Preparation process and application of high-temperature-resistant and wear-resistant polymer composite material

Abstract

The invention discloses a preparation process of a high-temperature-resistant and wear-resistant polymer composite material, which comprises the following preparation steps: (1) selecting polyether-ether-ketone as matrix resin, and drying the matrix resin at 150 DEG C for 4 hours; (2) preparing porous sphere-like boron carbide ceramic powder; (3) carrying out surface treatment on the prepared porous sphere-like boron carbide ceramic powder; and (4) uniformly mixing the boron carbide ceramic powder subjected to surface treatment in the step (3) and polyether-ether-ketone in a mild mixing manner, compounding with carbon fibers, and extruding and granulating by using a double-screw extruder to obtain the high-temperature-resistant and wear-resistant polymer composite material. Through the mode, the composite material prepared by the method does not contain PFAS chemical substances, is superior to the existing PTFE material in the aspects of wear resistance, environmental protection property, high temperature resistance and the like, and is an ideal reliable PTFE substitute material.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer composite materials, and in particular to a preparation process and application of a high-temperature-resistant and wear-resistant polymer composite material. Background Art

[0002] Perfluorinated and polyfluoroalkyl substances (hereinafter referred to as PFAS) are a class of artificially synthesized organic compounds. They have unique properties such as water resistance and high temperature resistance and are widely used in industrial and consumer products. With the deepening of scientific research, people have gradually realized that PFAS will bring a series of environmental and health problems. For example: Although PFAS has extremely high chemical stability and thermal stability, it is difficult to decompose in the natural environment. Even under extreme conditions, it is difficult to be degraded. Once entering the environment, PFAS will exist for a long time in the soil, water and atmosphere, and accumulate through the food chain; at the same time, PFAS is also difficult to metabolize in organisms and will accumulate in fat tissue, blood, liver and other tissues for a long time, which has a great impact on health and the environment. At present, countries are gradually strengthening the supervision and control of PFAS.

[0003] As a member of PFAS, polytetrafluoroethylene (hereinafter referred to as PTFE) is also facing increasingly stringent regulatory requirements. In recent years, the development of high-temperature, wear-resistant and environmentally friendly composite materials that can replace PTFE has gradually become a new topic and new technology. As a reliable substitute for PTFE, it is necessary to meet environmental protection requirements and excellent mechanical properties, wear resistance, fatigue resistance, creep resistance, etc. It aims to directly replace PTFE materials in mechanical structures that need to be used in extreme wear-resistant environments such as high load, high speed, and high temperature. Summary of the Invention

[0004] The main technical problem solved by the present invention is to provide a preparation process of a high-temperature-resistant and wear-resistant polymer composite material. The prepared composite material does not contain PFAS chemicals. At the same time, it is superior to existing PTFE materials in terms of wear resistance, environmental protection and high-temperature resistance. It is an ideal and reliable alternative to PTFE.

[0005] In order to solve the above technical problems, a technical solution adopted by the present invention is to provide a process for preparing a high-temperature resistant and wear-resistant polymer composite material, comprising the following preparation steps:

[0006] (1) Polyetheretherketone was selected as the matrix resin and dried at 150°C for 4 hours;

[0007] (2) Preparation of porous spherical boron carbide ceramic powder;

[0008] (3) performing surface treatment on the prepared porous spherical boron carbide ceramic powder;

[0009] (4) The boron carbide ceramic powder and polyetheretherketone after the surface treatment in the above step (3) are mixed evenly by a gentle mixing method, and then compounded with carbon fiber, and extruded and granulated by a twin-screw extruder to obtain a high-temperature resistant and wear-resistant polymer composite material.

[0010] Preferably, in step (1) above, the viscosity of the polyetheretherketone is selected to be between 200 and 400 Pa.s.

[0011] Preferably, in step (2) above, the method for obtaining the porous spherical boron carbide ceramic powder comprises the following steps:

[0012] A. Mix micron-sized boron carbide ceramic powder, dispersant, adhesive and solvent, and ball-mill into a uniform slurry;

[0013] B. The slurry is atomized into small droplets by spray drying. During the drying process, the solvent on the surface of the droplets evaporates rapidly to form a skeleton structure of the boron carbide particles. At the same time, the solvent and precursor inside escape outward to form porous spherical agglomerates with a nearly hollow interior.

