the mass content of the phenolic resin matrix in the nanofluid-reinforced blended fabric composite material is 15-40%, and the mass of the nanofluid is 1-4% of the mass of the phenolic resin matrix.

[0016] This invention provides a method for preparing the nano-fluid-reinforced blended fabric composite material described above, comprising the following steps:

[0017] The nanofluid is dispersed in a phenolic resin solution to obtain a phenolic resin mixed solution;

[0018] The PI / PTFE blended fabric is impregnated in the phenolic resin mixture solution and then dried to obtain the nano-fluid-reinforced blended fabric composite material.

[0019] This invention provides the application of the nanofluid-reinforced blended fabric composite material described in the above technical solutions or the nanofluid-reinforced blended fabric composite material prepared by the above technical solutions in the field of solid lubrication.

[0020] The present invention also provides a self-lubricating bearing material, comprising a support material and a blended fabric composite material bonded to the support material, wherein the blended fabric composite material is the nano-fluid-reinforced blended fabric composite material described in the above technical solutions or the nano-fluid-reinforced blended fabric composite material prepared by the preparation method described in the above technical solutions.

[0021] This invention provides a method for preparing Cu@Co MOF nanofluids. The method involves mixing a Cu-BTC metal-organic framework compound, an alcohol solvent, cobalt nitrate, and 2-methylimidazole for a self-assembly reaction to obtain a Cu@Co MOF hybrid. The Cu@Co MOF hybrid, an alcohol-water solvent, and dimethyloctadecyl[3-trimethoxysilylpropyl]ammonium chloride are then mixed for a dehydration condensation reaction to obtain a Cu@Co MOF-DC5700 precipitate. Finally, the Cu@Co MOF-DC5700 precipitate, an alcohol solvent, and polyethylene glycol 4-nonylphenyl-3-sulfopropyl ether potassium salt are mixed for an electrostatic assembly reaction to obtain the Cu@Co MOF nanofluid. This invention first grows Co-MOF material in situ on the surface of a Cu-BTC metal-organic framework compound to construct a Cu@Co MOF hybrid, serving as the core of a nanofluid-like structure. Then, an inner crown, dimethyloctadecyl[3-trimethoxysilylpropyl]ammonium chloride (DC-5700), is covalently grafted onto the surface of the Cu@Co MOF hybrid nanoparticles. Finally, an outer crown, polyethylene glycol 4-nonylphenyl-3-sulfopropyl ether potassium salt (PEGs), is combined with the inner crown via electrostatic adsorption to prepare the Cu@Co MOF nanofluid-like structure. The Cu@Co MOF nanofluid-like structure prepared in this invention exhibits good compatibility with the resin matrix of the blended fabric composite material, thus fully leveraging the synergistic reinforcing effect of Cu-BTC and Co-MOF. The introduction of the inner and outer crowns gives the Cu@Co MOF hybrid a fluid-like morphology, while also improving the quality of the transfer film during subsequent triboelectric transfer. Introducing the Cu@Co MOF nanofluid prepared in this invention as a nano-reinforcing agent into blended fabric composites can form a dense transfer film on the contact surface through electrostatic adsorption, molecular recombination and tribochemical reaction, thereby increasing the strength and extreme pressure resistance of the transfer film and significantly improving the tribological properties of the blended fabric composites.

[0022] The results of the examples show that, using the Cu@Co MOF nanofluid prepared in this invention as a reinforcing filler, the resulting reinforced blended fabric composite material has a friction coefficient of 0.047–0.055 and a wear volume of 6.54 × 10⁻⁶. -9 ~7.56×10 -9 m 3 The wear rate is 1.46 × 10⁻⁶. -14 ~1.69×10 -14 m 3 (N·m) -1 . Attached Figure Description

[0023] Figure 1Scanning and transmission electron microscopy images of Cu-BTC metal-organic framework compounds, Co MOF materials, and Cu@Co MOF hybrids prepared in Example 1. Figure 1 (a), (b), and (c) are scanning electron microscope (SEM) images of Cu-BTC metal-organic framework compound, CoMOF material, and Cu@Co MOF hybrid, respectively; (d), (e), and (f) are transmission electron microscope (TEM) images of Cu-BTC metal-organic framework compound, Co MOF material, and Cu@Co MOF hybrid, respectively; (f1) to (f4) are EDX-analytical elemental images of Cu@Co MOF hybrid.

[0024] Figure 2 This is a transmission electron microscope image of the Cu@Co MOF nanofluid in Example 1;

[0025] Figure 3 The infrared spectra of Cu@Co MOF nanofluid and Cu@Co MOF hybrid in Example 1 are shown.

[0026] Figure 4 The bar chart shows the wear rate and friction coefficient of the self-lubricating bearings in Comparative Example 1, Comparative Example 2, and Example 1.

[0027] Figure 5 The images show scanning electron microscope (SEM) images of the wear surfaces of the self-lubricating bearings in Comparative Examples 1, 2, and Example 1. Figure 5 In the figures, (a) is a scanning electron microscope (SEM) image of the wear surface of the self-lubricating bearing in Comparative Example 1; (b) is a SEM image of the wear surface of the self-lubricating bearing in Comparative Example 2; and (c) is a SEM image of the wear surface of the self-lubricating bearing in Example 1.

