Ultrahigh molecular weight polyethylene powder and preparation method thereof

Abstract

The invention discloses ultra-high molecular weight polyethylene powder and a preparation method thereof, and belongs to the technical field of high polymer materials. Adding a silane coupling agent KH570 into an ethanol water solution to obtain hydrolysate; adding mineral powder into water to form a suspension, adding the hydrolysate, heating in a water bath, filtering, washing and drying to obtain the grafted mineral powder. Secondly, the fine powder is soaked in a dopamine hydrochloride aqueous solution for pretreatment, sequentially soaked in a sensitizing solution and an activating solution for treatment, then soaked in a growth solution for treatment, cleaned and dried, and modified powder is obtained. And finally, uniformly mixing the modified powder and the grafted mineral powder to obtain the ultra-high molecular weight polyethylene powder. Compared with the prior art, the interface adhesion strength, the compression strength, the tribological performance and the impact toughness of the ultra-high molecular weight polyethylene powder are remarkably improved through the unique fiber structure of the sepiolite powder and the copper sulfate, so that the ultra-high molecular weight polyethylene powder shows excellent comprehensive performance under various working conditions, and has important application value.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to an ultra-high molecular weight polyethylene powder and its preparation method. Background Technology

[0002] Ultra-high molecular weight polyethylene (UHMWPE) is widely used in numerous industrial fields, such as medical devices, aerospace, and automotive manufacturing, due to its excellent wear resistance, low coefficient of friction, and good self-lubricating properties. However, UHMWPE also has some limitations, such as relatively low mechanical strength, difficult processing, and poor interfacial bonding with other materials due to its low surface energy. These issues limit its further application in some high-performance applications.

[0003] To address these issues, researchers have attempted to modify UHMWPE using various methods. Filler modification is a commonly used approach, involving the addition of various fillers, such as mineral powders and metal oxides, to the UHMWPE matrix to improve its mechanical properties and wear resistance. However, traditional filler modification methods often suffer from uneven filler dispersion and poor interfacial compatibility, resulting in unsatisfactory modification effects.

[0004] In recent years, the development of nanotechnology has provided new ideas for the modification of UHMWPE. Introducing nanomaterials into the UHMWPE matrix can significantly improve its mechanical and tribological properties. For example, Chinese patent application CN113845743A discloses a method for preparing polyethylene containing nanomaterials, which involves mixing nano-copper particles and nano-tungsten carbide with UHMWPE powder to prepare a composite material with high impact toughness and low wear rate. However, the dispersion and interfacial bonding of nanomaterials in this method remain a key issue.

[0005] In addition, surface modification technology has been widely applied to the modification of UHMWPE. For example, Chinese patent application CN118085497A discloses a composite lubricating material and its preparation method, which improves the surface energy and interfacial bonding force with other materials by grafting silane coupling agents onto the surface of UHMWPE. However, this method mainly focuses on surface modification, and its effect on improving the overall mechanical properties and wear resistance of the material is limited.

[0006] In summary, although some methods for modifying UHMWPE exist in the existing technology, problems such as uneven filler dispersion, poor interfacial compatibility, and unsatisfactory modification effects still exist. Therefore, developing a UHMWPE modification method that can effectively solve these problems has significant scientific and practical value. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention aims to provide an ultra-high molecular weight polyethylene powder and its preparation method.

[0008] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0009] A method for preparing ultra-high molecular weight polyethylene powder includes the following steps:

[0010] Step 1: Adjust the pH of the ethanol aqueous solution, add silane coupling agent KH570 to carry out the hydrolysis reaction, and obtain the hydrolysate; add mineral powder to water to form a suspension, add the hydrolysate and heat in a water bath, filter, wash and dry to obtain grafted mineral powder;

[0011] Step 2: Immerse UHMWPE fine powder in a pH-adjusted dopamine hydrochloride aqueous solution for pretreatment to obtain pretreated powder; immerse the pretreated powder in sensitization solution and activation solution in sequence to obtain activated powder; immerse the activated powder in growth solution for static water bath treatment, ultrasonic cleaning and drying to obtain modified powder.

[0012] Step 3: Mix the modified powder prepared in step 2 and the grafted mineral powder prepared in step 1 evenly to obtain the ultra-high molecular weight polyethylene powder.