[0014] C. Screen out the porous spherical boron carbide ceramic powder in the required particle size range for post-processing.

[0015] Preferably, the post-treatment process in the above step C is to heat-treat the porous quasi-spherical boron carbide ceramic powder obtained above in an inert atmosphere at a temperature below 800° C. and keep the temperature for a certain period of time to perform solidification and debinding treatment.

[0016] Preferably, in the above step (3), the process of surface treatment of the porous spherical boron carbide ceramic powder is to place the boron carbide ceramic powder in concentrated sulfuric acid and react at 80°C for 4 hours to introduce carboxyl functional groups on the surface of the boron carbide ceramic powder.

[0017] Preferably, in the above step (4), in order to improve the compounding strong bonding effect, the carbon fibers are pretreated before compounding.

[0018] Preferably, the carbon fiber is pretreated by placing it in a water bath of 5% hydrogen peroxide and 3% glacial acetic acid at 80° C. for half an hour, rinsing it with deionized water, and then drying it.

[0019] Preferably, in order to ensure the integrity of the structure of the porous spherical boron carbide ceramic powder, in the above step (4), the porous spherical boron carbide ceramic powder and the polyetheretherketone mixture are evenly mixed in a mass percentage of 1:1, and then the remaining polyetheretherketone and carbon fiber are injected through the side feed port.

[0020] In order to solve the above technical problems, another technical solution adopted by the present invention is to provide a high temperature resistant and wear resistant polymer composite material for use in gears, bearings and bushings in extreme wear environments.

[0021] The beneficial effects of the present invention are:

[0022] The high-temperature and wear-resistant polymer composite material developed by the present invention is intended to directly replace PTFE materials for use in gears, bearings, and bushings that require extreme wear resistance in high-load, high-speed, and high-temperature environments. It must not only meet composite environmental requirements, but also have excellent mechanical properties, wear resistance, fatigue resistance, and creep resistance, while also being able to be industrialized in terms of processing technology and processes.

[0023] The main technical means adopted by the present invention is to select polyetheretherketone as the matrix resin, utilize its own excellent mechanical properties, thermal stability, chemical stability and wear resistance, and combine it with surface-treated porous spherical boron carbide ceramic powder and carbon fiber for compounding and synergistically, thereby improving the injection molding performance and mechanical properties of the composite material while maintaining its light weight and easy processing characteristics. The entire composite production process effectively avoids the use of and does not produce chemicals containing PFAS. Compared with the existing PTFE material, it is more environmentally friendly and has less impact on the environment. The composite material obtained by the present invention has a lower density on the one hand, which is more in line with the existing lightweight demand, and at the same time has good fluidity and injection moldability, and is suitable for injection molding processing; compared with the existing method of adding nanoparticles, the preparation process of the present invention is more advantageous and more effective; therefore, the composite material obtained by the preparation process of the present invention is superior to the existing PTFE material, is an ideal alternative material, and has good technical promotion value. DETAILED DESCRIPTION

[0024] The preferred embodiments of the present invention are described in detail below so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more precise definition of the protection scope of the present invention.

[0025] Example

[0026] This embodiment is processed according to the following preparation process:

[0027] Main raw material selection:

[0028] 1. Polyetheretherketone, with a viscosity of 400 Pa.s, purchased from Dongguan Yisike Plastic, model 150GL15;

[0029] 2. Boron carbide ceramic powder: average particle size 5 μm, purchased from Jinmeng New Materials, model JM-B4C-1;

[0030] 3. Ammonium polyacrylate dispersant: purchased from BASF. AA4040 model;

[0031] 4. Polyvinyl alcohol or polyacrylate adhesive: purchased from Dow Chemical B-98 model.

