Water-walking polymer friction pair material modified by oxidized coal pitch nanocarbon material and preparation method thereof

Abstract

The application discloses a kind of oxidized coal pitch nanocarbon material modified water-related polymer friction pair materials and preparation method, belong to polymer material technical field.The water-related polymer friction pair material of the present application is made of soluble oxidized pitch nanomaterial of formic acid / hydrogen peroxide oxidation system oxidation coal pitch and ultra-high molecular weight polyethylene matrix.The present application utilizes the gap of polymer molecular chain of soluble oxidized pitch nanomaterial of ultra-small structure, and plastic rheology and adhesive wear of material are reduced in friction process by steric hindrance and interface anchoring effect;Combination of the "nanometer reinforcing network" formed by uniform dispersion can effectively transfer friction stress, avoid the matrix cracking caused by local stress concentration;While the nanometer size of soluble oxidized pitch nanomaterial and carbon-based characteristics give it unique dynamic lubrication function, its surface abundant functional groups can form high density, strong adhesion transfer film, significantly improve the wear resistance and service life of composite material.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a water-contact polymer friction pair material modified with oxidized coal tar nanocarbon material and its preparation method. Background Technology

[0002] Traditional metal friction pair materials are highly susceptible to electrochemical reactions with other media in aquatic environments, leading to severe corrosion and accelerating frictional damage to moving parts. Furthermore, they require lubrication with oil or grease during operation, consuming significant amounts of mineral oil and precious metal resources. Considering resource conservation and environmental protection, the environmental pollution caused by leaks of oil / grease lubricants used in metal friction pairs is a significant concern. Therefore, self-lubricating polymers are widely used as friction pair materials to replace metals in water-lubricated bearings, guide rails, gaskets, and other moving parts in marine equipment and underwater devices.

[0003] Ultra-high molecular weight polyethylene (UHMWPE) possesses excellent self-lubricating properties, chemical inertness, and good mechanical properties. It is also non-toxic, environmentally friendly, and has extremely low water absorption, making it a potential friction pair material for marine engineering equipment. However, the high wear characteristics of UHMWPE limit its widespread application in water-related engineering equipment, necessitating further optimization and modification.

[0004] For example, in Chinese invention patent publication CN117186527A, the applicant provides a UHMWPE friction-reducing and wear-resistant composite material based on cadmium phosphate modification and its preparation method. This scheme utilizes the irregular lamellar stacked structure of cadmium phosphate particles, allowing the polymer matrix molecular chains to enter the depressions on the cadmium phosphate surface during molding to form an interlocking structure, making it less prone to peeling off during friction. After entering the friction interface, it is broken into cadmium phosphate nanosheets under shear force, forming a lubricating protective film, thereby effectively reducing damage to the friction surface of the composite material. Similarly, in Chinese invention patent publication CN117343414A, the applicant provides a polymer friction pair material for water-related applications and its preparation method. This scheme utilizes rough-surfaced granular cobalt phosphate to increase the interfacial bonding force with the matrix, making it less prone to peeling off during friction, thus enhancing the polymer matrix's ability to withstand friction loads and shear forces. The two-dimensional lamellar cobalt phosphate can form a lubricating film at the friction interface, simultaneously improving the friction-reducing and wear-resistant performance, reliability, and service life of the composite material.

[0005] In further research on ultra-high molecular weight polyethylene (UHMWPE) composites, the applicant discovered that current fillers used for UHMWPE modification still have many shortcomings. Traditional inorganic fillers are inexpensive, but they lack surface functional groups, resulting in poor polarity matching with the non-polar UHMWPE matrix. The interface can only form weak van der Waals forces, and high filler content is required to achieve the modification effect. Although non-carbon-based nanofillers possess nanoscale effects, their single surface reaction sites and high surface energy make them prone to irreversible agglomeration in high-viscosity UHMWPE melts, easily forming stress concentration points in the matrix.