[0013] Preferably, the preparation method of the ultra-high molecular weight polyethylene powder is as follows, in parts by weight:

[0014] Step 1: Adjust the pH of 80-120 parts of 85-95wt% ethanol aqueous solution to 3-5; then add 1-3 parts of KH570, stir and let stand for 4-8 hours to obtain hydrolysate; take 15-25 parts of mineral powder and add to 200-400 parts of water, stir for 20-40 minutes to form a suspension, add 80-120 parts of hydrolysate, heat in a water bath, filter and wash to remove unreacted substances, and dry to obtain grafted mineral powder;

[0015] Step 2: Adjust the pH to 8-9 with a 1-2 g / L dopamine hydrochloride aqueous solution. Immerse 80-120 g of UHMWPE fine powder in 800-1200 parts of dopamine hydrochloride aqueous solution, stir at a constant temperature of 25-35℃ for 12-48 h, rinse with water to obtain pretreated powder, and dry. Add 15-25 parts of stannous chloride and 15-25 parts of 8-12 mol / L hydrochloric acid to 500-1000 parts of water to obtain a sensitizing solution. Immerse the pretreated powder in the sensitizing solution. The sensitized powder is treated with a sensitizing solution for 2-8 minutes and then rinsed with water. 0.05-0.2 parts palladium chloride and 10-20 parts 8-12 mol / L hydrochloric acid are added to 500-1000 parts water to obtain an activation solution. The sensitized powder is immersed in the activation solution for 2-8 minutes and then rinsed with water to obtain activated powder. The activated powder is then immersed in 800-1200 parts growth solution in a static water bath, followed by ultrasonic cleaning with water and drying to obtain modified powder.

[0016] Step 3: Mix 90-99 parts of the modified powder prepared in Step 2 and 1-10 parts of the grafted mineral powder prepared in Step 1 at a rotation speed of 100-300 r / min to obtain the ultra-high molecular weight polyethylene powder.

[0017] In step 1, the pH of the ethanol-water solution is adjusted using glacial acetic acid.

[0018] In step 1, the water bath heating temperature is 50-70℃ for 3-5 hours.

[0019] In step 2, the pH is adjusted using Tris-HCl buffer solution.

[0020] In step 2, the static water bath is a static water bath at 90-98℃ for 10-20 minutes.

[0021] The mineral powder is at least one of montmorillonite powder, hydrotalcite powder, sepiolite powder, and diatomaceous earth powder.

[0022] The growth solution comprises the following components: 0.1-0.2 mol / L transition metal salt, 0.005-0.02 mol / L ascorbic acid, 0.005-0.02 mol / L sodium dodecyl sulfate, and 2-4 wt% ammonia.

[0023] The transition metal salt is at least one of tin tetrachloride, copper sulfate, and cobalt sulfate.

[0024] The functions of each substance in this invention are as follows:

[0025] Glacial acetic acid was used to adjust the pH of the ethanol-water solution to ensure effective hydrolysis of KH570.

[0026] KH570 (silane coupling agent) reacts with the hydroxyl groups on the surface of sepiolite after hydrolysis, thereby enhancing its interfacial bonding with the polymer.

[0027] Sepiolite powder, as a mineral filler, enhances the rigidity and wear resistance of composite materials after silane modification.

[0028] Dopamine hydrochloride forms a polydopamine coating on the UHMWPE surface, providing metal chelation sites to promote subsequent activation.

[0029] Stannous chloride is used as a reducing agent to reduce Pd 2+ It is reduced to Pd nanoparticles, forming catalytic sites.

[0030] Palladium chloride provides Pd 2+ Ions, after reduction, catalyze the growth of CuO on the surface of UHMWPE by copper sulfate.

[0031] Copper sulfate is converted into nano-CuO under Pd catalysis, which imparts antibacterial properties and optimizes friction performance.

[0032] Ascorbic acid reduction of Cu 2+ To regulate the crystallization process and morphology of CuO.

[0033] Sodium dodecyl sulfate, as a surfactant, controls the lateral growth of CuO nanosheets, forming a sheet-like structure.

[0034] Ammonia provides an alkaline environment.

[0035] Compared with the prior art, the present invention has the following beneficial technical effects:

[0036] 1) This invention utilizes the unique high aspect ratio fiber structure of sepiolite powder, grafted with KH570 silane, to form a dense network on the surface. This network anchors the UHMWPE matrix through a combination of chemical bonding and mechanical interlocking. This significantly improves interfacial adhesion strength, effectively avoids problems such as interlayer slippage, and thus enhances the overall performance of the material.

