Antifriction and wear-resistant polyamide-imide composite material as well as preparation method and application thereof

Abstract

The invention discloses an antifriction wear-resistant polyamide-imide composite material as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials. The antifriction and wear-resistant polyamide-imide composite material is prepared from the following raw material components in parts by mass: 100 parts of basic slurry, 0.1 to 20 parts of functional filler, 0 to 50 parts of diluent, 0.1 to 1 part of defoaming agent and 0.1 to 1 part of dispersing agent, wherein the basic slurry is a water-based polyamide-imide emulsion; the functional filler is a biomass carbon composite molybdenum disulfide material treated by a siloxane coupling agent, and the biomass carbon is derived from typha orientalis derived carbon fibers. The composite material has the advantages of being low in friction coefficient and abrasion, wide in raw material source, environmentally friendly and high in dispersion stability; the preparation method is convenient in process and can meet the requirements of planned production; as an antifriction and wear-resistant material, the material has a wide application prospect in mechanical engineering materials.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a friction-reducing and wear-resistant polyamide-imide composite material and a preparation method and application thereof. Background Art

[0002] Polymer coating materials have good wear resistance and corrosion resistance. These materials are usually used in mechanical equipment, ships and buildings that need to withstand high temperature or chemical erosion. In general industry, polyamide-imide coatings can be used for bearings and wear-resistant parts, as well as parts that require high strength and hardness. However, the friction coefficient and wear rate of pure polyamide-imide coatings are high. By adjusting the composition and surface state of the polymer coating, its friction coefficient and wear rate can be effectively controlled and optimized.

[0003] Molybdenum disulfide (MoS 2 ) and carbon-based materials have significant effects in the field of anti-friction lubrication. Both can form a lubricating film at the interface, significantly reducing the friction coefficient. 2 After introducing carbon materials into the material, MoS 2 The surface morphology of the composite material can be improved to form a more uniform and continuous friction film, which helps to reduce friction and wear and increase the service life of the material. At the same time, the corrosion resistance of the carbon material can improve the overall corrosion resistance of the composite material, which is particularly important for the application of the material in harsh environments.

[0004] At present, the carbon materials used above are mainly derived from high-purity graphite and carbon nanotubes purchased from the laboratory. Their raw materials are often derived from non-renewable fossil fuels, such as methane and ethylene, and the production process requirements and costs are relatively high. In contrast, biomass carbon comes from biomass waste and is a renewable resource with certain advantages in terms of cost and environmental protection. With the development of technology, the performance of biomass carbon is constantly improving, and it has the potential to replace traditional carbon materials in more fields.

[0005] For example, the Chinese invention patent with publication number CN107298442A discloses a biomass carbon / molybdenum disulfide nanocomposite material and a preparation method thereof, which uses corn stalks, prepares biomass carbon by hydrothermal method and calcination, and then grows petal-shaped molybdenum disulfide nanomaterials on porous biomass carbon by one-step hydrothermal method. However, compared with traditional carbon materials, when general biomass carbon materials are used for polyamide-imide, the technical problem of poor dispersibility of composite materials in polyamide-imide emulsions is prone to occur. General biomass carbon particles are prone to agglomeration under high specific surface area, and the agglomerated particles form larger aggregates, which increases the difficulty of dispersion in the emulsion, and the Brownian motion effect of larger particles is weakened, and sedimentation is more likely to occur, which aggravates the difficulty of dispersion, thereby causing biomass carbon / molybdenum disulfide to be difficult to obtain the expected application effect in polyamide-imide, and its intuitive performance is poor lubrication performance, and the friction coefficient and wear of the composite material are high.

[0006] Therefore, a friction-reducing and wear-resistant polyamide-imide composite material and a preparation method thereof are provided to give full play to the advantages of biomass carbon materials, solve the above-mentioned defects of the prior art, and improve the high friction coefficient and wear problems of polyamide-imide materials in applications, which has positive significance for expanding the application of polyamide-imide coatings. Summary of the invention

[0007] In view of the above-mentioned defects of the prior art, in the first aspect of the present invention, a friction-reducing and wear-resistant polyamide-imide composite material with low friction coefficient and wear, wide raw material source, environmental friendliness and high dispersion stability is provided. The raw materials include the following components, in parts by mass: 100 parts of base slurry, 0.1-20 parts of functional filler, 0-50 parts of diluent, 0.1-1 part of defoaming agent, and 0.1-1 part of dispersant; wherein the base slurry is an aqueous polyamide-imide emulsion; the functional filler is a biomass carbon composite molybdenum disulfide material treated with a siloxane coupling agent, and the source of the biomass carbon is cattail-derived carbon fiber.

