A manganese phosphate nanosheet modified UHMWPE friction-reducing and wear-resistant composite material and its preparation method

Abstract

This invention discloses a manganese phosphate nanosheet-modified UHMWPE friction-reducing and wear-resistant composite material and its preparation method. First, manganese phosphate trihydrate nanosheets are prepared, then mechanically mixed uniformly with ultra-high molecular weight polyethylene powder. The mixed powder is placed in a mold, and finally, a hot-press molding method is used to heat and melt the mixed powder, followed by solidification. After cooling and demolding, the UHMWPE friction-reducing and wear-resistant composite material is obtained. This invention utilizes the manganese phosphate trihydrate nanosheets to form a manganese phosphate salt film with certain lubricity and heat resistance during friction, effectively reducing material deformation and tearing on the friction surface, thereby improving the friction-reducing and wear-resistant properties of ultra-high molecular weight polyethylene. The prepared UHMWPE friction-reducing and wear-resistant composite material shows a significant reduction in the coefficient of friction, wear track depth, and width under dry friction conditions. When used as a friction material for moving parts, it can greatly improve the reliability and service life of the mating components.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, and relates to a material for manufacturing engineering equipment, specifically to a UHMWPE friction-reducing and wear-resistant composite material modified with manganese phosphate nanosheets and its preparation method. Background Technology

[0002] Friction and wear are ubiquitous in our daily lives, significantly impacting energy consumption, carbon dioxide emissions, and economic costs. Research indicates that studying tribological problems in industries such as transportation and energy can effectively extend the service life of machinery, reduce energy consumption and economic losses, and decrease carbon dioxide emissions, providing new solutions for countries worldwide. In recent years, with the construction of various major engineering projects, higher demands have been placed on the functionality and reliability of various engineering equipment under harsh operating conditions. Therefore, the development of high-performance polymer-based composite materials and the study of their tribological properties are of great significance for the development and application of engineering equipment. Ultra-high molecular weight polyethylene (UHMWPE) possesses excellent self-lubricating properties, chemical inertness, and good mechanical properties, and is widely used as a friction pair component. However, the high wear rate of UHMWPE limits its application in engineering equipment, necessitating further improvements. Traditional layered lubricants such as molybdenum disulfide and graphite exhibit excellent lubrication performance due to their interlayer sliding effect. Manganese phosphate is a widely used and important chemical raw material and intermediate for other materials. It can be used as a phosphating agent in the phosphating treatment of steel products, providing excellent rust prevention. It is also used as a lubricating and protective layer for various weapons and large equipment. Layered manganese phosphate films exhibit excellent lubrication properties and heat resistance. Current research on manganese phosphate mainly focuses on its use as a phosphating agent and as a precursor for lithium manganese phosphate, a cathode material in lithium-ion batteries. There are no systematic reports on its use as a filler in polymer composites to study the tribological properties of the composites. Summary of the Invention

[0003] The purpose of this invention is to provide a friction-reducing and wear-resistant composite material modified with manganese phosphate nanosheets and its preparation method, so as to prepare a composite material with excellent wear resistance, which greatly improves the tribological properties of friction pair materials for engineering equipment under harsh working conditions and extends their service life.

[0004] The UHMWPE friction-reducing and wear-resistant composite material prepared in this invention consists of a UHMWPE matrix material and manganese trihydrate phosphate nanosheets as filler. First, manganese trihydrate phosphate nanosheets are prepared, then mechanically mixed uniformly with UHMWPE powder. Finally, the mixed powder is heated, molded, melted, and solidified using a hot-pressing method. After cooling and demolding, the modified ultra-high molecular weight polyethylene-based UHMWPE friction-reducing and wear-resistant composite material is obtained. This invention utilizes the manganese trihydrate phosphate nanosheets to form a manganese phosphate salt film with certain lubricity and heat resistance during friction, effectively reducing material deformation and tearing on the friction surface, thereby improving the friction-reducing and wear-resistant properties of ultra-high molecular weight polyethylene. The prepared UHMWPE friction-reducing and wear-resistant composite material shows a significant reduction in the coefficient of friction, wear track depth, and width under dry friction conditions. When used as a friction material for moving parts, it can greatly improve the reliability and service life of the mating components.

[0005] The technical solution adopted by the present invention to achieve the above objectives is as follows:

[0006] This invention provides a friction-reducing and wear-resistant composite material of UHMWPE modified with manganese trihydrate phosphate nanosheets, which is composed of ultra-high molecular weight polyethylene and manganese trihydrate phosphate.

[0007] As a preferred option, manganese trihydrate phosphate is a two-dimensional nanosheet structure.

[0008] The ultra-high molecular weight polyethylene and manganese trihydrate phosphate nanosheets described in this invention are both in powder form. First, a divalent manganese salt solution is added to an alkaline buffer solution and reacted completely. Then, the precipitate is separated to obtain manganese trihydrate phosphate nanosheets. Next, the ultra-high molecular weight polyethylene powder and the fully dried manganese trihydrate phosphate nanosheet powder are mechanically mixed and solidified by a hot press to form a friction-reducing and wear-resistant polymer material for engineering equipment. The corresponding components are obtained by using a mold with the required shape and structure.