[0028] Figure 6 The images shown are transmission electron microscope (TEM) images and high-resolution TEM photographs of the triboelectric surface transfer film of the blended fabric composite material in Example 1. Figure 6 (a), (b), and (c) are transmission electron microscope (TEM) images, and (d) and (e) are high-resolution TEM images. Detailed Implementation

[0029] This invention provides a method for preparing Cu@Co MOF nanofluids, comprising the following steps:

[0030] (1) A Cu@Co MOF hybrid was obtained by mixing Cu-BTC metal-organic framework compound, alcohol solvent, cobalt nitrate and 2-methylimidazole and carrying out a self-assembly reaction.

[0031] (2) The Cu@Co MOF hybrid, alcohol-water solvent and dimethyloctadecyl[3-trimethoxysilylpropyl]ammonium chloride were mixed and subjected to dehydration condensation reaction to obtain Cu@Co MOF-DC5700 precipitate;

[0032] (3) The Cu@Co MOF-DC5700 precipitate, alcohol solvent and polyethylene glycol 4-nonylphenyl 3-sulfopropyl ether potassium salt were mixed and subjected to self-assembly reaction to obtain Cu@Co MOF nanofluid.

[0033] Unless otherwise specified, all raw materials involved in this invention are commercially available products well known to those skilled in the art.

[0034] This invention involves a self-assembly reaction of a Cu-BTC metal-organic framework compound, an alcohol solvent, cobalt nitrate, and 2-methylimidazole to obtain a Cu@Co MOF hybrid. This invention does not impose any particular requirements on the Cu-BTC metal-organic framework compound; it can be prepared using commercially available products or methods well-known to those skilled in the art. In the embodiments of this invention, the preferred method for preparing the Cu-BTC metal-organic framework compound is as follows: a hydrothermal reaction is carried out by mixing an aqueous solution of copper nitrate with a mixed solution of polyvinylpyrrolidone (PVP, acting as a surfactant) and trimesic acid; the resulting hydrothermal reaction solution is then sequentially filtered, washed with a solid phase, and dried to obtain the Cu-BTC metal-organic framework compound. In this invention, the concentration of the copper nitrate aqueous solution is preferably 0.1–0.3 g / mL, more preferably 0.1 g / mL; the mass ratio of copper nitrate to PVP and trimellitic acid in the copper nitrate aqueous solution is preferably 2:1:1; the solvent in the mixed solution of PVP and trimellitic acid is preferably a mixture of DMF and ethanol, the volume ratio of DMF to ethanol is preferably 1:1, and the concentrations of polyvinylpyrrolidone and trimellitic acid in the mixed solution of PVP and trimellitic acid are preferably 0.05 g / mL. In this invention, the mixing of the copper nitrate aqueous solution and the mixed solution of PVP and trimellitic acid is preferably by stirring. This invention does not have special requirements for the stirring conditions, as long as the components are mixed evenly. In this invention, the hydrothermal reaction temperature is preferably 90–120°C, more preferably 100–120°C, and the time is preferably 8–16 h, more preferably 12–16 h. This invention does not have special requirements for the methods of filtration, solid-phase washing, and drying; methods well known to those skilled in the art can be used.

[0035] In this invention, the preferred method for mixing the Cu-BTC metal-organic framework compound, the alcohol solvent, cobalt nitrate, and 2-methylimidazole is as follows: the Cu-BTC metal-organic framework compound is dispersed in a solvent, and then cobalt nitrate and 2-methylimidazole are added sequentially to the resulting dispersion, wherein the addition of cobalt nitrate and 2-methylimidazole is carried out under stirring conditions; the 2-methylimidazole is preferably added in the form of a 2-methylimidazole methanol solution. In this invention, the alcohol solvent is preferably methanol, and the concentration of the Cu-BTC metal-organic framework compound in the dispersion is preferably 0.01–0.03 g / mL, more preferably 0.01 g / mL; the mass ratio of the Cu-BTC metal-organic framework compound, cobalt nitrate, and 2-methylimidazole is preferably 1:1.5:(4–6). In this invention, the temperature of the self-assembly reaction is preferably room temperature, and the time is preferably 4–8 h, more preferably 6–8 h; the self-assembly reaction time is calculated from the point when the 2-methylimidazole is completely added; the self-assembly reaction is preferably carried out under stirring conditions. During the self-assembly reaction, Co-MOF material grows in situ on the surface of Cu-BTC metal-organic framework compound, forming a core-shell structure, namely the Cu@Co MOF hybrid. After the self-assembly reaction, the present invention preferably centrifuges, washes with a solid phase, and dries the resulting reaction solution sequentially to obtain the Cu@Co MOF hybrid.

