MXene-Ag Co-Modified PI / PTFE Blended Fabric, Phenolic Resin-Based Composite Material, and Preparation and Application

Abstract

The present invention provides an MXene-Ag combined modified PI / PTFE blended fabric, a phenolic resin-based composite material, a preparation method and an application, relating to the technical field of solid lubricating materials. Through the combined modification of MXene nanosheets and Ag nanoparticles, the surface roughness and the content of active groups of the PI / PTFE blended fabric are significantly increased, promoting the interfacial interlocking and chemical bonding between the blended fabric and the phenolic resin matrix, and effectively improving the interfacial adhesion performance of the fabric composite material; moreover, after being compounded with the phenolic resin, the MXene nanosheets and Ag nanoparticles present at the interface of the PI / PTFE blended fabric composite material can be released to the friction interface during the friction process and participate in the construction of a high-quality friction transfer film, solving the defect of the weak bonding force between the original PTFE transfer film and the counterpart, and effectively improving the friction and wear performance of the PI / PTFE blended fabric reinforced phenolic resin-based composite material.

Description

Technical Field

[0001] The present invention relates to the technical field of solid lubricant materials, and particularly to MXene-Ag co-modified PI / PTFE blended fabric, phenolic resin-based composite material, preparation method and application thereof. Background Art

[0002] PI / PTFE (polyimide / polytetrafluoroethylene) blended fabric combines the outstanding mechanical properties and heat resistance of PI fibers and the excellent lubricating properties of polytetrafluoroethylene fibers, making the prepared PI / PTFE phenolic resin-based composite material exhibit good wear-resistant and lubricating properties. However, due to the high degree of crystallinity and orientation on the surfaces of PI fibers and PTFE fibers, the fiber surfaces are smooth and lack effective active groups, making it difficult to form an effective interfacial bonding effect between the PI / PTFE blended fabric and the resin matrix. In addition, although PTFE fibers are relatively easy to transfer to the counter surface during friction, showing a low friction coefficient, the binding force between the PTFE transfer film and the counter surface is weak, resulting in rapid transfer and shedding of the PI / PTFE blended fabric composite material during friction, causing serious wear. Especially in the face of extreme operating conditions, the PI / PTFE blended fabric composite material often fails due to serious resin shedding and fiber pulling out problems. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide MXene-Ag co-modified PI / PTFE blended fabric, phenolic resin-based composite material, preparation method and application thereof. The MXene-Ag co-modified PI / PTFE blended fabric provided by the present invention reinforces phenolic resin, has good interfacial bonding properties with the phenolic resin matrix, and the tribological properties of the obtained phenolic resin composite material are significantly improved.

[0004] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0005] The present invention provides an MXene-Ag co-modified PI / PTFE blended fabric, comprising a PI / PTFE blended fabric, a polydopamine transition layer compounded on the surface of the PI / PTFE blended fabric, and MXene thin nanosheets adsorbed on the surface of the PI / PTFE blended fabric through hydrogen bonding with the polydopamine transition layer; Ag nanoparticles are in-situ loaded on the surface of the MXene thin nanosheets.

[0006] The present invention provides a preparation method of the MXene-Ag co-modified PI / PTFE blended fabric as described in the above technical solution, comprising the following steps:

[0007] (1) Mix the PI / PTFE blended fabric, Tris-HCl buffer solution of dopamine hydrochloride, catalyst and oxidant to carry out an oxidative self-polymerization reaction to obtain a polydopamine-modified PI / PTFE blended fabric;

[0008] (2) Mix the polydopamine-modified PI / PTFE blended fabric with the MXene thin-layer nanosheet aqueous dispersion to obtain an MXene nanosheet-modified PI / PTFE blended fabric;

[0009] (3) Mix the MXene nanosheet-modified PI / PTFE blended fabric with an AgNO 3 aqueous solution to carry out an in-situ reduction reaction of Ag + to obtain the MXene-Ag co-modified PI / PTFE blended fabric.

[0010] Preferably, in the step (1), the concentration of dopamine hydrochloride in the Tris-HCl buffer solution of dopamine hydrochloride is 1-3 mg / mL; the catalyst is CuSO 4 , and the oxidant is H 2 O 2 ; the dosage ratio of the catalyst to the Tris-HCl buffer solution of dopamine hydrochloride is 4-6 mmol: 1 L; the molar ratio of the oxidant to the catalyst is 4-6: 1.

[0011] Preferably, the time of the oxidative self-polymerization reaction in the step (1) is 0.5-2 h.

[0012] Preferably, in the step (2), the concentration of MXene thin-layer nanosheets in the MXene thin-layer nanosheet aqueous dispersion is 1-3 mg / mL, the mixing time is 1-2 h, and the mixing is carried out under stirring conditions.

[0013] Preferably, in the step (3), the concentration of AgNO 3 in the AgNO 3 aqueous solution is 1-4 mg / mL, the time of the in-situ reduction reaction of Ag + is 0.5-1 h, and the in-situ reduction reaction of Ag + is carried out under stirring conditions.

[0014] The present invention provides a phenolic resin-based composite material, which includes the MXene-Ag co-modified PI / PTFE blended fabric described in the above technical solution or the MXene-Ag co-modified PI / PTFE blended fabric prepared by the preparation method described in the above technical solution, and phenolic resin attached to the surface and inside of the MXene-Ag co-modified PI / PTFE blended fabric; the mass percentage content of phenolic resin in the phenolic resin-based composite material is 15-40%.

[0015] The present invention provides a method for preparing the phenolic resin-based composite material described in the above technical solution, including the following steps:

[0016] The MXene-Ag combined modified PI / PTFE blended fabric is impregnated with a phenolic resin dispersion and then dried to obtain the phenolic resin-based composite material.