[0006] In contrast, carbon nanofillers, with their π-π interactions between the carbon core structure and polymer molecular chains, coupled with abundant surface-modifiable functional groups, readily form excellent interfacial bonding effects, possessing the potential to synergistically enhance the mechanical and tribological properties of polymers, making them a key research focus in the modification of ultra-high molecular weight polyethylene. However, while traditional carbon nanofillers (such as graphene and carbon nanotubes) can effectively improve the mechanical and tribological properties of polymers, they suffer from limited surface groups and restricted interfacial bonding effects, and the raw materials are expensive, resulting in high costs for engineering applications.

[0007] In summary, this paper presents a novel technical approach for modifying ultra-high molecular weight polyethylene, which solves the aforementioned problems in existing technologies and is of great significance for expanding the application of polymer friction pair materials. Summary of the Invention

[0008] In view of the above-mentioned deficiencies of the prior art, the purpose of this invention is to provide a polymer friction pair material and preparation method for water-related working conditions, so as to achieve the preparation of polymer friction pair material with excellent friction reduction and wear resistance at low cost, optimize the compatibility and bonding ability of modified material with matrix, and greatly improve the tribological properties of friction pair material for water-related engineering equipment under harsh working conditions and extend its service life.

[0009] To achieve the above objectives, the technical solution provided by the present invention is as follows: In a first aspect of the present invention, a water-contact polymer friction pair material is provided, comprising: The matrix and the reinforcing phase are: the matrix is ​​ultra-high molecular weight polyethylene, and the reinforcing phase is soluble oxidized coal tar pitch (OCTP) nanomaterial; the soluble oxidized coal tar pitch nanomaterial is obtained by oxidizing and stripping coal tar pitch using an oxidation system composed of formic acid and hydrogen peroxide.

[0010] Preferably, the content of ultra-high molecular weight polyethylene is 95.0 wt.% to 99.9 wt.%, and the content of soluble oxidized asphalt nanomaterial is 0.1 wt.% to 5.0 wt.%.

[0011] Preferably, the ultra-high molecular weight polyethylene has a molecular weight of 1.5 million to 3 million and a particle size of 80 to 120 mesh.

[0012] Preferably, the particle size of the soluble oxidized asphalt nanomaterial is 40~100 nm.

[0013] Preferably, the preparation method of the soluble oxidized asphalt nanomaterial includes the following steps: Formic acid and hydrogen peroxide were mixed at a mass ratio of (1~5):10 to obtain an oxidizing solution with a hydrogen peroxide concentration of 25%~30%. Powdered coal tar pitch was added to a sufficient amount of the oxidizing solution and reacted at 30~50℃ for 20~30 h. After the reaction was completed, the crude product was centrifuged and the supernatant was collected. The solvent in the supernatant was then removed and dried to obtain soluble oxidized asphalt nanomaterials.

[0014] In practice, coal tar pitch is oxidized and exfoliated using formic acid (analytical grade) / hydrogen peroxide (25%~30%, mass fraction). The resulting soluble oxidized asphalt nanomaterials have abundant hydroxyl and carboxyl functional groups on their surface, exhibiting good solubility in solvents such as ethanol. As presented in one or more embodiments of this invention, the coal tar pitch raw material is first pulverized to a particle size of no more than 100 mesh and reacted under stirring. When the reaction has proceeded for a predetermined time, it is cooled to room temperature. The supernatant obtained by centrifugation is then subjected to rotary evaporation to remove the solvent, and subsequently dried in a vacuum drying oven at 80~100℃. Under the guidance of the above process, those skilled in the art can select appropriate equipment or conventional operations according to actual conditions to achieve the purpose of preparing soluble oxidized asphalt nanomaterials.

[0015] In a second aspect of the present invention, a method for preparing the water-contact polymer friction pair material of the first aspect of the present invention is provided, comprising the following steps: (1) Prepare raw materials according to the component ratio; add soluble oxidized asphalt nanomaterials to ethanol, and treat with ultrasound to obtain a dispersion of soluble oxidized asphalt nanomaterials; (2) Add ultra-high molecular weight polyethylene to the soluble oxidized asphalt nanomaterial dispersion, and then ball mill it to obtain a mixed powder; (3) The mixed powder is hot-pressed and cured to form the target shape, thus obtaining a water-contact polymer friction pair material.

[0016] Preferably, in step (1), the mass ratio of the soluble oxidized asphalt nanomaterial to ethanol is 1:(10~20).