[0036] After obtaining the Cu@Co MOF hybrid, the present invention involves mixing the Cu@Co MOF hybrid, an alcohol-water solvent, and dimethyloctadecyl[3-trimethoxysilylpropyl]ammonium chloride to undergo a dehydration condensation reaction to obtain the Cu@Co MOF-DC5700 precipitate. In the present invention, the preferred method for mixing the Cu@Co MOF hybrid, the alcohol-water solvent, and dimethyloctadecyl[3-trimethoxysilylpropyl]ammonium chloride is as follows: the Cu@Co MOF hybrid is dispersed in an alcohol-water solvent, and then dimethyloctadecyl[3-trimethoxysilylpropyl]ammonium chloride (DC-5700) is added dropwise to the resulting dispersion. In this invention, the alcohol in the alcohol-water solvent is preferably methanol, and the water is preferably deionized water, with a preferred volume ratio of methanol to deionized water of 9:1; the concentration of the Cu@Co MOF hybrid in the dispersion is preferably 0.01–0.03 g / mL, more preferably 0.02 g / mL; the ratio of Cu@Co MOF hybrid to DC-5700 is preferably 1 g:(2–3) mL, more preferably 1 g:2 mL. In this invention, the temperature of the dehydration condensation reaction is preferably room temperature, and the time is preferably 20–30 h, more preferably 20–24 h, calculated from the completion of DC-5700 addition; the dehydration condensation reaction is preferably carried out under stirring. During the dehydration condensation reaction, DC-5700 is dehydrated and covalently modified onto the surface of the Cu@Co MOF hybrid nanoparticles as an inner cap. After the dehydration condensation reaction, the present invention preferably centrifuges, washes with solid phase and dries the resulting reaction solution in sequence to obtain Cu@Co MOF-DC5700 precipitate.

[0037] After obtaining the Cu@Co MOF-DC5700 precipitate, the present invention performs an electrostatic assembly reaction by mixing the Cu@Co MOF-DC5700 precipitate, an alcohol solvent, and polyethylene glycol 4-nonylphenyl 3-sulfopropyl ether potassium salt (PEGs) to obtain Cu@Co MOF nanofluids. In the present invention, the preferred method for mixing the Cu@Co MOF-DC5700 precipitate, the alcohol solvent, and the PEGs is as follows: the Cu@Co MOF-DC5700 precipitate is dispersed in an alcohol solvent, and then PEGs are added to the resulting dispersion. In the present invention, the alcohol solvent is preferably methanol, the concentration of the Cu@Co MOF-DC5700 precipitate in the dispersion is preferably 0.01–0.05 g / mL, and the mass ratio of the Cu@Co MOF-DC5700 precipitate to PEGs is preferably 1:10–15, more preferably 1:10–12. In this invention, the preferred temperature for the electrostatic assembly reaction is 60–80°C, and the preferred time is 20–30 h, more preferably 20–24 h. The time for the electrostatic assembly reaction is calculated from the point when the PEGs are completely added. The electrostatic assembly reaction is preferably carried out under stirring conditions. During the electrostatic assembly reaction, the outer crown of polyethylene glycol 4-nonylphenyl 3-sulfopropyl ether potassium salt (PEGs) is bonded to the inner crown through electrostatic adsorption. After the electrostatic assembly reaction, the resulting reaction solution is preferably centrifuged, washed with solid phase, and dried to obtain Cu@Co MOF nanofluids.

[0038] This invention provides Cu@Co MOF nanofluids prepared by the above-described technical solution. The Cu@Co MOF nanofluids include a Cu@Co MOF hybrid core and an inner crown and an outer crown grafted sequentially from the inside to the outside onto the surface of the Cu@Co MOF hybrid core. The Cu@Co MOF hybrid core has a core-shell structure, including a Cu-BTC metal-organic framework compound and a Co-MOF material grown in situ on the surface of the Cu-BTC metal-organic framework compound. The inner crown is dimethyloctadecyl[3-trimethoxysilylpropyl]ammonium chloride, and the outer crown is polyethylene glycol 4-nonylphenyl 3-sulfopropyl ether potassium salt.

[0039] This invention provides the application of Cu@Co MOF nanofluids as nano-reinforcing agents in blended fabric composites. This invention constructs a hybrid core using a combination of Cu-BTC and Co-MOF materials, and connects an inner crown (DC-5700) and an outer crown (PEGs) to obtain Cu@Co MOF nanofluids. Using these as nano-reinforcing agents in blended fabric composites, the monodispersity of the nanofluids makes it easier to obtain uniformly dispersed nanocomposite materials, thereby leveraging the excellent physicochemical properties of the nanoparticles. Furthermore, the shell organic molecular structure of the Cu@Co MOF nanofluids is closely related to the adsorption film structure and tribochemical interactions at the friction surface, while the structure and properties of the nanocore can affect the load-bearing capacity of the transfer film. This invention, by using Cu@Co MOF nanofluids with specific core, inner crown, and outer crown structures as nano-reinforcing agents in textile composites, enables the regulation of the properties of the fabric composite material and the structure of the transfer film, effectively improving the tribological properties of the fabric composite material.

[0040] This invention provides a nanofluid-reinforced blended fabric composite material, comprising a PI / PTFE blended fabric and a phenolic resin material attached to the surface and interior of the PI / PTFE blended fabric; the phenolic resin material comprises a phenolic resin matrix and a nanofluid, wherein the nanofluid is the Cu@Co MOF nanofluid described in the above technical solution. This invention does not have special requirements for the PI / PTFE blended fabric; any PI / PTFE blended fabric well known to those skilled in the art can be used. In this invention, the mass content of the phenolic resin matrix in the nanofluid-reinforced blended fabric composite material is preferably 15-40%, more preferably 25-30%, and even more preferably 27-30%; the mass of the nanofluid is preferably 1-4% of the mass of the phenolic resin matrix, preferably 2-3%. In this invention, the Cu@Co MOF nanofluid exhibits excellent compatibility with phenolic resin, thus fully leveraging its reinforcing properties. When the Cu@Co MOF nanofluid is introduced into the blended fabric composite material, a dense transfer film is formed on the contact surface through electrostatic adsorption, molecular recombination, and tribochemical reactions. This increases the strength and extreme pressure resistance of the transfer film, thereby significantly improving the tribological properties of the blended fabric composite material. The nanofluid-reinforced blended fabric composite material provided by this invention possesses excellent friction and wear resistance.