[0037] 2) In this invention, copper sulfate generates nanosheet CuO under specific conditions, which fills the gaps between UHMWPE molecular chains. This pinning effect inhibits molecular chain slippage and improves compressive strength. During friction, the sheet-like structure forms a continuous transfer film covering the grinding balls, reducing the coefficient of friction and significantly optimizing the tribological properties of the material.

[0038] 3) This invention achieves spatial complementarity by combining the macroscopic reinforcing framework of sepiolite fibers with the microscopic functional modification of CuO nanosheets. The fiber network provides a load-bearing skeleton, while CuO fills defects and optimizes interfacial energy, thereby achieving a synergistic improvement in mechanical properties, tribological characteristics, and toughness, enabling the material to exhibit excellent comprehensive performance under various working conditions.

[0039] 4) The ultra-high molecular weight polyethylene powder prepared by this invention has significantly better compressive strength, wear rate and notched impact toughness than unmodified UHMWPE products. It is suitable for preparing high-performance engineering parts, such as bearings, gears, guide rail bushings, bulletproof armor liners, etc., and can significantly extend the service life of related products. Detailed Implementation

[0040] Main source of materials:

[0041] UHMWPE fine powder, item number: HL-300M, molecular weight 1.5-3 million, Ningbo Honglang New Material Technology Co., Ltd.

[0042] Sepiolite powder, 100-2000 mesh, item number: KX-HPS, Hebei Kexu Building Materials Co., Ltd.

[0043] Dopamine hydrochloride, product number: 3665, Jiangxi Muzan Biotechnology Co., Ltd.

[0044] Diatomaceous earth powder, specification: 325 mesh, Tuoyi New Materials (Guangzhou) Co., Ltd.

[0045] Hydrotalcite powder, product model: 2:1, Hebei Jiegui Mineral Products Co., Ltd.

[0046] Montmorillonite powder, product specifications: 400 mesh, Guangying New Materials (Guangzhou) Co., Ltd.

[0047] Tris-HCl buffer, catalog number: BB040, Shanghai Ruji Biotechnology Development Co., Ltd.

[0048] All other raw materials used in the embodiments and comparative examples of this invention are commercially available products.

[0049] Example 1

[0050] A method for preparing ultra-high molecular weight polyethylene powder is as follows:

[0051] Step 1: Add glacial acetic acid to adjust the pH of 100g of 90wt% ethanol aqueous solution to 4; then add 2g of KH570, stir and let stand for 6h to obtain hydrolysate; take 20g of sepiolite powder and add it to 300g of water, stir for 30min to form a suspension, add 100g of hydrolysate, heat in a 60℃ water bath for 4h, filter, wash to remove unreacted substances, and dry to obtain grafted mineral powder;

[0052] Step 2: Adjust the pH of the 1.5 g / L dopamine hydrochloride aqueous solution to 8.5 using Tris-HCl buffer. Immerse 100 g of UHMWPE fine powder in 1000 g of dopamine hydrochloride aqueous solution, stir at 30°C for 24 h, rinse with water to obtain pretreated powder, and dry at 30°C for 24 h. Add 20 g of stannous chloride and 20 g of 10 mol / L hydrochloric acid to 800 g of water to obtain sensitization solution. Immerse the pretreated powder in the sensitization solution for 5 min, then rinse with water to obtain sensitized powder. Then add 0.1 g of palladium chloride and 15 g of... 10 mol / L hydrochloric acid was added to 800 g of water to obtain an activation solution; the sensitized powder was immersed in the activation solution for 5 min, then rinsed with water to obtain activated powder; the activated powder was immersed in 1000 g of growth solution, subjected to a static water bath at 95℃ for 15 min, then ultrasonically cleaned with water and dried to obtain modified powder; the growth solution contained the following components: 0.15 mol / L copper sulfate, 0.01 mol / L ascorbic acid, 0.01 mol / L sodium dodecyl sulfate, and 3 wt% ammonia water;

[0053] Step 3: Mix 96g of the modified powder prepared in Step 2 and 4g of the grafted mineral powder prepared in Step 1 at a rotation speed of 200r / min to obtain the ultra-high molecular weight polyethylene powder.