[0008] Cattail derived carbon fiber can be obtained by carbonizing clean cattail fluff fibers. Cattail fluff fibers have a high wax content. In actual operation, technicians in this field can wash them with suitable solvents such as water and ethanol (water washing can remove solid impurities such as sand and dust in the fibers, while ethanol can dissolve and remove some organic impurities such as grease and wax), dry them, and then carbonize them.

[0009] Preferably, the method for preparing cattail-derived carbon fibers comprises the following steps: removing impurities from the surface of cattail fluff fibers, drying and carbonizing at 700-900° C. for 2-4 h to obtain cattail-derived carbon fibers.

[0010] In actual operation, those skilled in the art can select the appropriate type of auxiliary agent according to actual needs and conditions.

[0011] Water, ethanol and isopropanol are suitable diluents for the polyamide-imide emulsion of the present invention, and can be selectively added and adjusted in amount according to parameters such as the viscosity of the base slurry used, so that the system has good processability. Water is outstanding in environmental protection, safety and cost-effectiveness, ethanol has advantages in solubility, volatility and antibacterial properties, and isopropanol is excellent in high solubility, low toxicity and good volatility.

[0012] Preferably, the diluent includes at least one of water, ethanol and isopropanol.

[0013] Among Silcona products, HLD-6, HLD-8ks, and HLD-11c are suitable dispersant selection types for the present invention. HLD-6 improves production efficiency with its wide applicability, HLD-8ks optimizes the dispersion effect of fillers through special formula design and reduces process complexity, and HLD-11c has environmental protection characteristics and is specially designed for water-based systems. It should be noted that dispersants are a conventional additive for coatings. Adding dispersants can improve the dispersibility of components to a certain extent, but in the application scenarios of the present invention, the agglomeration and weak dispersion of biomass carbon materials cannot be fully solved by increasing the amount of dispersant used.

[0014] Preferably, the dispersant includes at least one of HLD-6, HLD-8ks, and HLD-11c.

[0015] BYK series defoamers are high-performance additives produced by BYK in Germany, used to reduce foam problems in coating production. Among them, BYK-012, BYK-014, BYK-016 and other defoamers can reduce the surface tension of the mixed system in a short time, destroy the foam structure, and inhibit the generation of new foam.

[0016] Preferably, the defoaming agent includes at least one of BYK-012, BYK-014 and BYK-016.

[0017] In the second aspect of the present invention, a method for preparing the friction-reducing and wear-resistant polyamide-imide composite material of the first aspect of the present invention with convenient process is provided, comprising the following steps: (1) mixing cattail-derived carbon fibers, ammonium molybdate tetrahydrate, and thiourea in water to obtain a mixed solution; subjecting the mixed solution to a hydrothermal reaction, recovering a crude product after completion, and purifying the product to obtain a biomass carbon composite molybdenum disulfide material; (2) The biomass carbon composite molybdenum disulfide material is treated with a siloxane coupling agent and then added to an aqueous polyamide-imide emulsion, followed by adding a diluent, a dispersant, and a defoaming agent, mixing and dispersing to obtain a coating mixture; (3) The coating mixture is applied to the surface of the substrate, and then cured after being surface dried at room temperature. After completion, it is naturally annealed to obtain a friction-reducing and wear-resistant polyamide-imide composite material.

[0018] Preferably, in step (1), the amount of cattail derived carbon fiber is 0.4-1.0 g; the amount of ammonium molybdate tetrahydrate is 0.6-1.0 g; the amount of thiourea is 1.8-3.0 g; the mass ratio of ammonium molybdate tetrahydrate to thiourea is 1:3; and the amount of water is 40-60 mL.

[0019] Preferably, in step (1), the temperature of the hydrothermal reaction is 150-200°C, and the reaction time is 6-12 h.

[0020] The biomass carbon composite molybdenum disulfide material can be treated with a siloxane coupling agent by conventional methods in the art, and then added to an aqueous polyamide-imide emulsion. The siloxane coupling agent can act as a bridge between the inorganic filler and the organic polymer matrix, enhancing the chemical affinity between the two, reducing interface defects, etc. As presented in the embodiment of the present invention, 2 g of biomass carbon composite molybdenum disulfide material is taken, 1 mL of KH560 and 99 mL of ethanol are added, and then heated and stirred at 60 ° C for 3 h. Those skilled in the art may also use other methods to complete the treatment.

[0021] Preferably, in step (3), the curing temperature is 270-320° C. and the curing time is 3-8 h.