[0017] The present invention provides the application of the phenolic resin-based composite material described in the above technical solution or the phenolic resin-based composite material prepared by the preparation method described in the above technical solution in the field of solid lubrication.

[0018] The present invention provides a self-lubricating bearing material, including a support material and a phenolic resin-based composite material bonded to the support material, and the phenolic resin-based composite material is the phenolic resin-based composite material described in the above technical solution or the phenolic resin-based composite material prepared by the preparation method described in the above technical solution.

[0019] The present invention provides an MXene-Ag combined modified PI / PTFE blended fabric, including a PI / PTFE blended fabric, a polydopamine transition layer compounded on the surface of the PI / PTFE blended fabric, and MXene thin-layer nanosheets adsorbed on the surface of the PI / PTFE blended fabric through hydrogen bonding with the polydopamine transition layer; Ag nanoparticles are in-situ loaded on the surface of the MXene thin-layer nanosheets. Through the combined modification of MXene nanosheets and Ag nanoparticles, the present invention significantly increases the surface roughness and the content of active groups of the PI / PTFE blended fabric, promotes the interfacial interlocking and chemical bonding between the blended fabric and the phenolic resin matrix, and effectively improves the interfacial adhesion performance of the fabric composite material; moreover, after being compounded with the phenolic resin, the MXene nanosheets and Ag nanoparticles existing at the interface of the PI / PTFE blended fabric composite material can be released to the friction interface during the friction process and participate in the construction of a high-quality friction transfer film, solving the defect of weak bonding force between the original PTFE transfer film and the counterbody, and effectively improving the friction and wear performance of the PI / PTFE blended fabric reinforced phenolic resin-based composite material.

[0020] The results of the examples show that when the MXene-Ag combined modified PI / PTFE blended fabric provided by the present invention is used to reinforce phenolic resin, the friction coefficient of the obtained phenolic resin-based composite material is 0.050 - 0.052, and the wear volume is 8.4×10 -9 ~9.4×10 -9 m 3 , and the wear rate is 1.86×10 -14 ~2.10×10 -14 m 3 (N·m)-1 。 Description of the Drawings

[0021] Figure 1 It is a scanning electron microscope photograph of the MXene nanosheets prepared in Example 1. Figure 1 In it, the left figure is Ti 3 AlC 2 The scanning electron microscope photograph of the product after etching the powder with hydrofluoric acid solution, and the right figure is Ti 3 AlC 2 The scanning electron microscope photograph of the MXene thin-layer nanosheet material obtained after etching and exfoliating the powder;

[0022] Figure 2 It is the scanning electron microscope photographs of the PI fibers in Comparative Example 1 and Examples 1 to 3. Figure 2 In it, (a) is the morphology of the PI fiber in Comparative Example 1, and (b), (c), and (d) are the surface morphologies of the PI fiber modified by polydopamine deposition, coated with MXene nanosheets, and jointly modified by MXene-Ag in Example 1 in sequence, and (e) and (f) are the surface morphologies of the PI fiber jointly modified by MXene-Ag in Examples 2 and 3 in sequence;

[0023] Figure 3 It is the scanning electron microscope photographs of the PTFE fibers in Comparative Example 1 and Examples 1 to 3. Figure 3 In it, (a) is the morphology of the PTFE fiber in Comparative Example 1, and (b), (c), and (d) are the surface morphologies of the PTFE fiber modified by polydopamine deposition, coated with MXene nanosheets, and jointly modified by MXene-Ag in Example 1 in sequence, and (e) and (f) are the surface morphologies of the PTFE fiber jointly modified by MXene-Ag in Examples 2 and 3 in sequence;

[0024] Figure 4 It is the bar chart of the wear rate and friction coefficient of the self-lubricating bearings in Comparative Example 1, Comparative Example 2, and Example 1;

[0025] Figure 5 It is the scanning electron microscope images of the worn surfaces of the self-lubricating bearings in Comparative Example 1, 2, and Example 1. Figure 5 In it, (a) and (a 1 ) are the scanning electron microscope images of the worn surface of the self-lubricating bearing in Comparative Example 1; (b) and (b 1 ) are the scanning electron microscope images of the worn surface of the self-lubricating bearing in Comparative Example 2; (c) and (c 1 ) are the scanning electron microscope images of the worn surface of the self-lubricating bearing in Example 1. Detailed Description of the Invention

[0026] The present invention provides an MXene-Ag combined modified PI / PTFE blended fabric, which includes a PI / PTFE blended fabric, a polydopamine transition layer compounded on the surface of the PI / PTFE blended fabric, and MXene thin nanosheets adsorbed on the surface of the PI / PTFE blended fabric through hydrogen bonding with the polydopamine transition layer; Ag nanoparticles are in-situ loaded on the surface of the MXene thin nanosheets.

[0027] The present invention endows the surface of the PI / PTFE blended fabric with increased surface roughness and active group content through the combined modification of MXene nanosheets and Ag nanoparticles, thereby effectively improving the interfacial bonding performance between the PI / PTFE blended fabric and the phenolic resin matrix; and the MXene nanosheets and Ag nanoparticles existing at the interface of the PI / PTFE blended fabric composite are transferred to the friction interface during the friction process and participate in the construction of the friction transfer film, realizing the further improvement of the tribological performance of the PI / PTFE blended fabric composite.