[0054] Example 2

[0055] A method for preparing ultra-high molecular weight polyethylene powder is as follows:

[0056] Step 1: Add glacial acetic acid to adjust the pH of 100g of 90wt% ethanol aqueous solution to 4; then add 2g of KH570, stir and let stand for 6h to obtain hydrolysate; take 20g of diatomaceous earth powder and add it to 300g of water, stir for 30min to form a suspension, add 100g of hydrolysate, heat in a 60℃ water bath for 4h, filter, wash to remove unreacted substances, and dry to obtain grafted mineral powder;

[0057] Step 2: Adjust the pH of the 1.5 g / L dopamine hydrochloride aqueous solution to 8.5 using Tris-HCl buffer. Immerse 100 g of UHMWPE fine powder in 1000 g of dopamine hydrochloride aqueous solution, stir at 30°C for 24 h, rinse with water to obtain pretreated powder, and dry at 30°C for 24 h. Add 20 g of stannous chloride and 20 g of 10 mol / L hydrochloric acid to 800 g of water to obtain sensitization solution. Immerse the pretreated powder in the sensitization solution for 5 min, then rinse with water to obtain sensitized powder. Then add 0.1 g of palladium chloride and 15 g of... 10 mol / L hydrochloric acid was added to 800 g of water to obtain an activation solution; the sensitized powder was immersed in the activation solution for 5 min, then rinsed with water to obtain activated powder; the activated powder was immersed in 1000 g of growth solution, subjected to a static water bath at 95℃ for 15 min, then ultrasonically cleaned with water and dried to obtain modified powder; the growth solution contained the following components: 0.15 mol / L copper sulfate, 0.01 mol / L ascorbic acid, 0.01 mol / L sodium dodecyl sulfate, and 3 wt% ammonia water;

[0058] Step 3: Mix 96g of the modified powder prepared in Step 2 and 4g of the grafted mineral powder prepared in Step 1 at a rotation speed of 200r / min to obtain the ultra-high molecular weight polyethylene powder.

[0059] Example 3

[0060] A method for preparing ultra-high molecular weight polyethylene powder is as follows:

[0061] Step 1: Add glacial acetic acid to adjust the pH of 100g of 90wt% ethanol aqueous solution to 4; then add 2g of KH570, stir and let stand for 6h to obtain hydrolysate; take 20g of hydrotalcite powder and add it to 300g of water, stir for 30min to form a suspension, add 100g of hydrolysate, heat in a 60℃ water bath for 4h, filter and wash to remove unreacted substances, and dry to obtain grafted mineral powder;

[0062] Step 2: Adjust the pH of the 1.5 g / L dopamine hydrochloride aqueous solution to 8.5 using Tris-HCl buffer. Immerse 100 g of UHMWPE fine powder in 1000 g of dopamine hydrochloride aqueous solution, stir at 30°C for 24 h, rinse with water to obtain pretreated powder, and dry at 30°C for 24 h. Add 20 g of stannous chloride and 20 g of 10 mol / L hydrochloric acid to 800 g of water to obtain sensitization solution. Immerse the pretreated powder in the sensitization solution for 5 min, then rinse with water to obtain sensitized powder. Then add 0.1 g of palladium chloride and 15 g of... 10 mol / L hydrochloric acid was added to 800 g of water to obtain an activation solution; the sensitized powder was immersed in the activation solution for 5 min, then rinsed with water to obtain activated powder; the activated powder was immersed in 1000 g of growth solution, subjected to a static water bath at 95℃ for 15 min, then ultrasonically cleaned with water and dried to obtain modified powder; the growth solution contained the following components: 0.15 mol / L copper sulfate, 0.01 mol / L ascorbic acid, 0.01 mol / L sodium dodecyl sulfate, and 3 wt% ammonia water;

[0063] Step 3: Mix 96g of the modified powder prepared in Step 2 and 4g of the grafted mineral powder prepared in Step 1 at a rotation speed of 200r / min to obtain the ultra-high molecular weight polyethylene powder.

[0064] Example 4

[0065] A method for preparing ultra-high molecular weight polyethylene powder is as follows:

[0066] Step 1: Add glacial acetic acid to adjust the pH of 100g of 90wt% ethanol aqueous solution to 4; then add 2g of KH570, stir and let stand for 6h to obtain hydrolysate; take 20g of montmorillonite powder and add it to 300g of water, stir for 30min to form a suspension, add 100g of hydrolysate, heat in a 60℃ water bath for 4h, filter, wash to remove unreacted substances, and dry to obtain grafted mineral powder;