[0022] In the third aspect of the present invention, there is provided an application of the friction-reducing and wear-resistant polyamide-imide composite material of the first aspect of the present invention or the friction-reducing and wear-resistant polyamide-imide composite material prepared by the preparation method of the second aspect of the present invention, specifically, an application as a friction-reducing and wear-resistant material in mechanical engineering materials.

[0023] Based on the above technical scheme, the design concept of the present invention is to use cattail-derived carbon fibers as biomass carbon materials. The structure and other properties of biomass carbon are highly correlated with its biomass materials. Compared with ordinary biomass carbon materials, cattail-derived carbon fibers have specific micro / nano structures. Structurally, cattail fluff fibers have a multi-cavity structure, which is light and structurally stable. The trunk fiber bundle is composed of thin-walled cells and solid stone cells, and has high tensile strength and specific modulus. The branch fiber bundle is composed of a plurality of "semi-honeycomb-shaped" special-shaped thin-walled cells, and the internal diaphragm divides the special-shaped thin-walled cells into several open cavities. This structural feature makes the cattail fluff branch fiber bundle light, structurally stable, and has good oil adsorption and storage capacity. The above structure can provide stable physical support, protect the nanoparticles from agglomeration, and is conducive to improving their dispersibility in polyamide-imide emulsions. The present invention introduces cattail-derived carbon fibers composited with MoS 2Materials, using MoS 2 The inherent self-lubricating property combines the advantages of the stability and strong load-bearing capacity of the carbon material, giving full play to the advantages of cattail-derived carbon fiber and MoS 2 The synergistic effect between them effectively controls the friction coefficient and wear rate of the polymer coating.

[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects: The invention provides a friction-reducing and wear-resistant polyamide-imide composite material, which has the advantages of low friction coefficient and wear, wide raw material sources, environmental friendliness and high dispersion stability.

[0025] The invention provides a method for preparing a friction-reducing and wear-resistant polyamide-imide composite material. The method has a convenient process and can meet the needs of planned production.

[0026] The invention provides an application of a friction-reducing and wear-resistant polyamide-imide composite material, which has broad application prospects in mechanical engineering materials as a friction-reducing and wear-resistant material. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a physical picture of wild cattail and cattail fluff fiber; Figure 2 The scanning electron microscope image (a) and element distribution spectrum (b) of biomass carbon composite molybdenum disulfide material, the scale is 10 μm; Figure 3 The scanning electron microscope image and element distribution spectrum of the friction-reducing and wear-resistant polyamide-imide composite material prepared in Example 1; Figure 4 The friction coefficient curves of Examples 1-3 and the comparative group under dry friction and white oil conditions under a load of 10 N; Figure 5 The friction coefficient curves of Examples 1-3 and the comparative group under dry friction and white oil conditions at a load of 5 N; Figure 6 The white light images of the wear of Examples 1-3 under dry friction under a load of 10 N are shown. (a), (b), (c), and (d) are the wear images of the pure polyamide-imide coating and Examples 1-3 under dry friction, respectively. Figure 7 The white light images of the wear of Examples 1-3 under dry friction under a load of 5 N are shown. (a), (b), (c), and (d) are the wear images of the pure polyamide-imide coating and Examples 1-3 under dry friction, respectively. DETAILED DESCRIPTION

[0028] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0029] In the following embodiments: The actual pictures of wild cattail and cattail fluff fiber used are as follows: Figure 1 As shown; the preparation method of cattail derived carbon fiber is as follows: the cattail fluff fiber is washed with water and ethanol to remove surface impurities, and then heated to 800℃ for carbonization for 2 h after drying to obtain the cattail derived carbon fiber.

[0030] Example 1 The friction-reducing and wear-resistant polyamide-imide composite material of this embodiment is made by the following method: (1) 0.6 g of cattail-derived carbon fiber, 0.8 g of ammonium molybdate tetrahydrate and 2.4 g of thiourea were added to 50 mL of deionized water respectively, and magnetic stirring was performed for 30 min to mix them evenly to obtain a mixed solution; the mixed solution was then transferred to a reactor for hydrothermal reaction, and the oven heating and insulation conditions were set to 160 °C for 10 h. After the reaction was completed, the reactor was cooled naturally and the sample was taken out. After centrifugation, washing and vacuum drying, a biomass carbon composite molybdenum disulfide material was obtained; (2) Take 2 g of biomass carbon composite molybdenum disulfide material, add 1 mL of KH560 and 99 mL of ethanol, heat and stir at 60 ° C for 3 h, centrifuge, wash, and vacuum tube dry to complete the treatment; add 0.1 g of biomass carbon composite molybdenum disulfide material treated with siloxane coupling agent to 10 g of polyamide-imide emulsion, add 0.1 wt.% of polymer water-based defoamer and 0.1 wt.% of dispersant respectively, and mix the solution at 500 rpm to obtain a coating mixture; (3) The coating mixture was poured into a spray gun and sprayed onto the sandblasted Al sheet at a uniform speed. After being dried at room temperature, it was placed in an oven. The oven was heated and kept at 120 °C for 1 h, then increased to 270 °C for 1 h to complete the curing. It was then naturally annealed to form a film to obtain a friction-reducing and wear-resistant polyamide-imide composite material, named PAI-1% filler.