[0017] Those skilled in the art can select appropriate ultrasonic or ball milling parameters according to actual conditions or needs to achieve the purpose of promoting uniform dispersion or refinement of materials. For example, in actual operation, ultrasonic power of 100 W can be used for 20 to 40 minutes, or ball milling can be performed at 500 rpm for 2 to 4 hours with a ball-to-material ratio of 2:1.

[0018] Preferably, in step (3), the hot-press curing molding includes the following steps: The dry blended powder is loaded into a mold and pre-compressed at a pressure of 1.4~2.0 MPa 2~5 times, each time for 3~5 minutes. After pre-compression, it is cured and molded. The mold temperature is set to 140~180℃ and held for 60~120 minutes, then heating is stopped. The mold is placed in the air to cool naturally. When the temperature is 107~113℃, a holding pressure of 0.7~1.1 MPa is applied. When the temperature cools to 97~103℃, a holding pressure of 2.1~2.5 MPa is applied. When the temperature cools to 87~93℃, a holding pressure of 4.4~4.8 MPa is applied. When the temperature cools to 77~83℃, a holding pressure of 8~12 MPa is applied. When the mold cools to room temperature naturally, the pressure is released and the mold is demolded to obtain the water-contact polymer friction pair material.

[0019] In a third aspect of the invention, the application of the water-contact polymer friction pair material of the first aspect of the invention or the water-contact polymer friction pair material prepared by the preparation method of the second aspect of the invention is provided, including: as a friction pair material used in friction components of hydraulic machinery, ships, and underwater equipment.

[0020] Based on the above technical solutions, the design concept and principle of this invention are as follows: Coal tar pitch, as a widely available and inexpensive carbon-based material, possesses abundant aromatic structures and potential for modification. However, raw coal tar pitch exhibits poor solubility and dispersibility, making it difficult to use directly as a polymer modifier. To address this technical problem, this invention employs a formic acid / hydrogen peroxide oxidation system for efficient oxidative modification of coal tar pitch, preparing soluble oxidized pitch nanomaterials. These nanomaterials possess characteristics such as ultra-small size and abundant surface functional groups, exhibiting good compatibility with ultra-high molecular weight polyethylene.

[0021] Based on this, this invention utilizes the unique structure and properties of soluble oxidized asphalt nanomaterials. It designs a method to leverage the ultra-small nanostructures that occupy the gaps between ultra-high molecular weight polyethylene (UHMWPE) molecular chains, reducing plastic rheology and adhesive wear during friction through steric hindrance and interfacial anchoring effects. Compared to existing inorganic fillers that form interlocking structures or increase roughness to enhance bonding, this invention, under the aforementioned rheological properties, allows the uniformly dispersed "nano-reinforced network" of soluble oxidized asphalt nanomaterials to effectively transfer frictional stress, preventing matrix cracking caused by localized stress concentration. Simultaneously, the nanoscale size and carbon-based characteristics of soluble oxidized asphalt nanomaterials endow them with unique dynamic lubrication functions. The abundant hydroxyl and carboxyl functional groups on their surface can form a highly dense and strongly adhered transfer film on the steel surface, significantly improving the friction-reducing and wear-resistant properties of the composite material.

[0022] The water-resistant polymer friction pair material of the present invention can be mass-produced through a simple process. Soluble oxidized asphalt nanomaterials and ultra-high molecular weight polyethylene powder are ultrasonically dispersed and mechanically mixed, and then cured and molded by hot pressing to form a friction-reducing and wear-resistant polymer material for water-resistant engineering equipment. The corresponding components can be obtained by using molds of the required shape and structure.

[0023] In summary, this invention utilizes the multifunctional properties of soluble oxidized asphalt nanomaterials. Their ultra-small size and surface functional groups enhance the interfacial bonding with the ultra-high molecular weight polyethylene (UHMWPE) matrix, making them less prone to peeling during friction and improving the UHMWPE matrix's ability to withstand frictional loads and shear forces. The nano-reinforcing network formed by the soluble oxidized asphalt nanomaterials effectively disperses frictional stress, preventing matrix cracking. Simultaneously, their carbon-based properties, dynamic lubrication function, and the transfer film formed on the steel surface synergistically improve the friction-reducing and wear-resistant properties of the composite material. The prepared polymer friction pair material is of great significance for improving the reliability of polymer friction pair components and extending their service life under water-related conditions.