[0067] Step 2: Adjust the pH of the 1.5 g / L dopamine hydrochloride aqueous solution to 8.5 using Tris-HCl buffer. Immerse 100 g of UHMWPE fine powder in 1000 g of dopamine hydrochloride aqueous solution, stir at 30°C for 24 h, rinse with water to obtain pretreated powder, and dry at 30°C for 24 h. Add 20 g of stannous chloride and 20 g of 10 mol / L hydrochloric acid to 800 g of water to obtain sensitization solution. Immerse the pretreated powder in the sensitization solution for 5 min, then rinse with water to obtain sensitized powder. Then add 0.1 g of palladium chloride and 15 g of... 10 mol / L hydrochloric acid was added to 800 g of water to obtain an activation solution; the sensitized powder was immersed in the activation solution for 5 min, then rinsed with water to obtain activated powder; the activated powder was immersed in 1000 g of growth solution, subjected to a static water bath at 95℃ for 15 min, then ultrasonically cleaned with water and dried to obtain modified powder; the growth solution contained the following components: 0.15 mol / L copper sulfate, 0.01 mol / L ascorbic acid, 0.01 mol / L sodium dodecyl sulfate, and 3 wt% ammonia water;

[0068] Step 3: Mix 96g of the modified powder prepared in Step 2 and 4g of the grafted mineral powder prepared in Step 1 at a rotation speed of 200r / min to obtain the ultra-high molecular weight polyethylene powder.

[0069] Example 5

[0070] A method for preparing ultra-high molecular weight polyethylene powder is as follows:

[0071] Step 1: Add glacial acetic acid to adjust the pH of 100g of 90wt% ethanol aqueous solution to 4; then add 2g of KH570, stir and let stand for 6h to obtain hydrolysate; take 20g of sepiolite powder and add it to 300g of water, stir for 30min to form a suspension, add 100g of hydrolysate, heat in a 60℃ water bath for 4h, filter, wash to remove unreacted substances, and dry to obtain grafted mineral powder;

[0072] Step 2: Adjust the pH of the 1.5 g / L dopamine hydrochloride aqueous solution to 8.5 using Tris-HCl buffer. Immerse 100 g of UHMWPE fine powder in 1000 g of dopamine hydrochloride aqueous solution, stir at 30°C for 24 h, rinse with water to obtain pretreated powder, and dry at 30°C for 24 h. Add 20 g of stannous chloride and 20 g of 10 mol / L hydrochloric acid to 800 g of water to obtain sensitization solution. Immerse the pretreated powder in the sensitization solution for 5 min, then rinse with water to obtain sensitized powder. Then add 0.1 g of palladium chloride and 15 g of... 10 mol / L hydrochloric acid was added to 800 g of water to obtain an activation solution; the sensitized powder was immersed in the activation solution for 5 min, then rinsed with water to obtain activated powder; the activated powder was immersed in 1000 g of growth solution, subjected to a static water bath at 95℃ for 15 min, then ultrasonically cleaned with water and dried to obtain modified powder; the growth solution contained the following components: 0.15 mol / L cobalt sulfate, 0.01 mol / L ascorbic acid, 0.01 mol / L sodium dodecyl sulfate, and 3 wt% ammonia water;

[0073] Step 3: Mix 96g of the modified powder prepared in Step 2 and 4g of the grafted mineral powder prepared in Step 1 at a rotation speed of 200r / min to obtain the ultra-high molecular weight polyethylene powder.

[0074] Example 6

[0075] A method for preparing ultra-high molecular weight polyethylene powder is as follows:

[0076] Step 1: Add glacial acetic acid to adjust the pH of 100g of 90wt% ethanol aqueous solution to 4; then add 2g of KH570, stir and let stand for 6h to obtain hydrolysate; take 20g of sepiolite powder and add it to 300g of water, stir for 30min to form a suspension, add 100g of hydrolysate, heat in a 60℃ water bath for 4h, filter, wash to remove unreacted substances, and dry to obtain grafted mineral powder;

[0077] Step 2: Adjust the pH of the 1.5 g / L dopamine hydrochloride aqueous solution to 8.5 using Tris-HCl buffer. Immerse 100 g of UHMWPE fine powder in 1000 g of dopamine hydrochloride aqueous solution, stir at 30°C for 24 h, rinse with water to obtain pretreated powder, and dry at 30°C for 24 h. Add 20 g of stannous chloride and 20 g of 10 mol / L hydrochloric acid to 800 g of water to obtain sensitization solution. Immerse the pretreated powder in the sensitization solution for 5 min, then rinse with water to obtain sensitized powder. Then add 0.1 g of palladium chloride and 15 g of... 10 mol / L hydrochloric acid was added to 800 g of water to obtain an activation solution; the sensitized powder was immersed in the activation solution for 5 min, then rinsed with water to obtain activated powder; the activated powder was immersed in 1000 g of growth solution, subjected to a static water bath at 95℃ for 15 min, then ultrasonically cleaned with water and dried to obtain modified powder; the growth solution contained the following components: 0.15 mol / L tin tetrachloride, 0.01 mol / L ascorbic acid, 0.01 mol / L sodium dodecyl sulfate, and 3 wt% ammonia water;