[0041] This invention provides a method for preparing the nano-fluid-reinforced blended fabric composite material described above, comprising the following steps:

[0042] The nanofluid is dispersed in a phenolic resin solution to obtain a phenolic resin mixed solution;

[0043] The PI / PTFE blended fabric is impregnated in the phenolic resin mixture solution and then dried to obtain the nano-fluid-reinforced blended fabric composite material.

[0044] In this invention, the phenolic resin solution is specifically obtained by dissolving phenolic resin in an organic solvent; the organic solvent is preferably a mixed solvent of ethanol, acetone, and ethyl acetate, and the volume ratio of ethanol, acetone, and ethyl acetate in the mixed solvent is preferably (0.5-1):(0.5-1):(0.5-1); the volume ratio of phenolic resin to organic solvent is preferably 1 g:(5-10) mL. In this invention, the mass of the nanofluid in the phenolic resin mixed solution is preferably 1-4% of the mass of the phenolic resin. This invention does not have special requirements on the amount of the phenolic resin mixed solution used, as long as it is sufficient to fully impregnate the PI / PTFE blended fabric. In the embodiments of this invention, the size of the PI / PTFE blended fabric is 3.5 cm × 10.5 cm, and the volume of the phenolic resin mixed solution is 80-200 mL. In this invention, the drying temperature is preferably 40-80°C, more preferably 50-70°C; the impregnation and drying are preferably repeated until the mass content of phenolic resin in the nano-fluid-reinforced blended fabric composite material meets the above requirements, wherein the time for a single impregnation is preferably 1-2 min, and the time for a single drying is preferably 5-30 min, more preferably 10-20 min.

[0045] This invention provides the application of the nanofluid-reinforced blended fabric composite material described in the above technical solutions or the nanofluid-reinforced blended fabric composite material prepared by the above technical solutions in the field of solid lubrication.

[0046] This invention also provides a self-lubricating bearing material, comprising a support material and a blended fabric composite material bonded to the support material. The blended fabric composite material is the nano-fluid-reinforced blended fabric composite material described in the above technical solutions or the nano-fluid-reinforced blended fabric composite material prepared by the preparation method described in the above technical solutions. In this invention, the support material is preferably made of metal; the metal preferably includes 9Cr18, GCr15, or 17-4PH, more preferably 9Cr18 or 17-4PH. This invention preferably uses a phenolic resin adhesive to bond the blended fabric composite material to the surface of the support material, and then performs a curing reaction under certain temperature and pressure conditions to obtain the self-lubricating bearing material. This invention does not specifically limit the amount of phenolic resin adhesive used, as long as it can bond the support material and the blended fabric composite material together. In this invention, the curing pressure is preferably 0.5–3 MPa, more preferably 1–2 MPa; the curing includes a first curing and a second curing performed sequentially. The temperature of the first curing is preferably 150°C, the holding time is preferably 30–60 min, more preferably 40–50 min, and the time to rise from room temperature to the first curing temperature is preferably 30–60 min, more preferably 50 min; the temperature of the second curing is preferably 180°C, the holding time is preferably 100–140 min, more preferably 100–120 min, and the time to rise from the first curing temperature to the second curing temperature is preferably 30 min. This invention divides the curing process into two temperature stages, sequentially performing preliminary curing and deep curing, which avoids excessively rapid heating leading to a rapid curing reaction and the formation of numerous pores within the resin.

[0047] To further illustrate the present invention, the Cu@Co MOF nanofluid-like composite material and nanofluid-like reinforced blended fabric composite material, as well as their preparation and application, are described in detail below with reference to examples. However, these descriptions should not be construed as limiting the scope of protection of the present invention.

[0048] Example 1

[0049] The preparation method of Cu@Co MOF nanofluids is as follows:

[0050] A copper nitrate aqueous solution (0.1 g / mL, 40 mL) was mixed with a DMF / ethanol mixture of polyvinylpyrrolidone (PVP) (0.05 g / mL) and tricresylbenzene (0.05 g / mL) (V). DMF V 乙醇 =1:1, 40mL) were mixed evenly, then transferred to a hydrothermal reactor and hydrothermally reacted at 100℃ for 12h. After filtration, washing and drying, Cu-BTC metal-organic framework compound was obtained.

[0051] The Cu-BTC metal-organic framework compound (0.2 g) obtained above was dispersed in methanol solution (20 mL) and ultrasonically dispersed for 5 min. Then, cobalt nitrate (0.3 g) was added and stirred continuously. Then, 2-methylimidazole (0.8 g) methanol solution (20 mL) was added to the above solution and stirred continuously at room temperature for 6 h. After centrifugation, washing and drying, Cu@Co MOF hybrid was obtained. Co MOF material was grown in situ on the surface of Cu-BTC compound to form a core-shell structure.