[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) This invention uses ultra-high molecular weight polyethylene as the base material, and modifies it by adding soluble oxidized asphalt nanomaterials prepared by a formic acid / hydrogen peroxide oxidation system. The ultra-high molecular weight polyethylene friction-reducing and wear-resistant polymer material samples for water-related engineering equipment are obtained by ultrasonic dispersion, mechanical blending, and hot pressing. The ultra-small nanostructure of the soluble oxidized asphalt nanomaterials can occupy the gaps between the ultra-high molecular weight polyethylene molecular chains. Through steric hindrance and interfacial anchoring effects, it reduces the plastic rheology and adhesive wear of the material during friction, thereby improving the structural stability of the material.

[0025] (2) In this invention, soluble oxidized asphalt nanomaterials are uniformly dispersed in ultra-high molecular weight polyethylene matrix to form a “nano-reinforced network”, which can effectively transfer frictional stress, avoid matrix cracking caused by local stress concentration, and significantly improve the mechanical properties and wear resistance of composite materials; at the same time, the carbon-based characteristics and nano-size of soluble oxidized asphalt nanomaterials endow them with excellent dynamic lubrication function, further reducing friction loss.

[0026] (3) The surface of soluble oxidized asphalt nanomaterials contains abundant functional groups such as hydroxyl and carboxyl groups, which have extremely strong interfacial adsorption capacity. During the friction process, it is easy to physically adsorb on the surface of the steel friction pair. Under the combined action of frictional heat and pressure, it can undergo tribochemical reaction with the steel surface to form a highly dense and strongly adhered transfer film, which significantly improves the friction reduction and wear resistance of the composite material.

[0027] (4) The soluble oxidized asphalt nanomaterial used in this invention uses coal tar pitch as raw material, which is widely available and inexpensive. It solves the problems of poor solubility and poor dispersibility of the original coal tar pitch and significantly reduces the preparation cost of the modified composite material. At the same time, the preparation method is simple and convenient to operate, without the need for complex equipment and harsh reaction conditions. It is suitable for large-scale industrial production and the preparation process is green and environmentally friendly with no harmful gas emissions.

[0028] (5) Under water-related lubrication conditions such as seawater or freshwater, the water-related polymer friction pair material prepared by this invention has significantly reduced friction coefficient and wear rate compared with pure ultra-high molecular weight polyethylene material, and has better self-lubricating and wear-resistant properties. It can be widely used in friction components in fields such as hydraulic machinery, ships, and underwater equipment, and has broad application prospects. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the oxidation of soluble oxidized asphalt nanomaterials. Figure 2 The images are scanning electron microscope (SEM) images of soluble oxidized asphalt nanomaterials, with an inset showing the particle size distribution of the soluble oxidized asphalt nanomaterials. Figure 3 The Fourier transform infrared spectroscopy (FTIR) spectra of ultra-high molecular weight polyethylene and water-contact polymer friction pair materials are shown, with embedded insets showing photographs of actual water-contact polymer friction pair materials. Figure 4 This diagram shows the friction coefficients of ultra-high molecular weight polyethylene and different types of water-contaminated polymer friction pair materials. Detailed Implementation

[0030] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0031] In the following embodiments: Coal tar pitch: Ningxia Baichuan New Materials Co., Ltd., softening point: 78.8℃, medium-temperature coal tar pitch; Ultra-high molecular weight polyethylene: Beijing Zhuping Plastic Products Co., Ltd., molecular weight 2-3 million.

[0032] Example 1 This embodiment provides a water-contact polymer friction pair material, which is prepared using the following method: (1) Prepare raw materials according to the addition amount of soluble oxidized asphalt nanomaterials of 1.0 wt.%; weigh 0.15 g of soluble oxidized asphalt nanomaterials, add them to 10 mL of ethanol, place them in an ultrasonic cleaner (power 250 W, frequency 40 kHz), and ultrasonically disperse for 30 min to obtain a uniformly dispersed soluble oxidized asphalt nanomaterial dispersion. (2) Add 15 g of ultra-high molecular weight polyethylene powder to the soluble oxidized asphalt nanomaterial dispersion, stir evenly, place it in a planetary ball mill, mill at 400 r / min, ball-to-material ratio 2:1, mechanically blend for 3 h to obtain mixed powder; (3) The mixed powder was placed in a drying oven at 55°C and dried for 12 h to remove moisture. After drying, it was placed in a mold and hot-pressed to solidify and form a water-contact polymer friction pair material.