[0028] The present invention provides a preparation method of the MXene-Ag combined modified PI / PTFE blended fabric described in the above technical solution, which includes the following steps:

[0029] (1) Mix the PI / PTFE blended fabric, a Tris-HCl buffer solution of hydrochloric acid dopamine, a catalyst and an oxidant to carry out an oxidative self-polymerization reaction to obtain a polydopamine modified PI / PTFE blended fabric;

[0030] (2) Mix the polydopamine modified PI / PTFE blended fabric with an MXene thin nanosheet aqueous dispersion to obtain an MXene nanosheet modified PI / PTFE blended fabric;

[0031] (3) Mix the MXene nanosheet modified PI / PTFE blended fabric with an AgNO 3 aqueous solution to carry out an in-situ reduction reaction of Ag + to obtain the MXene-Ag combined modified PI / PTFE blended fabric.

[0032] In the present invention, unless otherwise specified, the raw materials involved are all commercially available products well-known to those skilled in the art.

[0033] In the present invention, a PI / PTFE blended fabric, a Tris-HCl buffer solution of dopamine hydrochloride, a catalyst, and an oxidant are mixed to carry out an oxidative self-polymerization reaction to obtain a polydopamine-modified PI / PTFE blended fabric. In the present invention, the PI / PTFE blended fabric preferably has polytetrafluoroethylene fibers as the warp yarn and polyimide fibers as the weft yarn. In the present invention, the concentration of dopamine hydrochloride in the Tris-HCl buffer solution of dopamine hydrochloride is preferably 1 to 3 mg / mL, more preferably 2 mg / mL; the pH value of the Tris-HCl buffer solution of dopamine hydrochloride is preferably 8 to 10, more preferably 8.5; the concentration of tris(hydroxymethyl)aminomethane in the Tris-HCl buffer solution of dopamine hydrochloride is preferably 20 to 50 mmol / L, more preferably 20 to 30 mmol / L. The present invention has no special requirements for the dosage of the Tris-HCl buffer solution of dopamine hydrochloride, and it is only necessary to completely immerse the PI / PTFE blended fabric. In the examples of the present invention, the size of the PI / PTFE blended fabric is 3.5 cm × 10.5 cm, and it is immersed in 80 to 200 mL of the Tris-HCl buffer solution of dopamine hydrochloride. In the present invention, the catalyst is preferably CuSO 4 , and in the examples of the present invention, the CuSO 4 is specifically added in the form of CuSO 4 ·5H 2 O; the oxidant is preferably H 2 O 2 , and in the examples of the present invention, the H 2 O 2 is specifically added in the form of a 30 wt% hydrogen peroxide saturated aqueous solution; the introduction of CuSO 4 and H 2 O 2 generates a large amount of reactive oxygen free radicals in the solution, and at the same time, Cu + binds to polydopamine through chelation in the solution, which can greatly accelerate the oxidative polymerization reaction of dopamine in the solution. In the present invention, the dosage ratio of the catalyst to the Tris-HCl buffer solution of dopamine hydrochloride is preferably 4 to 6 mmol:1 L, more preferably 5 mmol:1 L; the molar ratio of the oxidant to the catalyst is preferably 4 to 6:1, more preferably 4 to 5:1. In the examples of the present invention, based on H 2 O 2The amount is used as the amount of the oxidant. In the present invention, the method of mixing the PI / PTFE blended fabric, the Tris-HCl buffer solution of dopamine hydrochloride, the catalyst and the oxidant is preferably as follows: the PI / PTFE blended fabric is immersed in the Tris-HCl buffer solution of dopamine hydrochloride, and then the catalyst and the oxidant are sequentially added to the obtained mixed system. In the present invention, the oxidative self-polymerization reaction can be carried out at room temperature. The time of the oxidative self-polymerization reaction is preferably 0.5 to 2 h, more preferably 1 h. The oxidative self-polymerization is preferably carried out under stirring conditions. After the oxidative self-polymerization is completed, the present invention preferably takes out the obtained blended fabric, rinses and dries it in sequence to obtain a polydopamine-modified PI / PTFE blended fabric.

[0034] In the present invention, dopamine hydrochloride oxidatively self-polymerizes to form polydopamine under the action of an oxidant and a catalyst, and is deposited on the surface of the PI / PTFE blended fabric, endowing the surface of the PI / PTFE blended fabric with rich hydroxyl functional groups. These groups contribute to the subsequent hydrogen bond interaction with the hydroxyl groups on the surface of the MXene nanosheets, and adsorb the MXene nanosheets on the surface of the blended fabric.

[0035] After obtaining the polydopamine-modified PI / PTFE blended fabric, the present invention mixes the polydopamine-modified PI / PTFE blended fabric with the aqueous dispersion of MXene thin nanosheets to obtain an MXene nanosheet-modified PI / PTFE blended fabric. In the present invention, the concentration of the MXene thin nanosheets in the aqueous dispersion of MXene thin nanosheets is preferably 1 to 3 mg / mL, more preferably 2 to 3 mg / mL. In the present invention, the number of layers of the MXene thin nanosheets is preferably ≤5 layers; the present invention has no special requirements on the source of the MXene thin nanosheets, and they can be obtained by using commercially available products or by preparing them by the preparation methods well-known to those skilled in the art; in the examples of the present invention, the MXene thin nanosheets are preferably obtained by ultrasonic exfoliation after etching Ti 3 AlC 2 with hydrofluoric acid. The specific preparation method is as follows: lithium fluoride (LiF) is dissolved in hydrochloric acid solution to obtain hydrofluoric acid solution; Ti 3 AlC 2Powder is etched under stirring conditions, and the obtained product is successively filtered, washed, and dried to obtain an etched product; the etched product is ultrasonically exfoliated in ice water under an argon atmosphere, and the obtained exfoliated product is centrifuged to remove the precipitate, and the upper layer is a dispersion of thin-layer MXene nanosheets; the dispersion of thin-layer MXene nanosheets is freeze-dried to obtain MXene thin-layer nanosheets. In the present invention, the concentration of the hydrochloric acid solution is preferably 9 mol / L, and the dosage ratio of lithium fluoride to the hydrochloric acid solution is preferably (2-10) g:100 mL, more preferably (3-5) g:100 mL; the dosage ratio of the Ti 3 AlC 2 powder to the hydrofluoric acid solution is preferably (3-10) g:100 mL, more preferably (3-8) g:100 mL. In the present invention, the temperature of the etching is preferably 35 °C, the time is preferably 24-48 h, more preferably 36-48 h; the time of the ultrasonic exfoliation is preferably 1-4 h, more preferably 2-4 h; the rotation speed of the centrifugation is preferably 3500 r / min. The present invention has no special requirements for the freeze-drying method, and the freeze-drying method well-known to those skilled in the art can be used.