[0032] First, prepare the slurry:

[0033] 8.2 kg of polyetheretherketone particles were selected and dried at 150°C for 4 hours to remove moisture for later use; the above-mentioned boron carbide ceramic powder, ammonium polyacrylate dispersant, polyvinyl alcohol adhesive and isopropyl alcohol solvent were selected and added to a ball mill in proportion, and ball-milled into a uniform slurry;

[0034] Then, the porous treatment is carried out:

[0035] The prepared stable slurry is fed into a spray drying tower through a peristaltic pump. The slurry is dispersed into fine droplets by an atomizer (rotating atomizing disk or pressure / two-fluid nozzle) at the top of the drying tower. Inert gas is introduced from the top or bottom of the tower and contacts the droplets in the same or countercurrent direction. The solvent on the surface of the droplets evaporates rapidly to form a relatively dense shell. The internal solvent diffuses and evaporates outward, eventually forming spherical agglomerates with large pores or even nearly hollow inside. The dried agglomerates are collected at the bottom of the drying tower and sieved to obtain porous spherical boron carbide ceramic powder with the desired particle size range. The powder is then heat-treated at 800°C in an inert atmosphere and kept warm for 2 hours for curing and binder removal to remove organic components.

[0036] Next, the porous spherical boron carbide ceramic powder obtained above was added to concentrated sulfuric acid and reacted at 80°C for 4 hours to introduce carboxyl functional groups on the surface of the boron carbide ceramic powder, thereby improving its compatibility with polyetheretherketone. At this time, 0.8 kg of porous spherical boron carbide ceramic powder was obtained.

[0037] In order to improve the strong bonding effect of the compounding, the above-purchased carbon fiber was pretreated before compounding. The pretreatment process was to place it in a water bath at 80°C for half an hour with 5% hydrogen peroxide and 3% glacial acetic acid, rinse it with deionized water and then dry it to obtain 1 kg of carbon fiber.

[0038] In order to ensure that the porous spherical boron carbide ceramic powder is not destroyed and can be mixed evenly with other raw materials, the surface-treated porous spherical boron carbide ceramic powder and polyetheretherketone are mixed evenly by a gentle mixing method. At the same time, in order to reduce the influence of shear force, the porous spherical boron carbide ceramic powder and polyetheretherketone mixture are first mixed evenly in a mass percentage of 1:1, that is, 0.8 kg of porous spherical boron carbide ceramic powder and 0.8 kg of polyetheretherketone are mixed evenly, and then the remaining 7.4 kg of polyetheretherketone and 1 kg of carbon fiber are injected through the side feeding port, and then extruded and granulated through a twin-screw extruder to obtain an injection-molded high-temperature resistant and wear-resistant polymer composite material, and performance testing is subsequently carried out to verify the experimental results.

[0039] The performance of the products prepared by the present invention is illustrated below by examples and comparative examples. In the comparative example, a PTFE material of product model PTFE 8B purchased from Shanghai Youzi Plastic Co., Ltd. is selected. The samples of this example and the comparative example are the same in size and shape and are subjected to comparative tests under the same conditions. The results are as follows:

[0040]

[0041]

[0042] It can be seen from the above data that under the same test conditions, the polymer composite material obtained by the present invention is significantly superior to the existing conventional PTFE material in terms of mechanical properties. For example, the performance data of tensile strength, tensile modulus, flexural strength and flexural modulus are many times or even dozens of times stronger than the existing PTFE material. At the same time, the density is lower than the existing PTFE material, and it has superior mechanical strength while retaining lightweight performance.

[0043] Furthermore, for the above-mentioned PTFE material and the products made from the embodiments of the present invention, samples of standard size were made. The samples to be tested were placed on a testing device, and the corresponding rotational speed, friction speed, and load were set. The testing device was started, and the samples were rubbed under the set conditions. The wear conditions at different PV values ​​were recorded. To reflect the influence of temperature, this embodiment selected two environmental test temperatures: room temperature of 23°C and high temperature of 205°C. At the same time, to fully reflect the wear resistance, this embodiment selected three different PV values ​​under different loads and rotational speeds, that is, the product of load per unit area and friction speed. The test data is as follows:

[0044]