[0052] The obtained Cu@Co MOF hybrid (1g) was dispersed in a mixed solution (50mL) of methanol / deionized water (V methanol:V deionized water = 9:1), and then 2mL of dimethyloctadecyl[3-trimethoxysilylpropyl]ammonium chloride (DC-5700) was added dropwise. The mixture was stirred at room temperature for 24h to obtain Cu@Co MOF-DC5700 precipitate after centrifugation, washing and drying.

[0053] 1 g of Cu@Co MOF-DC5700 precipitate was dispersed in 20 mL of methanol solution, and then 10 g of polyethylene glycol 4-nonylphenyl 3-sulfopropyl ether potassium salt (PEGs) was added. The mixture was stirred at 60 °C for 24 h. The mixture was then centrifuged, washed, and dried to obtain Cu@Co MOF nanofluid.

[0054] The preparation method of the nanofluid-reinforced blended fabric composite material is as follows:

[0055] The PI / PTFE blended fabric was repeatedly impregnated and dried in a phenolic resin solution containing Cu@Co MOF nanofluid (each drying temperature controlled at 50℃ for 15 min) to obtain a Cu@Co MOF nanofluid-reinforced PI / PTFE blended fabric composite material (i.e., phenolic resin-based composite material); the mass fraction of Cu@Co MOF nanofluid in the phenolic resin matrix was 3 wt%; and the mass fraction of phenolic resin in the PI / PTFE blended fabric reinforced resin composite material was 27%.

[0056] A self-lubricating bearing material, prepared by the following method:

[0057] The obtained nano-fluid-reinforced blended fabric composite material was bonded to the surface of a metal substrate (9Cr18) using a phenolic resin adhesive. Under a pressure of 2 MPa, the temperature was increased from room temperature to 150°C in 50 min, held at 150°C for 30 min, increased from 150°C to 180°C in 30 min, and held at 180°C for 140 min to obtain a self-lubricating bearing material.

[0058] Example 2

[0059] The preparation method of Cu@Co MOF nanofluids is as follows:

[0060] A copper nitrate aqueous solution (0.1 g / mL, 50 mL) was mixed with a DMF / ethanol mixture of polyvinylpyrrolidone (PVP) (0.05 g / mL) and tricresylbenzene (0.05 g / mL) (V). DMF V 乙醇 =1:1, 50mL) Mix evenly, then transfer to a hydrothermal reactor and react hydrothermally at 120℃ for 12h. After filtration, washing and drying, Cu-BTC metal-organic framework compound is obtained.

[0061] The Cu-BTC metal-organic framework compound (0.3 g) obtained above was dispersed in methanol solution (30 mL) and ultrasonically dispersed for 5 min. Then, cobalt nitrate (0.45 g) was added and stirred continuously. Then, 2-methylimidazole (1.2 g) methanol solution (30 mL) was added to the above solution and stirred continuously at room temperature for 6 h. After centrifugation, washing and drying, Cu@Co MOF hybrid was obtained. Co MOF material was grown in situ on the surface of Cu-BTC compound to form a core-shell structure.

[0062] The obtained Cu@Co MOF hybrid (1 g) was dispersed in methanol / deionized water (V... 甲醇 V 去离子水 In a 9:1 mixture (50 mL), 2 mL of dimethyloctadecyl[3-trimethoxysilylpropyl]ammonium chloride (DC-5700) was added dropwise. The mixture was stirred at room temperature for 24 h. The Cu@Co MOF-DC5700 precipitate was obtained by centrifugation, washing, and drying.

[0063] 1 g of Cu@Co MOF-DC5700 precipitate was dispersed in 20 mL of methanol solution, and then 10 g of polyethylene glycol 4-nonylphenyl 3-sulfopropyl ether potassium salt (PEGs) was added. The mixture was stirred at 60 °C for 24 h. The mixture was then centrifuged, washed, and dried to obtain Cu@Co MOF nanofluid.

[0064] The preparation method of the nanofluid-reinforced blended fabric composite material is as follows:

[0065] PI / PTFE blended fabrics were repeatedly impregnated and dried in a phenolic resin solution containing Cu@Co MOF nanofluids (each drying temperature controlled at 50℃ for 15 min) to obtain Cu@Co MOF nanofluid-reinforced PI / PTFE blended fabric composites (i.e., phenolic resin-based composites); the mass fraction of Cu@Co MOF nanofluids in the phenolic resin matrix was 3 wt%; and the mass fraction of phenolic resin in the PI / PTFE fabric-reinforced resin composite was 27%.

[0066] A self-lubricating bearing material, prepared by the following method:

[0067] The obtained fabric-reinforced resin composite material was bonded to the surface of a metal substrate (9Cr18) using a phenolic resin adhesive. Under a pressure of 2 MPa, the temperature was increased from room temperature to 150°C in 50 min, held at 150°C for 30 min, increased from 150°C to 180°C in 30 min, and held at 180°C for 140 min to obtain a self-lubricating bearing material.

[0068] Example 3

[0069] The preparation method of Cu@Co MOF nanofluids is as follows:

[0070] A copper nitrate aqueous solution (0.1 g / mL, 60 mL) was mixed with a DMF / ethanol mixture of polyvinylpyrrolidone (PVP) (0.05 g / mL) and tricresylbenzene (0.05 g / mL) (V). DMF V 乙醇 =1:1, 60mL) Mix evenly, then transfer to a hydrothermal reactor and react hydrothermally at 100℃ for 12h. After filtration, washing and drying, Cu-BTC metal-organic framework compound is obtained.