[0078] Step 3: Mix 96g of the modified powder prepared in Step 2 and 4g of the grafted mineral powder prepared in Step 1 at a rotation speed of 200r / min to obtain the ultra-high molecular weight polyethylene powder.

[0079] Comparative Example 1

[0080] A method for preparing ultra-high molecular weight polyethylene powder is as follows:

[0081] Step 1: Add glacial acetic acid to adjust the pH of 100g of 90wt% ethanol aqueous solution to 4; then add 2g of KH570, stir and let stand for 6h to obtain hydrolysate; take 20g of attapulgite powder and add it to 300g of water, stir for 30min to form a suspension, add 100g of hydrolysate, heat in a 60℃ water bath for 4h, filter, wash to remove unreacted substances, and dry to obtain grafted mineral powder;

[0082] Step 2: Adjust the pH of the 1.5 g / L dopamine hydrochloride aqueous solution to 8.5 using Tris-HCl buffer. Immerse 100 g of UHMWPE fine powder in 1000 g of dopamine hydrochloride aqueous solution, stir at 30°C for 24 h, rinse with water to obtain pretreated powder, and dry at 30°C for 24 h. Add 20 g of stannous chloride and 20 g of 10 mol / L hydrochloric acid to 800 g of water to obtain sensitization solution. Immerse the pretreated powder in the sensitization solution for 5 min, then rinse with water to obtain sensitized powder. Then add 0.1 g of palladium chloride and 15 g of... 10 mol / L hydrochloric acid was added to 800 g of water to obtain an activation solution; the sensitized powder was immersed in the activation solution for 5 min, then rinsed with water to obtain activated powder; the activated powder was immersed in 1000 g of growth solution, subjected to a static water bath at 95℃ for 15 min, then ultrasonically cleaned with water and dried to obtain modified powder; the growth solution contained the following components: 0.15 mol / L copper sulfate, 0.01 mol / L ascorbic acid, 0.01 mol / L sodium dodecyl sulfate, and 3 wt% ammonia water;

[0083] Step 3: Mix 96g of the modified powder prepared in Step 2 and 4g of the grafted mineral powder prepared in Step 1 at a rotation speed of 200r / min to obtain the ultra-high molecular weight polyethylene powder.

[0084] Comparative Example 2

[0085] A method for preparing ultra-high molecular weight polyethylene powder is as follows:

[0086] Step 1: Add glacial acetic acid to adjust the pH of 100g of 90wt% ethanol aqueous solution to 4; then add 2g of KH570, stir and let stand for 6h to obtain hydrolysate; take 20g of sepiolite powder and add it to 300g of water, stir for 30min to form a suspension, add 100g of hydrolysate, heat in a 60℃ water bath for 4h, filter, wash to remove unreacted substances, and dry to obtain grafted mineral powder;

[0087] Step 2: Adjust the pH of the 1.5 g / L dopamine hydrochloride aqueous solution to 8.5 using Tris-HCl buffer. Immerse 100 g of UHMWPE fine powder in 1000 g of dopamine hydrochloride aqueous solution, stir at 30°C for 24 h, rinse with water to obtain pretreated powder, and dry at 30°C for 24 h. Add 20 g of stannous chloride and 20 g of 10 mol / L hydrochloric acid to 800 g of water to obtain sensitization solution. Immerse the pretreated powder in the sensitization solution for 5 min, then rinse with water to obtain sensitized powder. Then add 0.1 g of palladium chloride and 15 g of... 10 mol / L hydrochloric acid was added to 800 g of water to obtain an activation solution; the sensitized powder was immersed in the activation solution for 5 min, then rinsed with water to obtain activated powder; the activated powder was immersed in 1000 g of growth solution, subjected to a static water bath at 95℃ for 15 min, then ultrasonically cleaned with water and dried to obtain modified powder; the growth solution contained the following components: 0.15 mol / L zinc acetate dihydrate, 0.01 mol / L ascorbic acid, 0.01 mol / L sodium dodecyl sulfate, and 3 wt% ammonia water;

[0088] Step 3: Mix 96g of the modified powder prepared in Step 2 and 4g of the grafted mineral powder prepared in Step 1 at a rotation speed of 200r / min to obtain the ultra-high molecular weight polyethylene powder.