[0045]

[0046] From the above data, it can be seen intuitively that: when the room temperature is 23°C, using the PV value under high load and speed, the higher the PV test value, the more obvious the wear resistance advantage of the embodiment of the present invention; when the temperature is adjusted to a high temperature of 203°C, the PV values ​​under different high loads and speeds are also tested. The existing PTFE has softened and failed at a PV value of 75,000, and relevant tests cannot be performed. However, the wear resistance of the composite material prepared by the present invention is still superior, which is sufficient to demonstrate that the composite material obtained by the present invention can still exhibit excellent wear resistance in extreme wear-resistant environments of high load, high speed and high temperature, and maintain the continuous temperature and excellent durability of the product quality. Therefore, the polymer composite obtained by the preparation method of the present invention can be used as an ideal PTFE substitute material.

[0047] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A process for preparing a high-temperature-resistant and wear-resistant polymer composite material, characterized in that: The method comprises the following preparation steps: (1) Polyetheretherketone was selected as the matrix resin and dried at 150°C for 4 hours; (2) Preparation of porous spherical boron carbide ceramic powder; (3) performing surface treatment on the prepared porous spherical boron carbide ceramic powder; (4) The porous spherical boron carbide ceramic powder and polyetheretherketone after the surface treatment in step (3) are mixed evenly by a gentle mixing method, and then compounded with carbon fiber, and extruded and granulated by a twin-screw extruder to obtain a high-temperature resistant and wear-resistant polymer composite material.

2. The process for preparing a high-temperature-resistant and wear-resistant polymer composite material according to claim 1, characterized in that: In the above step (1), the viscosity of the polyetheretherketone is selected to be between 200 and 400 Pa.s.

3. The high temperature resistant and wear resistant polymer composite material according to claim 1, characterized in that: In the above step (2), the method for obtaining the porous spherical boron carbide ceramic powder comprises the following steps: A. Mix micron-sized boron carbide ceramic powder, dispersant, adhesive and solvent, and ball-mill into a uniform slurry; B. The slurry is atomized into small droplets by spray drying. During the drying process, the solvent on the surface of the droplets evaporates rapidly to form a skeleton structure of the boron carbide particles. At the same time, the solvent and precursor inside escape outward to form porous spherical agglomerates with a nearly hollow interior. C. Screen out the porous spherical boron carbide ceramic powder in the required particle size range for post-processing.

4. The high temperature resistant and wear resistant polymer composite material according to claim 3, characterized in that: The post-treatment process in the above step C is to heat-treat the porous quasi-spherical boron carbide ceramic powder obtained above in an inert atmosphere at a temperature below 1000° C. and keep the temperature for a certain period of time to perform solidification and debinding treatment.

5. The high temperature resistant and wear resistant polymer composite material according to claim 1, characterized in that: In the above step (3), the process of surface treatment of the porous spherical boron carbide ceramic powder is to place the boron carbide ceramic powder in concentrated sulfuric acid and react at 80° C. for 4 hours to introduce carboxyl functional groups on the surface of the boron carbide ceramic powder.

6. The high temperature resistant and wear resistant polymer composite material according to claim 1, characterized in that: In the above step (4), in order to improve the compounding strong bonding effect, the carbon fiber is pretreated before compounding.

7. The high temperature resistant and wear resistant polymer composite material according to claim 6, characterized in that: The carbon fiber is pretreated by placing it in a water bath at 80° C. for half an hour using 5% hydrogen peroxide and 3% glacial acetic acid, followed by rinsing with deionized water and drying.

8. The high temperature resistant and wear resistant polymer composite material according to claim 1, characterized in that: In order to ensure the integrity of the porous spherical boron carbide ceramic powder structure, in the above step (4), the porous spherical boron carbide ceramic powder and the polyetheretherketone mixture are evenly mixed in a mass percentage of 1:1, and then the remaining polyetheretherketone and carbon fiber are injected through the side feeding port.

9. Use of the high temperature resistant and wear resistant polymer composite material according to any one of claims 1 to 8 in gears, bearings and bushings in extreme wear environments.

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