[0033] like Figure 1 As shown, the preparation steps of the soluble oxidized asphalt nanomaterial in this embodiment are as follows: Weigh out 2 g of coal tar pitch, 300 mL of formic acid, and 30 mL of hydrogen peroxide. Crush the coal tar pitch to 80 mesh and place it in a three-necked flask. Add formic acid and hydrogen peroxide, and react at 40°C with a stirring rate of 800 rpm for 24 h, maintaining a constant stirring speed throughout the reaction. After the reaction is complete, cool the reaction solution to room temperature, transfer it to a centrifuge tube, and centrifuge at 8000 r / min for 10 min. Take the supernatant and place it in a rotary evaporator. Remove the solvent by rotary evaporation at 60°C and 0.08 MPa. Place the obtained solid in a vacuum drying oven and dry at 90°C for 24 h to obtain a brown powder, which is oxidized coal tar pitch carbon nanomaterial (OCTP) with a particle size of 80-120 nm and a yield of approximately 50%.

[0034] The microstructure of soluble oxidized asphalt nanomaterials was observed using a scanning electron microscope. Figure 2The morphological characteristics and particle size of soluble oxidized asphalt nanomaterials were shown. The results showed that spherical nanoparticles with a particle size of about 56.8 nm could be obtained by hydrogen peroxide / formic acid oxidation system.

[0035] The pure ultra-high molecular weight polyethylene and the prepared water-contact polymer friction pair material (OCTP-UHMWPE composite material) were characterized by Fourier transform infrared spectroscopy. The results are as follows: Figure 3 As shown. Compared to pure ultra-high molecular weight polyethylene, water-contact polymer friction pair materials at 3400 cm... -1 1710 cm -1 and 1250 cm -1 The presence of distinct characteristic absorption peaks at the ions is attributed to the stretching vibrations of hydroxyl (-OH), carbonyl (C=O), and ether (CO) groups, respectively, confirming that soluble oxidized asphalt nanomaterials have been successfully introduced into the ultra-high molecular weight polyethylene matrix. Figure 2 The embedded photos show that the water-contact polymer friction pair material has a uniform color and a smooth surface without obvious protrusions or defects, indicating that the soluble oxidized asphalt nanomaterials are uniformly dispersed in the ultra-high molecular weight polyethylene matrix, and the two have excellent interfacial compatibility.

[0036] Example 2 This embodiment provides a water-contact polymer friction pair material made of 3.0 wt.% soluble oxidized asphalt nanomaterial modified with ultra-high molecular weight polyethylene.

[0037] This embodiment uses the same soluble oxidized asphalt nanomaterial as in Example 1. 0.45 g of the soluble oxidized asphalt nanomaterial was weighed and added to 10 mL of ethanol, and ultrasonically dispersed for 30 min to obtain a soluble oxidized asphalt nanomaterial dispersion. 15 g of ultra-high molecular weight polyethylene powder was added to the soluble oxidized asphalt nanomaterial dispersion, and after stirring evenly, the water-contact polymer friction pair material was prepared using the same ball milling, drying, and hot pressing process as in Example 1.

[0038] Example 3 This embodiment provides a water-contact polymer friction pair material made of 5.0 wt.% soluble oxidized asphalt nanomaterial modified with ultra-high molecular weight polyethylene.

[0039] This embodiment uses the same soluble oxidized asphalt nanomaterial as in Example 1. 0.75 g of the soluble oxidized asphalt nanomaterial was weighed and added to 10 mL of ethanol, and ultrasonically dispersed for 30 min to obtain a soluble oxidized asphalt nanomaterial dispersion. 15 g of ultra-high molecular weight polyethylene powder was added to the soluble oxidized asphalt nanomaterial dispersion, and after stirring evenly, the water-contact polymer friction pair material was prepared using the same ball milling, drying, and hot pressing process as in Example 1.