[0036] The present invention has no special requirements for the dosage of the MXene thin-layer nanosheet aqueous dispersion, and it is only necessary to completely immerse the polydopamine-modified PI / PTFE blended fabric. In the examples of the present invention, the size of the polydopamine-modified PI / PTFE blended fabric is 3.5 cm × 10.5 cm, and it is immersed in 80-200 mL of the MXene thin-layer nanosheet aqueous dispersion. In the present invention, the mixing of the polydopamine-modified PI / PTFE blended fabric and the MXene thin-layer nanosheet aqueous dispersion can be carried out at room temperature, the mixing time is preferably 1-2 h, more preferably 1-1.5 h, and the mixing is carried out under stirring conditions. During the mixing process, by virtue of the hydrogen bond interaction between the surface groups of the MXene thin-layer nanosheets and the surface groups of the polydopamine, the MXene nanosheets are coated on the surface of the PI / PTFE blended fabric. After mixing is completed, the present invention preferably takes out the obtained blended fabric, successively washes and vacuum-dries it to obtain the MXene nanosheet-modified PI / PTFE blended fabric.

[0037] After obtaining the MXene nanosheet-modified PI / PTFE blended fabric, the present invention mixes the MXene nanosheet-modified PI / PTFE blended fabric with an AgNO 3 aqueous solution to carry out an Ag + in-situ reduction reaction to obtain the MXene-Ag co-modified PI / PTFE blended fabric. In the present invention, AgNO 3 in the AgNO 3The concentration is preferably 1 to 4 mg / mL, specifically it can be 1 mg / mL, 2 mg / mL, 3 mg / mL, 4 mg / mL; the present invention has no special requirements for the dosage of the 3 aqueous solution, and it is only necessary to completely immerse the MXene nanosheet modified PI / PTFE blended fabric. In the examples of the present invention, the size of the MXene nanosheet modified PI / PTFE blended fabric is 3.5 cm × 10.5 cm, and it is immersed in 80 to 200 mL of 3 aqueous solution. In the present invention, the + in-situ reduction reaction can be carried out at room temperature, and the time of the + in-situ reduction reaction is preferably 0.5 to 1 h, and the + in-situ reduction reaction is preferably carried out under stirring conditions. The present invention utilizes the reduction performance of MXene nanosheets to + in-situ reduce Ag to Ag nanoparticles and load them on the surface of the PI / PTFE blended fabric. After the + in-situ reduction reaction, the present invention preferably washes and vacuum-dries the obtained blended fibers in sequence to obtain the MXene-Ag jointly modified PI / PTFE blended fabric.

[0038] The present invention provides a phenolic resin-based composite material, including the MXene-Ag jointly modified PI / PTFE blended fabric described in the above technical solution or the MXene-Ag jointly modified PI / PTFE blended fabric prepared by the preparation method described in the above technical solution, and phenolic resin attached to the surface and inside of the MXene-Ag jointly modified PI / PTFE blended fabric; the mass percentage content of phenolic resin in the phenolic resin-based composite material is 15 to 40%, preferably 25 to 30%, and more preferably 27 to 30%. The phenolic resin-based composite material provided by the present invention has good interfacial bonding performance and significantly improved friction and wear performance.

[0039] The present invention provides a preparation method of the phenolic resin-based composite material described in the above technical solution, including the following steps:

[0040] Immerse the MXene-Ag jointly modified PI / PTFE blended fabric in a phenolic resin dispersion liquid and then dry it to obtain the phenolic resin-based composite material.

[0041] In the present invention, the phenolic resin dispersion is specifically a solution 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 is preferably (0.5-1):(0.5-1):(0.5-1); the dosage ratio of phenolic resin to the organic solvent is preferably 1 g:(5-10) mL. The present invention has no special requirements for the dosage of the phenolic resin dispersion, and it is only necessary to fully impregnate the MXene-Ag combined modified PI / PTFE blended fabric. In the examples of the present invention, the size of the MXene-Ag combined modified PI / PTFE blended fabric is 3.5 cm × 10.5 cm, and the volume of the phenolic resin dispersion is 80-200 mL. In the present invention, the drying temperature is preferably 40-80 °C, more preferably 50-70 °C, and the time is preferably 5-30 min, more preferably 10-20 min. In the present invention, after drying, it is also preferably to weigh the dried composite material and calculate the mass percentage of phenolic resin in the dried composite material; when the mass percentage of phenolic resin in the dried composite material is not within the above-defined range, the steps of impregnation and drying are repeated until the mass percentage of phenolic resin in the dried composite material reaches the above-defined range.

[0042] The present invention provides the application of the phenolic resin-based composite material described in the above technical solution or the phenolic resin-based composite material prepared by the preparation method described in the above technical solution in the field of solid lubrication.