[0071] The Cu-BTC metal-organic framework compound (0.2 g) obtained above was dispersed in methanol solution (20 mL) and ultrasonically dispersed for 5 min. Then, cobalt nitrate (0.3 g) was added and stirred continuously. Then, 2-methylimidazole (0.8 g) methanol solution (20 mL) was added to the above solution and stirred continuously at room temperature for 6 h. The resulting precipitate was centrifuged, washed and dried to obtain Cu@CoMOF hybrid. Co MOF material was grown in situ on the surface of Cu-BTC compound to form a core-shell structure.

[0072] The obtained Cu@Co MOF hybrid (1 g) was dispersed in methanol / deionized water (V... 甲醇 V 去离子水 In a 9:1 mixture (50 mL), 2 mL of dimethyloctadecyl[3-trimethoxysilylpropyl]ammonium chloride (DC-5700) was added dropwise. The mixture was stirred at room temperature for 24 h. After centrifugation, washing, and drying, Cu@Co MOF-DC5700 precipitate was obtained.

[0073] 1 g of Cu@Co MOF-DC5700 precipitate was dispersed in 20 mL of methanol solution, and then 10 g of polyethylene glycol 4-nonylphenyl 3-sulfopropyl ether potassium salt (PEGs) was added. The mixture was stirred at 60 °C for 24 h. The mixture was then centrifuged, washed, and dried to obtain Cu@Co MOF nanofluid.

[0074] The preparation method of the nanofluid-reinforced blended fabric composite material is as follows:

[0075] The PI / PTFE blended fabric was repeatedly impregnated and dried in a phenolic resin solution containing Cu@Co MOF nanofluid (each drying temperature controlled at 50℃ for 15 min) to obtain a Cu@Co MOF nanofluid-reinforced PI / PTFE blended fabric composite material (i.e., phenolic resin-based composite material); the mass fraction of Cu@Co MOF nanofluid in the phenolic resin matrix was 2 wt%; and the mass fraction of phenolic resin in the PI / PTFE fabric-reinforced resin composite material was 27%.

[0076] A self-lubricating bearing material, prepared by the following method:

[0077] The obtained fabric-reinforced resin composite material was bonded to the surface of a metal substrate (9Cr18) using a phenolic resin adhesive. Under a pressure of 2 MPa, the temperature was increased from room temperature to 150°C in 50 min, held at 150°C for 30 min, increased from 150°C to 180°C in 30 min, and held at 180°C for 140 min to obtain a self-lubricating bearing material.

[0078] Example 4

[0079] The preparation method of Cu@Co MOF nanofluids is as follows:

[0080] A copper nitrate aqueous solution (0.1 g / mL, 40 mL) was mixed with a DMF / ethanol mixture of polyvinylpyrrolidone (PVP) (0.05 g / mL) and tricresylbenzene (0.05 g / mL) (V). DMF V 乙醇 =1:1, 40mL) were mixed evenly, then transferred to a hydrothermal reactor and hydrothermally reacted at 100℃ for 12h. After filtration, washing and drying, Cu-BTC metal-organic framework compound was obtained.

[0081] The Cu-BTC compound (0.2 g) obtained above was dispersed in methanol solution (20 mL) and ultrasonically dispersed for 5 min. Then, cobalt nitrate (0.3 g) was added and stirred continuously. Then, 2-methylimidazole (0.8 g) methanol solution (20 mL) was added to the above solution and stirred continuously at room temperature for 6 h. After centrifugation, washing and drying, Cu@Co MOF hybrid was obtained. Co MOF material was grown in situ on the surface of Cu-BTC compound to form a core-shell structure.

[0082] The obtained Cu@Co MOF hybrid (1 g) was dispersed in methanol / deionized water (V... 甲醇 V 去离子水In a 9:1 mixture (50 mL), 2 mL of dimethyloctadecyl[3-trimethoxysilylpropyl]ammonium chloride (DC-5700) was added dropwise. The mixture was stirred at room temperature for 24 h. After centrifugation, washing, and drying, Cu@Co MOF-DC5700 precipitate was obtained.

[0083] 1g of Cu@Co MOF-DC5700 was dispersed in 20mL of methanol solution, and then 10g of polyethylene glycol 4-nonylphenyl 3-sulfopropyl ether potassium salt (PEGs) was added. The mixture was stirred at 60℃ for 24h. The mixture was then centrifuged, washed, and dried to obtain Cu@Co MOF nanofluid.

[0084] The preparation method of the nanofluid-reinforced blended fabric composite material is as follows:

[0085] PI / PTFE blended fabrics were repeatedly impregnated and dried in a phenolic resin solution containing Cu@Co MOF nanofluids (each drying temperature controlled at 50℃ for 15 min) to obtain Cu@Co MOF nanofluid-reinforced PI / PTFE blended fabric composites (i.e., phenolic resin-based composites); the mass fraction of Cu@Co MOF nanofluids in the phenolic resin matrix was 1 wt%; and the mass fraction of phenolic resin in the PI / PTFE fabric-reinforced resin composites was 30%.