[0040] Those skilled in the art can also adjust the corresponding preparation parameters under preferred conditions according to actual conditions or needs, and all can achieve the corresponding objectives of the present invention.

[0041] Comparative Example 1 This comparative example uses pure ultra-high molecular weight polyethylene material without any modifiers. It is used directly for tribological testing under water-related conditions as a blank control.

[0042] Test Example 1 This test example demonstrates the tribological properties of the friction pair materials in the embodiments and comparative examples to study the application performance of the water-contact polymer friction pair materials of the present invention. This test example can also be considered an application embodiment of the water-contact polymer friction pair materials.

[0043] Water immersion testing was conducted using a reciprocating friction and wear testing machine (model: MFT-5000, Rtec, USA). The lower specimen was a prepared modified composite material sample (50 mm diameter; 5 mm height), and the upper specimen was a GCr15 bearing steel ball (8 mm diameter, HRC 60~62 hardness). Before testing, the specimens were ultrasonically cleaned with anhydrous ethanol for 10 min and dried before installation. Deionized water was used as the test medium and poured into the contact area of ​​the friction pair. The test parameters were set as follows: load 20 N, reciprocating stroke 10 mm, sliding speed 0.1 m / s, test time 30 min, and ambient temperature 25℃.

[0044] The friction coefficient was automatically recorded by computer during the test. After the test, the sample was removed, ultrasonically cleaned with anhydrous ethanol, dried, and then the depth and width of the wear tracks were measured using a three-dimensional optical profilometer to calculate the wear volume.

[0045] Figure 4 The curves showing the change of friction coefficient over time for each sample under wading conditions are presented. The friction coefficient of pure ultra-high molecular weight polyethylene (UHMWPE) (Comparative Example 1) was relatively high in the initial stage (approximately 0.70), then gradually decreased and stabilized at around 0.61, indicating that pure UHMWPE has limited lubrication performance and severe wear under wading conditions. After adding 1 wt.% soluble oxidized asphalt nanomaterial, the friction coefficient decreased to around 0.52 and remained stable; when 3 wt.% soluble oxidized asphalt nanomaterial was added, the friction coefficient rapidly decreased to 0.43, and the curve was stable without fluctuations, indicating that the soluble oxidized asphalt nanomaterial formed a stable and firm lubrication transfer film at the friction interface, significantly improving the friction reduction and wear resistance of the composite material.

[0046] Based on the structural characteristics and tribological test results of soluble oxidized asphalt nanomaterials, the modification mechanism is as follows: (1) Chemical adsorption and interfacial anchoring: The surface of soluble oxidized asphalt nanomaterials contains abundant functional groups such as hydroxyl and carboxyl groups, which can form hydrogen bonds with ultra-high molecular weight polyethylene molecular chains, and at the same time form weak coordination bonds with iron atoms on the surface of steel friction pairs, so that soluble oxidized asphalt nanomaterials are firmly adsorbed on the interface, enhancing the interfacial bonding force. (2) Nano-reinforcement effect: The ultra-small nanostructure (20~100 nm) of soluble oxidized asphalt nanomaterials is uniformly dispersed in the ultra-high molecular weight polyethylene matrix to form a "nano-reinforcement network", which effectively transmits frictional stress and avoids matrix cracking caused by local stress concentration. (3) Dynamic lubrication and transfer film effect: The carbon-based properties of soluble oxidized asphalt nanomaterials endow them with excellent dynamic lubrication function. Under the combined action of frictional heat and pressure, soluble oxidized asphalt nanomaterials form a highly dense and strongly adherent transfer film on the surface of the steel friction pair, isolating the friction interface, reducing adhesive wear and plastic rheology, and achieving efficient friction reduction and wear resistance. The synergistic effect of these three factors endows the modified composite material with excellent water-resistant tribological properties.