[0043] The present invention also provides a self-lubricating bearing material, which includes a support material and a phenolic resin-based composite material bonded to the support material. The phenolic resin-based composite material is the phenolic resin-based composite material described in the above technical solution or the phenolic resin-based composite material prepared by the preparation method described in the above technical solution. In the present invention, the material of the support material is preferably a metal; the metal preferably includes 9Cr18, GCr15 or 17-4PH, and more preferably 9Cr18 or 17-4PH. The present invention preferably uses a phenolic resin adhesive to paste the phenolic resin-based composite material on the surface of the support material, and then carries out a curing reaction under certain temperature and pressure conditions to obtain the self-lubricating bearing material. The present invention does not specifically limit the amount of the phenolic resin adhesive, as long as it can bond the support material and the phenolic resin-based composite material together. In the present invention, the pressure of the curing is preferably 0.5 to 3 MPa, more preferably 1 to 2 MPa; the curing includes a first curing and a second curing carried out in sequence. The temperature of the first curing is preferably 150 °C, and the heat preservation time is preferably 30 to 60 min, more preferably 40 to 50 min. The time required to rise from room temperature to the temperature of the first curing is preferably 30 to 60 min, more preferably 50 min; the temperature of the second curing is preferably 180 °C, and the heat preservation time is preferably 100 to 140 min, more preferably 100 to 120 min. The time required to rise from the temperature of the first curing to the temperature of the second curing is preferably 30 min. The present invention divides the curing into the above two temperature stages to carry out preliminary curing and deep curing in sequence, which can avoid too fast heating rate leading to too fast curing reaction and causing a large number of pores inside the resin.

[0044] The following examples are used to illustrate in detail the MXene-Ag combined modified PI / PTFE blended fabric, phenolic resin-based composite material, preparation method and application provided by the present invention, but they should not be construed as limiting the protection scope of the present invention.

[0045] Example 1

[0046] Immerse the PI / PTFE blended fabric (3.5 cm × 10.5 cm) in 100 mL of Tris-HCl buffer solution of hydrochloric acid dopamine (the pH value of the buffer solution is 8.5, the concentration of tris(hydroxymethyl)aminomethane is 20 mmol / L, and the concentration of hydrochloric acid dopamine is 2 mg / mL); sequentially add 0.125 g of CuSO 4 ·5H 2 O and 30 wt% hydrogen peroxide saturated aqueous solution (containing 0.07 g of H 2 O 2 ) into the solution. After stirring and reacting at room temperature for 1 h, take out the PI / PTFE blended fabric, rinse it and dry it to obtain the poly-dopamine modified PI / PTFE blended fabric.

[0047] Preparation of MXene thin-layer nanosheets: Dissolve 1 g of lithium fluoride (LiF) in 30 mL of hydrochloric acid solution (hydrochloric acid solution concentration: 9 mol / L) to obtain a hydrofluoric acid solution; add 1 g of Ti 3 AlC 2 powder, and perform etching under stirring conditions. The etching temperature is 35 °C and the time is 48 h. Filter, wash, and dry the obtained product in sequence to obtain an etched product; ultrasonically exfoliate the etched product in ice water with an argon atmosphere introduced, and the exfoliation time is 1 h. Centrifuge the obtained exfoliated product (centrifugation speed: 3500 r / min) to remove the precipitate, and the upper layer is a dispersion of thin-layer MXene nanosheets; freeze-dry the dispersion of thin-layer MXene nanosheets to obtain MXene thin-layer nanosheets (number of layers ≤ 5 layers).

[0048] Immerse the poly-dopamine-modified PI / PTFE blended fabric in 100 mL of an aqueous dispersion of MXene thin-layer nanosheets (2 mg / mL), stir and react at room temperature for 1 h, and then wash and vacuum-dry to obtain a PI / PTFE blended fabric modified with MXene nanosheets.

[0049] Immerse the PI / PTFE blended fabric modified with MXene nanosheets in 100 mL of an aqueous solution of silver nitrate (1 mg / mL), stir and react at room temperature for 1 h. Utilize the reduction property of MXene nanosheets to + in-situ reduce it to Ag nanoparticles, and the Ag nanoparticles are in-situ loaded on the surface of the PI / PTFE blended fabric. Then wash and vacuum-dry to obtain a PI / PTFE blended fabric jointly modified with MXene-Ag.

[0050] Immerse the PI / PTFE blended fabric jointly modified with MXene-Ag repeatedly in a phenolic resin solution and dry it (each drying temperature is controlled at 50 °C and the time is 15 min) to obtain a PI / PTFE fabric-reinforced resin composite material jointly modified with MXene-Ag (i.e., a phenolic resin-based composite material); the mass fraction of phenolic resin in the PI / PTFE fabric-reinforced resin composite material jointly modified with MXene-Ag is 25%.

[0051] Use a phenolic resin adhesive to paste the obtained fabric-reinforced resin composite material on the surface of a metal substrate (9Cr18), and under a pressure condition of 2 MPa, raise the temperature from room temperature to 150 °C in 50 min, keep it at 150 °C for 30 min, raise the temperature from 150 °C to 180 °C in 30 min, and keep it at 180 °C for 140 min to obtain a self-lubricating bearing material.

[0052] Example 2

[0053] Immerse the PI / PTFE blended fabric (3.5 cm × 10.5 cm) into 100 mL of Tris-HCl buffer solution of dopamine hydrochloride (the pH value of the buffer solution is 8.5, the concentration of tris(hydroxymethyl)aminomethane is 20 mmol / L, and the concentration of dopamine hydrochloride is 2 mg / mL); sequentially add 0.125 g of CuSO 4 ·5H 2 O and 30 wt% saturated aqueous hydrogen peroxide solution (containing 0.07 g of H 2 O 2 ) to the solution, stir and react at room temperature for 1 h, then take out the PI / PTFE blended fabric, rinse and dry it to obtain the poly-dopamine modified PI / PTFE blended fabric.