[0086] A self-lubricating bearing material, prepared by the following method:

[0087] The obtained fabric-reinforced resin composite material was bonded to the surface of a metal substrate (9Cr18) using a phenolic resin adhesive. Under a pressure of 2 MPa, the temperature was increased from room temperature to 150°C in 50 min, held at 150°C for 30 min, increased from 150°C to 180°C in 30 min, and held at 180°C for 140 min to obtain a self-lubricating bearing material.

[0088] Comparative Example 1

[0089] PI / PTFE blended fabric reinforced phenolic resin-based composite material was prepared according to the preparation method of Example 1, except that Cu@Co MOF nanofluid was not added to the phenolic resin solution.

[0090] Comparative Example 2

[0091] PI / PTFE blended fabric reinforced phenolic resin-based composite material was prepared according to the preparation method of Example 1, except that Cu@Co MOF nano-hybrids were added to the phenolic resin solution.

[0092] The morphologies of the Cu-BTC metal-organic framework compound, Co MOF material, and Cu@Co MOF hybrid prepared in Example 1 were characterized, and scanning electron microscope and transmission electron microscope images were obtained, as shown below. Figure 1 As shown. Figure 1 Images (a), (b), and (c) are scanning electron microscope (SEM) images of Cu-BTC metal-organic framework compounds, Co MOF materials, and Cu@Co MOF hybrids, respectively; images (d), (e), and (f) are transmission electron microscope (TEM) images of Cu-BTC metal-organic framework compounds, Co MOF materials, and Cu@Co MOF hybrids, respectively; images (f1) to (f4) are EDX-analytical elemental images of Cu@Co MOF hybrids. Figure 1 It can be clearly seen that the Co MOF material is uniformly coated on the surface of the Cu-BTC compound, forming a core-shell structure.

[0093] The morphology of the Cu@Co MOF nanofluid prepared in Example 1 was characterized, and transmission electron microscopy images were obtained, as shown below. Figure 2 As shown. By Figure 2 As can be seen, the morphology of the Cu@Co MOF nanofluid is similar to that of the Cu@Co MOF hybrid, except that it is coated with a translucent material. Figure 3 The infrared spectrum shows that, compared to the Cu@Co MOF hybrid, Cu@Co MOF nanofluids ( Figure 3 The Cu@CoPLs (as shown) exhibits a stretching vibration peak in saturated alkanes (2873 cm⁻¹). -1 ), stretching vibration peak of benzene ring (1609 cm⁻¹) -1 1467cm -1 ), and the characteristic absorption peak of sulfonic acid groups (1242 cm⁻¹). -1 This indicates that DC-5700 and PEGs were successfully grafted onto the surface of the Cu@Co MOF hybrid to prepare Cu@Co MOF nanofluids.

[0094] Using 45# steel with a diameter of 2mm as the friction pair, the friction and wear performance of self-lubricating bearings prepared using PI / PTFE blended fabric reinforced resin composites from Examples 1-4 and PI / PTFE blended fabric reinforced phenolic resin composites from Comparative Examples 1-2 was tested at room temperature under the following conditions: applied load of 75MPa (240N), friction rotation speed of 0.26m / s, friction time of 120min, and radius of 12.5mm. The results are listed in Table 1. The friction coefficient was automatically output by processing the collected data through a connected computer. The wear depth of the wear-resistant material was measured using a digital height gauge, and the wear volume of the fabric composite was calculated. The wear rate of the wear-resistant material was calculated according to Formula 1.

[0095] K = ΔV / P˙L (Formula 1)

[0096] Where K is the wear rate (m 3 (N˙m) -1 ); ΔV is the wear volume (m³). 3 P is the applied load (N); L is the sliding distance (m); where L = v * t (v is the frictional rotational speed, t is the friction time).

[0097] Table 1. Friction and wear properties of self-lubricating bearings in Examples 1-4 and Comparative Examples 1-2

[0098]

[0099]

[0100] Figure 4 The wear rate and friction coefficient of the self-lubricating bearings in Comparative Example 1, Comparative Example 2 and Example 1 are shown in histograms.

[0101] Combining Table 1 and Figure 4 It can be seen that, compared with Comparative Example 1, the wear rate and friction coefficient of the self-lubricating bearing in Example 1 were reduced by 164% and 66%, respectively. This indicates that the introduction of Cu@Co MOF nanofluid effectively improves the tribological properties of the self-lubricating bearing made of PI / PTFE blended fabric composite material.

[0102] After conducting friction tests on the self-lubricating bearings of Comparative Examples 1, 2, and Example 1 according to the above method, the surface morphology of the worn surfaces was inspected, and scanning electron microscope images were obtained, as shown below. Figure 5 As shown. Figure 5 In the images, (a) is a scanning electron microscope (SEM) image of the worn surface of the self-lubricating bearing in Comparative Example 1; (b) is a SEM image of the worn surface of the self-lubricating bearing in Comparative Example 2; and (c) is a SEM image of the worn surface of the self-lubricating bearing in Example 1. Figure 5 It can be seen that the wear surfaces of Comparative Examples 1 and 2 are relatively rough, the resin matrix on the fiber surface is peeled off, and the internal reinforcing fibers are destroyed; while the wear surface of Example 1 is relatively smooth, which further illustrates that the Cu@Co MOF nanofluid-like reinforced PI / PTFE blended phenolic resin matrix composite material provided by the present invention has high tribological properties.