[0089] Test Example 1

[0090] Compression strength test:

[0091] The ultra-high molecular weight polyethylene powder prepared in the embodiments and comparative examples of this invention was hot-pressed using a mold and a CREE-6014D-4 flatbed hot press at 200°C and 12MPa to prepare sample sizes of Φ11mm×11mm. The compressive properties of the material samples were tested using a universal electronic testing machine. During the test, the maximum compression of the sample was 60% of its height, and the compression rate was 1mm / min.

[0092] Friction performance test:

[0093] Friction and wear test: Friction tests were conducted using a UMT rotary friction and wear testing machine. Test conditions: load 20N, rotation radius 5mm, speed 100rpm, silicon nitride balls as the grinding pair, 3wt% NaCl solution for lubrication, and test duration 1.5h. After the test, the wear tracks were observed using a white light interferometer, and the wear track volume was measured.

[0094] The test results are shown in Table 1.

[0095] Table 1

[0096] Experimental protocol Compressive strength / MPa <![CDATA[Wear rate / [mm 3 / (N·m)]]]> Example 1 185.2 <![CDATA[3.57×10 -8 <!-- 6 -->]]> Example 2 178.5 <![CDATA[4.20×10 -8 ]]> Example 3 172.8 <![CDATA[4.75×10 -8 ]]> Example 4 168.3 <![CDATA[5.10×10 -8 ]]> Example 5 175.6 <![CDATA[4.35×10 -8 ]]> Example 6 176.5 <![CDATA[4.32×10 -8 ]]> Comparative Example 1 165.4 <![CDATA[5.55×10 -8 ]]> Comparative Example 2 176.7 <![CDATA[4.25×10 -8 ]]>

[0097] Test Example 2

[0098] Impact toughness test:

[0099] According to GB / T1043.1-2008 "Determination of impact properties of simply supported beams of plastics - Part 1: Non-instrumental impact testing", the ultra-high molecular weight polyethylene powder prepared in the embodiments and comparative examples of this invention was processed into the required specimens, and the notched impact strength of the simply supported beams was tested. The results are shown in Table 2.

[0100] Table 2

[0101] Experimental protocol <![CDATA[Impact toughness (KJ / m 2 )]]> Example 1 115.6 Example 2 111.8 Example 3 109.5 Example 4 103.8 Example 5 111.0 Example 6 104.1 Comparative Example 1 101.3 Comparative Example 2 105.6

[0102] Example 1 of this invention, employing a combination of sepiolite powder and copper sulfate, exhibits optimal performance in compressive strength, wear rate, and impact toughness. The mechanism may lie in the following: the unique high aspect ratio fiber structure of sepiolite, after grafting with KH570 silane, forms a dense Si-O-Si network on its surface, anchoring the UHMWPE matrix through a combination of chemical bonding and mechanical interlocking. The Mg-OH polar groups enriched on its surface form a strong hydrogen bond network with the polyethylene molecular chains, significantly enhancing interfacial adhesion strength. The three-dimensional fiber network uniformly disperses stress, avoiding localized stress concentration. Simultaneously, the high rigidity of the fiber skeleton effectively bears the load during friction, reducing the penetration depth of micro-protrusions, while dissipating energy under impact loads through a dual mechanism of fiber pull-out and fracture.

[0103] Copper sulfate may be regulated to generate nanosheet CuO, whose unique morphology achieves a triple function of mechanical enhancement, friction optimization, and toughness regulation. CuO nanosheets fill the gaps between UHMWPE molecular chains, inhibiting molecular chain slippage through the pinning effect and improving compressive strength. The sheet-like structure forms a continuous transfer film covering silicon nitride grinding balls during friction, reducing the coefficient of friction. CuO's plastic deformation ability buffers the stress at the crack tip, and oxygen vacancy defects promote electronic interaction with polyethylene, enhancing interfacial toughness.

[0104] The macroscopic reinforcing framework of sepiolite fibers and the microscopic functional modification of CuO nanosheets form spatial complementarity. The fiber network provides a load-bearing skeleton, while CuO fills defects and optimizes interfacial energy; synergistic bonding enhances interfacial stability.