[0054] Immerse the poly-dopamine modified PI / PTFE blended fabric into 100 mL of the aqueous dispersion of MXene thin nanosheets (the MXene preparation method is the same as that in Example 1) (2 mg / mL), stir and react at room temperature for 1 h, and then obtain the MXene nanosheet modified PI / PTFE blended fabric after washing and vacuum drying.

[0055] Immerse the MXene nanosheet modified PI / PTFE blended fabric into 100 mL of aqueous silver nitrate (2 mg / mL) solution, stir and react at room temperature for 1 h, and utilize the reduction performance of the MXene nanosheets to in-situ reduce Ag + to Ag nanoparticles, and the Ag nanoparticles are in-situ loaded on the surface of the PI / PTFE blended fabric, and then obtain the MXene-Ag jointly modified PI / PTFE blended fabric after washing and vacuum drying.

[0056] Immerse the MXene-Ag jointly modified PI / PTFE blended fabric repeatedly into and dry it in the phenolic resin solution (the drying temperature is controlled at 50 °C each time and the time is 15 min) to obtain the MXene-Ag jointly modified PI / PTFE fabric reinforced resin composite material (i.e., the phenolic resin-based composite material); the mass fraction of the phenolic resin in the MXene-Ag jointly modified PI / PTFE fabric reinforced resin composite material is 27%.

[0057] Use the phenolic resin adhesive to paste the obtained fabric reinforced resin composite material on the surface of the metal substrate (9Cr18), and under the condition of 2 MPa pressure, raise the temperature from room temperature to 150 °C in 50 min, keep it at 150 °C for 30 min, raise the temperature from 150 °C to 180 °C in 30 min, and keep it at 180 °C for 140 min to obtain the self-lubricating bearing material.

[0058] Example 3

[0059] Immerse the PI / PTFE blended fabric (3.5 cm × 10.5 cm) into 100 mL of Tris-HCl buffer solution of dopamine (the pH value of the buffer solution is 8.5, the concentration of tris(hydroxymethyl)aminomethane is 20 mmol / L, and the concentration of dopamine hydrochloride is 2 mg / mL); sequentially add 0.125 g of CuSO 4 ·5H 2 O and 30 wt% saturated aqueous hydrogen peroxide solution (containing 0.07 g of H 2 O 2 ) into the solution, stir and react at room temperature for 1 h, then take out the PI / PTFE blended fabric, rinse it, and dry it to obtain the poly-dopamine modified PI / PTFE blended fabric.

[0060] Immerse the poly-dopamine modified PI / PTFE blended fabric into 100 mL of aqueous dispersion of MXene nanosheets (the preparation method of MXene is the same as that in Example 1) (2 mg / mL), stir and react at room temperature for 1 h, and then obtain the MXene nanosheet modified PI / PTFE blended fabric after washing and vacuum drying.

[0061] Immerse the MXene nanosheet modified PI / PTFE blended fabric into 100 mL of aqueous solution of silver nitrate (4 mg / mL), stir and react at room temperature for 1 h, and utilize the reduction property of MXene nanosheets to in-situ reduce Ag + to Ag nanoparticles, and the Ag nanoparticles are in-situ loaded on the surface of the PI / PTFE blended fabric, and then obtain the MXene-Ag jointly modified PI / PTFE blended fabric after washing and vacuum drying.

[0062] Immerse the MXene-Ag jointly modified PI / PTFE blended fabric into the phenolic resin solution repeatedly and dry it (the drying temperature is controlled at 50 °C each time, and the time is 15 min) to obtain the MXene-Ag jointly modified PI / PTFE fabric reinforced resin composite material (i.e., phenolic resin-based composite material); the mass fraction of phenolic resin in the MXene-Ag jointly modified PI / PTFE fabric reinforced resin composite material is 30%.

[0063] Use the phenolic resin adhesive to paste the obtained fabric reinforced resin composite material on the surface of the metal substrate (17-4PH), and under the condition of 2 MPa pressure, raise the temperature from room temperature to 150 °C in 50 min, keep it at 150 °C for 30 min, raise the temperature from 150 °C to 180 °C in 30 min, and keep it at 180 °C for 140 min to obtain the self-lubricating bearing material.

[0064] Example 4

[0065] Immerse the PI / PTFE blended fabric (3.5 cm × 10.5 cm) into 100 mL of Tris-HCl buffer solution of dopamine (the pH value of the buffer solution is 8.5, the concentration of tris(hydroxymethyl)aminomethane is 20 mmol / L, and the concentration of dopamine hydrochloride is 2 mg / mL); sequentially add 0.125 g of CuSO 4 ·5H 2 O and 30 wt% saturated aqueous hydrogen peroxide solution (containing 0.07 g of H 2 O 2 ). After stirring and reacting at room temperature for 1 h, take out the PI / PTFE blended fabric, rinse it, and dry it to obtain the poly-dopamine modified PI / PTFE blended fabric.

[0066] Immerse the poly-dopamine modified PI / PTFE blended fabric into 100 mL of aqueous dispersion of MXene thin nanosheets (the MXene preparation method is the same as that in Example 1) (3 mg / mL), stir and react at room temperature for 1 h, and then obtain the MXene nanosheet modified PI / PTFE blended fabric after washing and vacuum drying.