[0031] In this embodiment, the prepared biomass carbon composite molybdenum disulfide material is first characterized by scanning electron microscopy and element distribution analysis. The scanning electron microscopy image and element distribution spectrum of the biomass carbon composite molybdenum disulfide material are shown in FIG. Figure 2 As shown in the figure, the three elements S, Mo, and C are evenly distributed in the figure, indicating that MoS prepared by the hydrothermal method 2The particles were successfully grown and evenly dispersed in the cattail-derived carbon. The same method was used to further analyze the friction-reducing and wear-resistant polyamide-imide composite material. The characterization results are shown in Figure 2. Figure 3 As shown. Figure 3 It can be seen that the biomass carbon composite molybdenum disulfide material is uniformly dispersed in the polyamide-imide material, and no obvious agglomeration phenomenon is observed.

[0032] Example 2 This embodiment is basically the same as the embodiment 1, except that 0.2 g of biomass carbon composite molybdenum disulfide material treated with a siloxane coupling agent is added to 10 g of the polyamide-imide emulsion, and the obtained friction-reducing and wear-resistant polyamide-imide composite material is named PAI-2 filler %.

[0033] Example 3 This embodiment is basically the same as the embodiment 1, except that 0.3 g of the biomass carbon composite molybdenum disulfide material treated with a siloxane coupling agent is added to 10 g of the polyamide-imide emulsion, and the obtained friction-reducing and wear-resistant polyamide-imide composite material is named PAI-3% filler.

[0034] Example 4 This example studies the application effect of the friction-reducing and wear-resistant polyamide-imide composite material under dry friction and white oil working conditions.

[0035] Tribological performance test: The polyamide-imide composite material was subjected to tribological tests under dry friction and white oil conditions using a reciprocating friction and wear tester. The moving pair was a GCr15 bearing steel ball with a diameter of 6.35 mm, a load of 5 N and 10 N, a frequency of 2 Hz, and a working time of 20 min. After the friction experiment, a white light copolymerization three-dimensional topography was used to characterize the three-dimensional surface morphology of the wear marks and analyze the width and depth of the wear marks.

[0036] In the tribological performance test, pure polyamide-imide samples were used as the comparison group, and the preparation method was as follows: After stirring 10 g of aqueous polyamide-imide emulsion at 500 rpm for 5 min, 2 drops of polymer defoamer were added thereto. After stirring and defoaming, the material was poured into a spray gun and sprayed on the sandblasted Al sheet at a uniform speed. After natural surface drying, it was placed in an oven for curing. The oven temperature was increased to 280 °C, and after curing for 3 h, it was naturally annealed to room temperature. The Al sheet was taken out and cleaned with ethanol and the surface was blown dry with a nitrogen gun to obtain a polyamide-imide material, which was named pure PAI.

[0037] The friction coefficient test results of three anti-friction and wear-resistant polyamide-imide composites with different filler contents under dry friction and white oil conditions are shown in Figure 1. Figure 4As shown; correspondingly, the test results under 5 N load are as follows Figure 5 As shown. 2 It is a self-lubricating material. The introduction of biomass carbon material increases the hardness and overall stability of the material, so the friction coefficient of PAI-1% filler, PAI-2% filler, and PAI-3% filler has been significantly reduced. When the load is 10N, the average friction coefficients of the control group and Examples 1-3 are 0.5585, 0.4427, 0.3272, and 0.3597, respectively, and the friction coefficient of Example 2 is reduced by more than 40%. When the load is 5 N, the average friction coefficients of the control group and Examples 1-3 are 0.6654, 0.4924, 0.3649, and 0.4110, respectively, and the average friction coefficient of Example 2 is reduced by more than 45%. The different friction coefficients of Examples 1-3 are due to the different effects of different filler contents on the tribological properties of polyimide composites. At the same time, it can be seen that under white oil conditions, the friction coefficients of Examples 1-3 are all low, indicating that the prepared polyamide-imide composite material has the potential to be used under high-temperature white oil conditions.