Claims

1. A method for preparing ultra-high molecular weight polyethylene powder, characterized in that, Includes the following steps: Step 1: Adjust the pH of the ethanol aqueous solution, add silane coupling agent KH570 to carry out the hydrolysis reaction, and obtain the hydrolysate; add mineral powder to water to form a suspension, add the hydrolysate and heat in a water bath, filter, wash and dry to obtain grafted mineral powder; Step 2: Immerse the UHMWPE fine powder in a pH-adjusted dopamine hydrochloride aqueous solution for pretreatment to obtain pretreated powder; The pretreated powder was sequentially immersed in sensitization solution and activation solution to obtain activated powder; the activated powder was then immersed in growth solution for static water bath treatment, ultrasonically cleaned and dried to obtain modified powder. Step 3: Mix the modified powder prepared in step 2 and the grafted mineral powder prepared in step 1 evenly to obtain the ultra-high molecular weight polyethylene powder.

2. The method for preparing ultra-high molecular weight polyethylene powder as described in claim 1, characterized in that, The preparation method is as follows, in parts by weight: Step 1: Adjust the pH of 80-120 parts of 85-95wt% ethanol aqueous solution to 3-5; then add 1-3 parts of KH570, stir and let stand for 4-8 hours to obtain the hydrolysate; Take 15-25 parts of mineral powder and add it to 200-400 parts of water. Stir for 20-40 minutes to form a suspension. Add 80-120 parts of hydrolysate, heat in a water bath, filter, wash to remove unreacted substances, and dry to obtain grafted mineral powder. Step 2: Adjust the pH to 8-9 with a 1-2 g / L dopamine hydrochloride aqueous solution. Immerse 80-120 g of UHMWPE fine powder in 800-1200 parts of dopamine hydrochloride aqueous solution, stir at a constant temperature of 25-35℃ for 12-48 h, rinse with water to obtain pretreated powder, and dry. Add 15-25 parts of stannous chloride and 15-25 parts of 8-12 mol / L hydrochloric acid to 500-1000 parts of water to obtain a sensitizing solution. Immerse the pretreated powder in the sensitizing solution. The sensitized powder is treated with a sensitizing solution for 2-8 minutes and then rinsed with water. 0.05-0.2 parts palladium chloride and 10-20 parts 8-12 mol / L hydrochloric acid are added to 500-1000 parts water to obtain an activation solution. The sensitized powder is immersed in the activation solution for 2-8 minutes and then rinsed with water to obtain activated powder. The activated powder is then immersed in 800-1200 parts growth solution in a static water bath, followed by ultrasonic cleaning with water and drying to obtain modified powder. Step 3: Mix 90-99 parts of the modified powder prepared in Step 2 and 1-10 parts of the grafted mineral powder prepared in Step 1 at a rotation speed of 100-300 r / min to obtain the ultra-high molecular weight polyethylene powder.

3. The method for preparing ultra-high molecular weight polyethylene powder as described in claim 1 or 2, characterized in that, In step 1, the pH of the ethanol-water solution is adjusted using glacial acetic acid.

4. The method for preparing ultra-high molecular weight polyethylene powder as described in claim 1 or 2, characterized in that, In step 1, the water bath heating temperature is 50-70℃ for 3-5 hours.

5. The method for preparing ultra-high molecular weight polyethylene powder as described in claim 1 or 2, characterized in that, In step 2, the pH is adjusted using Tris-HCl buffer solution.

6. The method for preparing ultra-high molecular weight polyethylene powder as described in claim 1 or 2, characterized in that, In step 2, the static water bath is a static water bath at 90-98℃ for 10-20 minutes.

7. The method for preparing ultra-high molecular weight polyethylene powder as described in claim 1 or 2, characterized in that, The mineral powder is at least one of montmorillonite powder, hydrotalcite powder, sepiolite powder, and diatomaceous earth powder.

8. The method for preparing ultra-high molecular weight polyethylene powder as described in claim 1 or 2, characterized in that, The growth solution comprises the following components: 0.1-0.2 mol / L transition metal salt, 0.005-0.02 mol / L ascorbic acid, 0.005-0.02 mol / L sodium dodecyl sulfate, and 2-4 wt% ammonia.

9. The method for preparing ultra-high molecular weight polyethylene powder as described in claim 8, characterized in that, The transition metal salt is at least one of tin tetrachloride, copper sulfate, and cobalt sulfate.

10. An ultra-high molecular weight polyethylene powder, characterized in that, It is prepared by the preparation method described in any one of claims 1-9.