[0067] Immerse the MXene nanosheet modified PI / PTFE blended fabric into 100 mL of aqueous solution of silver nitrate (2 mg / mL), stir and react at room temperature for 1 h. Utilize the reduction performance of MXene nanosheets to in-situ reduce Ag + to Ag nanoparticles. The Ag nanoparticles are in-situ loaded on the surface of the PI / PTFE blended fabric, and then obtain the MXene-Ag combined modified PI / PTFE blended fabric after washing and vacuum drying.

[0068] Repeatedly immerse and dry the MXene-Ag combined modified PI / PTFE blended fabric in the phenolic resin solution (the drying temperature is controlled at 50 °C each time, and the time is 15 min) to obtain the MXene-Ag combined modified PI / PTFE fabric reinforced resin composite material (i.e., phenolic resin-based composite material); the mass fraction of phenolic resin in the MXene-Ag combined modified PI / PTFE fabric reinforced resin composite material is 25%.

[0069] Use phenolic resin adhesive to paste the obtained fabric reinforced resin composite material on the surface of the metal substrate (17-4PH), and under the condition of 2 MPa pressure, raise the temperature from room temperature to 150 °C in 50 min, keep it at 150 °C for 30 min, raise the temperature from 150 °C to 180 °C in 30 min, and keep it at 180 °C for 140 min to obtain the self-lubricating bearing material.

[0070] Comparative Example 1

[0071] Prepare the PI / PTFE blended fabric reinforced phenolic resin matrix composite material according to the preparation method of Example 1, with the difference that: no surface modification is carried out on the PI / PTFE blended fabric.

[0072] Comparative Example 2

[0073] Prepare the PI / PTFE blended fabric reinforced phenolic resin matrix composite material according to the preparation method of Example 1, with the difference that: only polydopamine polymerization deposition and MXene nanosheet coating are carried out on the surface of the PI / PTFE blended fabric, and silver nanoparticles are not further deposited.

[0074] Characterize the morphology of the MXene nanosheets prepared in Example 1 to obtain scanning electron microscope photos, as Figure 1 shown, Figure 1 in, the left figure is the product after etching the Ti 3 AlC 2 powder with hydrofluoric acid solution, which is a multi-layer MXene material, and the right figure is the MXene thin-layer nanosheet material obtained after etching and exfoliating the Ti 3 AlC 2 powder.

[0075] Perform scanning electron microscopy observations on the surface-modified PI / PTFE fabrics of Examples 1 to 3 and the PI / PTFE blended fabric of Comparative Example 1 to obtain scanning electron microscope photos of the PI and PTFE fiber surfaces before and after modification, as Figure 2 and Figure 3 shown, Figure 2 are the scanning electron microscope photos of the PI fibers in Comparative Example 1 and Examples 1 to 3. Among them, (a) is the morphology of the PI fibers in Comparative Example 1, from which it can be seen that the surface of the unmodified PI fibers is smooth; (b), (c), and (d) are the surface morphologies of the PI fibers modified by polydopamine deposition, MXene nanosheet coating, and MXene-Ag combined modification in Example 1 in sequence, and it can be clearly seen that the surface roughness of the PI fibers gradually increases; (e) and (f) are the surface morphologies of the PI fibers modified by MXene-Ag combined modification in Example 2 and Example 3 in sequence, and it can be seen that as the concentration of the silver nitrate reaction solution in Examples 1 to 3 gradually increases, the Ag nanoparticles deposited on the surface of the PI fibers gradually increase, and the surface roughness of the PI fibers is also getting higher and higher.

[0076] Figure 3 are the scanning electron microscope photos of the PTFE fibers in Comparative Example 1 and Examples 1 to 3, Figure 3In (a), it is the PTFE fiber morphology in Comparative Example 1. It can be seen that the surface of the unmodified PTFE fiber is also relatively smooth. In (b), (c), and (d) are the surface morphologies of the PTFE fibers modified by polydopamine deposition, coated with MXene nanosheets, and jointly modified with MXene-Ag in Example 1 in sequence. It can be clearly seen that the surface roughness of the PTFE fiber gradually increases. In (e) and (f) are the surface morphologies of the PTFE fibers jointly modified with MXene-Ag in Example 2 and Example 3 in sequence. It can be seen that as the concentration of the silver nitrate reaction solution gradually increases in Examples 1 to 3, the Ag nanoparticles deposited on the surface of the PTFE fiber gradually increase, and the surface roughness of the PTFE fiber is also getting higher and higher.

[0077] Using 45# steel with a diameter of 2 mm as the friction pair, the friction and wear properties of the self-lubricating bearings prepared from the PI / PTFE blended fabric reinforced resin composites in Examples 1 to 4 and the PI / PTFE blended fabric reinforced phenolic resin-based composites in Comparative Examples 1 to 2 were detected by a Xuanwu No. 3 friction and wear testing machine at room temperature, with an applied load of 75 MPa (240 N), a friction rotation speed of 0.26 m / s, a friction time of 120 min, and a radius of 12.5 mm. The results are listed in Table 1. Among them, the friction coefficient is automatically output by processing the data collected by the connected computer; the wear depth of the wear-resistant material is measured by a digital display height gauge, and then the wear volume of the fabric composite material is calculated. The wear rate of the wear-resistant material is calculated according to Formula 1:

[0078] K = ΔV / P˙L Formula 1;

[0079] Where, K is the wear rate (m 3 (N˙m) -1 );ΔV is the wear volume (m 3 );P is the applied load (N); L is the sliding distance (m); where L = v˙t (v is the friction rotation speed, t is the friction time).

[0080] Table 1 Friction and wear properties of the self-lubricating bearings in Examples 1 to 4 and Comparative Examples 1 to 2

[0081]

[0082] Figure 4 Bar charts of the wear rate and friction coefficient of the self-lubricating bearings in Comparative Example 1, Comparative Example 2, and Example 1 are given.