[0038] The wear characteristics of three anti-friction and wear-resistant polyamide-imide composites with different filler contents under dry friction conditions under a load of 10 N are shown in Figure 2. Figure 6 As shown; correspondingly, the test results under 5 N load are as follows Figure 7 As shown in the figure, pure polyamide-imide has been worn through after the friction test under the above conditions. As can be seen from the two figures, after the introduction of the composite filler, the wear of Examples 1-3 was reduced and no wear-through phenomenon occurred.

[0039] In summary, the present invention introduces cattail derived carbon fiber composite MoS 2 Materials, using MoS 2 The inherent self-lubricating property combines the advantages of the stability and strong load-bearing capacity of the carbon material, giving full play to the advantages of cattail-derived carbon fiber and MoS 2 The synergistic effect between the two effectively controls the friction coefficient and wear rate of the polymer coating. The anti-friction and wear-resistant polyamide-imide composite material has broad application prospects in the fields of bearing outer coating and mechanical engineering materials.

[0040] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A friction-reducing and wear-resistant polyamide-imide composite material, characterized in that: The raw materials include the following components, in parts by mass: 100 parts of base slurry, 0.1-20 parts of functional filler, 0-50 parts of diluent, 0.1-1 parts of defoamer, and 0.1-1 parts of dispersant; wherein the base slurry is an aqueous polyamide-imide emulsion; the functional filler is a biomass carbon composite molybdenum disulfide material treated with a siloxane coupling agent, and the source of the biomass carbon is cattail-derived carbon fiber.

2. The friction-reducing and wear-resistant polyamide-imide composite material according to claim 1, characterized in that: The method for preparing cattail-derived carbon fibers comprises the following steps: removing impurities from the surface of cattail fluff fibers, drying and carbonizing at 700-900° C. for 2-4 h to obtain cattail-derived carbon fibers.

3. The friction-reducing and wear-resistant polyamide-imide composite material according to claim 1, characterized in that: The diluent includes at least one of water, ethanol and isopropanol.

4. The friction-reducing and wear-resistant polyamide-imide composite material according to claim 1, characterized in that: The dispersant includes at least one of HLD-6, HLD-8ks, and HLD-11c.

5. The friction-reducing and wear-resistant polyamide-imide composite material according to claim 1, characterized in that: The defoaming agent includes at least one of BYK-012, BYK-014 and BYK-016.

6. A method for preparing the friction-reducing and wear-resistant polyamide-imide composite material according to any one of claims 1 to 5, characterized in that: The steps include: (1) mixing cattail-derived carbon fibers, ammonium molybdate tetrahydrate, and thiourea in water to obtain a mixed solution; subjecting the mixed solution to a hydrothermal reaction, recovering a crude product after completion, and purifying the product to obtain a biomass carbon composite molybdenum disulfide material; (2) The biomass carbon composite molybdenum disulfide material is treated with a siloxane coupling agent and then added to an aqueous polyamide-imide emulsion, followed by adding a diluent, a dispersant, and a defoaming agent, mixing and dispersing to obtain a coating mixture; (3) The coating mixture is applied to the surface of the substrate, and then cured after being surface dried at room temperature. After completion, it is naturally annealed to obtain a friction-reducing and wear-resistant polyamide-imide composite material.

7. The method for preparing the friction-reducing and wear-resistant polyamide-imide composite material according to claim 6, characterized in that: In the step (1), the amount of cattail derived carbon fiber is 0.4-1.0 g; the amount of ammonium molybdate tetrahydrate is 0.6-1.0 g; the amount of thiourea is 1.8-3.0 g; the mass ratio of ammonium molybdate tetrahydrate to thiourea is 1:3; and the amount of water is 40-60 mL.

8. The method for preparing the friction-reducing and wear-resistant polyamide-imide composite material according to claim 6, characterized in that: In the step (1), the temperature of the hydrothermal reaction is 150-200°C, and the reaction time is 6-12 h.

9. The method for preparing the friction-reducing and wear-resistant polyamide-imide composite material according to claim 6, characterized in that: In the step (3), the curing temperature is 270-320°C and the curing time is 3-8 hours.

10. Use of the friction-reducing and wear-resistant polyamide-imide composite material according to any one of claims 1 to 5 or the friction-reducing and wear-resistant polyamide-imide composite material prepared by the preparation method according to any one of claims 6 to 9, characterized in that: Application as anti-friction and wear-resistant material in mechanical engineering materials.

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