[0047] In summary, this invention successfully prepared a novel soluble oxidized asphalt nanomaterial. Its synthesis method is simple, its structure is controllable, and its cost is low, solving the problems of poor solubility and dispersibility of traditional coal tar pitch. As a modifier, this material can significantly reduce the friction coefficient and wear volume of ultra-high molecular weight polyethylene (UHMWPE) materials under water-related conditions at extremely low addition levels (1-3 wt.%), and it exhibits good compatibility and stable dispersion with the UHMWPE matrix. This invention provides a new approach for developing efficient and low-cost polymer friction pair materials for water-related conditions, possessing significant application value and industrialization prospects.

[0048] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A water-contact polymer friction pair material, characterized in that, include: The matrix and the reinforcing phase are: the matrix is ​​ultra-high molecular weight polyethylene, and the reinforcing phase is soluble oxidized asphalt nanomaterial; the soluble oxidized asphalt nanomaterial is prepared by oxidizing and stripping coal tar pitch using an oxidation system composed of formic acid and hydrogen peroxide.

2. The water-contact polymer friction pair material according to claim 1, characterized in that: The content of ultra-high molecular weight polyethylene is 95.0 wt.%~99.9 wt.%, and the content of soluble oxidized asphalt nanomaterial is 0.1 wt.%~5.0 wt.%.

3. The water-contact polymer friction pair material according to claim 1, characterized in that: The ultra-high molecular weight polyethylene has a molecular weight of 1.5 million to 3 million.

4. The water-contact polymer friction pair material according to claim 1, characterized in that: The particle size of the ultra-high molecular weight polyethylene is 80~120 mesh.

5. The water-contact polymer friction pair material according to claim 1, characterized in that: The particle size of the soluble oxidized asphalt nanomaterial is 40~100 nm.

6. The water-contact polymer friction pair material according to claim 1, characterized in that, The preparation method of the soluble oxidized asphalt nanomaterial includes the following steps: Formic acid and hydrogen peroxide were mixed at a mass ratio of (1~5):10 to obtain an oxidizing solution with a hydrogen peroxide concentration of 25%~30%. Powdered coal tar pitch was added to a sufficient amount of the oxidizing solution and reacted at 30~50℃ for 20~30 h. After the reaction was completed, the crude product was centrifuged and the supernatant was collected. The solvent in the supernatant was then removed and dried to obtain soluble oxidized asphalt nanomaterials.

7. A method for preparing a water-contact polymer friction pair material as described in any one of claims 1 to 6, characterized in that, Includes the following steps: (1) Prepare raw materials according to the component ratio; add soluble oxidized asphalt nanomaterials to ethanol, and treat with ultrasound to obtain a dispersion of soluble oxidized asphalt nanomaterials; (2) Add ultra-high molecular weight polyethylene to the soluble oxidized asphalt nanomaterial dispersion, and then ball mill it to obtain a mixed powder; (3) The mixed powder is hot-pressed and cured to form the target shape, thus obtaining a water-contact polymer friction pair material.

8. The method for preparing the water-contact polymer friction pair material according to claim 7, characterized in that: In step (1), the mass ratio of the soluble oxidized asphalt nanomaterial to ethanol is 1:(10~20).

9. The method for preparing the water-contact polymer friction pair material according to claim 7, characterized in that, In step (3), the hot-press curing molding includes the following steps: The dry blended powder is loaded into a mold and pre-pressed at 1.4~2.0 MPa for 2~5 times, each time for 3~5 minutes. After pre-pressing, the mold is cured and molded. The mold temperature is set to 140~180℃ and held for 60~120 minutes, then heating is stopped. The mold is placed in the air to cool naturally. When the temperature is 107~113℃, a holding pressure of 0.7~1.1 MPa is applied. When the temperature cools to 97~103℃, a holding pressure of 2.1~2.5 MPa is applied. When the temperature cools to 87~93℃, a holding pressure of 4.4~4.8 MPa is applied. When the temperature cools to 77~83℃, a holding pressure of 8~12 MPa is applied. When the mold cools to room temperature naturally, the pressure is released and the mold is demolded to obtain the water-contact polymer friction pair material.

10. The application of a water-contact polymer friction pair material as described in any one of claims 1 to 6 or a water-contact polymer friction pair material prepared by the preparation method as described in any one of claims 7 to 9, characterized in that, include: It is used as a friction pair material in friction components of hydraulic machinery, ships, and underwater equipment.

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