[0083] Combined with Table 1 and Figure 4It can be seen that: compared with Comparative Example 1, the wear rate and friction coefficient of the self-lubricating bearing in Example 1 are reduced by 40% and 23% respectively. It shows that the MXene-Ag combined modification of PI / PTFE blended fabric effectively improves the friction and wear performance of the obtained self-lubricating bearing.

[0084] After the friction tests of the self-lubricating bearings of Comparative Examples 1 and 2 and Example 1 were carried out according to the above method, the surface topography of the worn surface was detected, and scanning electron microscope photos were obtained, as Figure 5 shown. Figure 5 In, (a) and (a 1 ) are the scanning electron microscope images of the worn surface of the self-lubricating bearing of Comparative Example 1; (b) and (b 1 ) are the scanning electron microscope images of the worn surface of the self-lubricating bearing of Comparative Example 2; (c) and (c 1 ) are the scanning electron microscope images of the worn surface of the self-lubricating bearing of Example 1, Figure 5 In (a 1 ), (b 1 ), (c 1 ) are the enlarged views of (a), (b), and (c) respectively. It can be Figure 5 seen that the worn 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 damaged; while the worn surface of Example 1 is relatively smooth, further indicating that the MXene-Ag combined modified PI / PTFE blended fabric phenolic resin-based composite material provided by the present invention has high tribological performance.

[0085] It can be seen from the above examples that the present invention uses MXene-Ag combined modification of PI / PTFE blended fabric to improve the interfacial bonding performance between the functionalized gasket fabric and the resin matrix, and promotes the stress transfer of the gasket fabric reinforced resin composite material when subjected to external forces; at the same time, MXene nanosheets and Ag nanoparticles are transferred to the friction interface during the friction process and participate in the construction process of the high-quality friction transfer film, further realizing the improvement of the tribological performance of the MXene-Ag combined modified PI / PTFE blended fabric composite material.

[0086] The above is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. An MXene-Ag combined modified PI / PTFE blended fabric, comprising a PI / PTFE blended fabric, a polydopamine transition layer compounded on the surface of the PI / PTFE blended fabric, and MXene thin nanosheets adsorbed on the surface of the PI / PTFE blended fabric through hydrogen bonding with the polydopamine transition layer; Ag nanoparticles are in-situ loaded on the surface of the MXene thin nanosheets.

2. The preparation method of the MXene-Ag combined modified PI / PTFE blended fabric according to claim 1, comprising the following steps: (1) Mix a PI / PTFE blended fabric, a Tris-HCl buffer solution of hydrochloric acid dopamine, a catalyst and an oxidant to carry out an oxidative self-polymerization reaction to obtain a polydopamine modified PI / PTFE blended fabric; (2) Mix the polydopamine modified PI / PTFE blended fabric with an MXene thin nanosheet aqueous dispersion to obtain an MXene nanosheet modified PI / PTFE blended fabric; (3) Mix the modified PI / PTFE blended fabric with the MXene nanosheets and AgNO 3 aqueous solution, and carry out an in-situ + reduction reaction of Ag to obtain the MXene-Ag co-modified PI / PTFE blended fabric.

3. According to the preparation method described in claim 2, characterized in that, In the step (1), the concentration of dopamine hydrochloride in the Tris-HCl buffer solution of dopamine hydrochloride is 1 to 3 mg / mL; the catalyst is CuSO 4 , and the oxidant is H 2 O 2 ; the dosage ratio of the catalyst to the Tris-HCl buffer solution of dopamine hydrochloride is 4 to 6 mmol: 1 L; the molar ratio of the oxidant to the catalyst is 4 to 6:

1.

4. According to the preparation method described in claim 2 or 3, characterized in that, the time of the oxidative self-polymerization reaction in the step (1) is 0.5 - 2 h.

5. According to the preparation method described in claim 2, characterized in that, in the step (2), the concentration of MXene thin nanosheets in the MXene thin nanosheet aqueous dispersion is 1 - 3 mg / mL, the mixing time is 1 - 2 h, and the mixing is carried out under stirring conditions.

6. According to the preparation method described in claim 2, characterized in that, In the step (3), AgNO 3 In the AgNO 3 in the aqueous solution has a concentration of 1 to 4 mg / mL. The time for the + in-situ reduction reaction of Ag is 0.5 to 1 h. The + in-situ reduction reaction of Ag is carried out under stirring conditions.

7. A phenolic resin-based composite material, characterized in that, comprising the MXene-Ag combined modified PI / PTFE blended fabric described in claim 1 or the MXene-Ag combined modified PI / PTFE blended fabric prepared by the preparation method described in any one of claims 2 - 6, and phenolic resin attached to the surface and inside of the MXene-Ag combined modified PI / PTFE blended fabric; the mass percentage content of phenolic resin in the phenolic resin-based composite material is 15 - 40%.

8. The preparation method of the phenolic resin-based composite material according to claim 7, characterized in that, comprising the following steps: Immerse the MXene-Ag combined modified PI / PTFE blended fabric in a phenolic resin dispersion and then dry it to obtain the phenolic resin-based composite material.

9. The application of the phenolic resin-based composite material described in claim 7 or the phenolic resin-based composite material prepared by the preparation method described in claim 8 in the field of solid lubrication.

10. A self-lubricating bearing material, characterized in that, comprising a support material and a phenolic resin-based composite material bonded to the support material, and the phenolic resin-based composite material is the phenolic resin-based composite material described in claim 7 or the phenolic resin-based composite material prepared by the preparation method described in claim 8.

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