[0103] As can be seen from the above examples, Cu@Co MOF nanofluids exhibit excellent compatibility with the composite resin matrix due to their unique physicochemical properties, thus fully leveraging the reinforcing properties of nanofluids. When Cu@Co MOF nanofluids are introduced into blended fabric composites, a dense transfer film is formed on the contact surface through electrostatic adsorption, molecular recombination, and tribochemical reactions. This increases the strength and extreme pressure resistance of the transfer film, thereby significantly improving the tribological properties of the blended fabric composite. The transfer film on the mating surface was processed using a focused ion beam, and its structure was investigated using transmission electron microscopy. The study shows that the introduction of Cu@Co MOF nanofluids forms FeF2, Fe2O3, FeO (0.266nm, 0.287nm, 0.298nm) and CuO, Cu2O, Co3O4 (0.232nm, 0.246nm, 0.210nm) substances on the mating surface, effectively improving the strength and extreme pressure resistance of the tribochemical transfer film (e.g., ...). Figure 6 As shown, Figure 6 The images shown are transmission electron microscope (TEM) images and high-resolution TEM photographs of the triboelectric surface transfer film of the blended fabric composite material in Example 1. Figure 6 (a), (b), and (c) are transmission electron microscopy (TEM) images, and (d) and (e) are high-resolution TEM images. The numbers in the images represent the lattice fringe spacing, indicating that the tribochemical process generates new substances.

[0104] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles 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 Cu@CoMOF nanofluids, comprising the following steps: (1) A Cu@CoMOF hybrid was obtained by mixing Cu-BTC metal-organic framework compound, alcohol solvent, cobalt nitrate and 2-methylimidazole and carrying out a self-assembly reaction. (2) The Cu@CoMOF hybrid, alcohol-water solvent and dimethyloctadecyl[3-trimethoxysilylpropyl]ammonium chloride were mixed and subjected to a dehydration condensation reaction to obtain Cu@CoMOF-DC5700 precipitate; (3) The Cu@CoMOF-DC5700 precipitate, alcohol solvent and polyethylene glycol 4-nonylphenyl 3-sulfopropyl ether potassium salt were mixed and subjected to electrostatic assembly reaction to obtain Cu@CoMOF nanofluid.

2. The preparation method according to claim 1, characterized in that, In step (1), the mass ratio of Cu-BTC metal-organic framework compound, cobalt nitrate and 2-methylimidazole is 1:1.5:(4-6); the self-assembly reaction is carried out at room temperature for 4-8 hours.

3. The preparation method according to claim 1, characterized in that, In step (2), the ratio of Cu@CoMOF hybrid to dimethyloctadecyl[3-trimethoxysilylpropyl]ammonium chloride is 1 g: (2-3) mL; the dehydration condensation reaction is carried out at room temperature for 20-30 h.

4. The preparation method according to claim 1, characterized in that, In step (3), the mass ratio of Cu@CoMOF-DC5700 precipitate to polyethylene glycol 4-nonylphenyl 3-sulfopropyl ether potassium salt is 1:10-15; the electrostatic assembly reaction is carried out at a temperature of 60-80°C for 20-30 hours.

5. The Cu@CoMOF nanofluid obtained by the preparation method according to any one of claims 1 to 4, wherein the Cu@CoMOF nanofluid comprises a Cu@CoMOF hybrid core and an inner crown and an outer crown grafted sequentially from the inside to the outside onto the surface of the Cu@CoMOF hybrid core; the Cu@CoMOF hybrid core has a core-shell structure, comprising a Cu-BTC metal-organic framework compound and a Co-MOF material grown in situ on the surface of the Cu-BTC metal-organic framework compound; the inner crown is dimethyloctadecyl[3-trimethoxysilylpropyl]ammonium chloride, and the outer crown is polyethylene glycol 4-nonylphenyl 3-sulfopropyl ether potassium salt.

6. The application of the Cu@CoMOF nanofluid as described in claim 5 as a nano-reinforcing agent for blended fabric composites.

7. A nanofluid-reinforced blended fabric composite material, characterized in that, The composite material includes a PI / PTFE blended fabric and a phenolic resin material attached to the surface and interior of the PI / PTFE blended fabric; the phenolic resin material includes a phenolic resin matrix and a nanofluid, wherein the nanofluid is the Cu@CoMOF nanofluid as described in claim 5; the phenolic resin matrix in the nanofluid-reinforced blended fabric composite material has a mass content of 15-40%, and the mass of the nanofluid is 1-4% of the mass of the phenolic resin matrix.

8. The method for preparing the nanofluid-reinforced blended fabric composite material according to claim 7, characterized in that, Includes the following steps: The nanofluid is dispersed in a phenolic resin solution to obtain a phenolic resin mixed solution; The PI / PTFE blended fabric is impregnated in the phenolic resin mixture solution and then dried to obtain the nano-fluid-reinforced blended fabric composite material.

9. The application of the nanofluid-reinforced blended fabric composite material according to claim 7 or the nanofluid-reinforced blended fabric composite material prepared by the preparation method according to claim 8 in the field of solid lubrication.

10. A self-lubricating bearing material, characterized in that, The composite material includes a support material and a blended fabric bonded to the support material, wherein the blended fabric is the nanofluid-reinforced blended fabric as described in claim 7 or the nanofluid-reinforced blended fabric prepared by the preparation method described in claim 8.

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