[0009] This invention also provides a method for preparing a UHMWPE friction-reducing and wear-resistant composite material, comprising the following steps:

[0010] Step 1: Synthesize manganese phosphate trihydrate nanosheets;

[0011] Step 2: Select ultra-high molecular weight polyethylene powder; select manganese phosphate trihydrate nanosheet powder;

[0012] Step 3: Mix the ultra-high molecular weight polyethylene powder and manganese phosphate trihydrate nanosheet powder obtained in Step 2 evenly to form a mixed powder;

[0013] Step 4: Place the mixed powder in the mold, use a hot press to pre-press, then solidify and shape, and finally cool and demold.

[0014] Preferably, the process for producing manganese phosphate nanosheets in step 1 is as follows:

[0015] A divalent manganese salt solution was added to an alkaline buffer solution to form a reaction solution. The reaction solution was sonicated and allowed to stand at room temperature for a period of time. After the reaction was complete, the precipitate was separated and dried thoroughly to obtain manganese phosphate trihydrate nanosheets.

[0016] Preferably, the alkaline buffer solution is prepared by mixing disodium hydrogen phosphate solution and sodium dihydrogen phosphate solution in a ratio of 60:40 to 80:20.

[0017] Preferably, the divalent manganese salt solution is any one or a combination of manganese sulfate solution, manganese chloride solution, and manganese nitrate solution.

[0018] Preferably, the specific steps in step 2 are as follows: weigh a certain amount of raw materials according to the weight ratio and mix them, that is, weigh a certain amount of manganese phosphate trihydrate nanosheets and UHMWPE raw material powder, and mechanically mix them using a planetary ball mill for 1 to 2 hours.

[0019] Preferably, the mixed powder is dried in a drying oven at 66°C before being hot-pressed in the mold.

[0020] Preferably, in step 3, the molding process is as follows: the dried blended powder raw material is loaded into the mold and pre-pressed using a pressure of 20-30 MPa, three times for 3-5 minutes each time; after pre-pressing, curing is performed, the mold temperature is set to 160-180℃, and heating of the mold begins. When the temperature controller shows that the set temperature has been reached, the temperature is maintained for 2-3 hours, and then heating is stopped; the mold is placed in the air to cool naturally. When the temperature controller shows 108-112℃, a pressure of 10-20 MPa is applied for holding; when the temperature cools to 98-102℃, a pressure of 30-40 MPa is applied for holding; when the temperature cools to 88-92℃, a pressure of 70-80 MPa is applied for holding; when the temperature cools to 78-82℃, a pressure of 120-150 MPa is applied for holding; when the mold cools naturally to room temperature, the pressure is released and the mold is demolded.

[0021] Preferably, both UHMWPE and manganese phosphate trihydrate nanosheets are in powder form. The two powder materials are physically blended and then melt-cured in a hot press to prepare a UHMWPE friction-reducing and wear-resistant composite material for engineering equipment.

[0022] Preferably, the content of manganese trihydrate phosphate nanosheets in the UHMWPE friction-reducing and wear-resistant composite material is 5-10 wt.%.

[0023] As a further preferred embodiment, the content of manganese trihydrate phosphate nanosheets in the UHMWPE friction-reducing and wear-resistant composite material is 5-7 wt.%.

[0024] The beneficial effects of this invention are:

[0025] (1) This invention uses ultra-high molecular weight polyethylene (UHMWPE) powder as the base material, and adds manganese trihydrate phosphate nanosheets to it for hot pressing to obtain a UHMWPE friction-reducing and wear-resistant polymer composite material sample for engineering equipment. Because the manganese trihydrate phosphate nanosheets form a manganese phosphate salt film with certain lubricity and heat resistance during friction, it effectively reduces the deformation and tearing of the material on the friction surface, thereby improving the friction-reducing and wear-resistant properties of ultra-high molecular weight polyethylene. When the contents of manganese trihydrate phosphate nanosheets and UHMWPE are 5-10 wt.% and 90-95 wt.%, respectively, the composite material has the lowest coefficient of friction, the best wear resistance, and reduces material loss by more than 50%.

[0026] (2) Under dry friction conditions, the UHMWPE composite material shows a significant change in friction reduction compared to the pure UHMWPE material. Tribological tests were conducted on the UHMWPE polymer composite material under dry friction conditions. The depth and width of the wear tracks on the composite material were lower than those on the pure UHMWPE material, indicating that the UHMWPE composite material has better self-lubricating properties and wear resistance. Attached Figure Description

[0027] Figure 1 These are scanning electron microscope images of manganese phosphate nanosheets prepared in Examples 1-3 of this invention;

[0028] Figure 2 The graph shows the relationship between the friction coefficient and friction time of the UHMWPE friction-reducing and wear-resistant composite material for engineering equipment in this invention under dry friction conditions. In the graph, curve Comparative Example 1 is the friction coefficient curve of the prepared pure UHMWPE material for engineering equipment, and curves Examples 1 to 3 are the friction coefficient curves of the prepared UHMWPE friction-reducing and wear-resistant composite material for engineering equipment.

[0029] Figure 3 The graph shows the average friction coefficient of the UHMWPE friction-reducing and wear-resistant composite materials for engineering equipment prepared in Comparative Example 1 and Examples 1-3 of this invention under dry friction conditions.

[0030] Figure 4 This is a graph showing the relationship between the composition ratio of the UHMWPE friction-reducing and wear-resistant composite material for engineering equipment and the depth and width of the wear tracks under dry friction conditions. The curves in the graph are curves of UHMWPE friction-reducing and wear-resistant composite materials for engineering equipment with different compositions prepared in Comparative Example 1 and Examples 1 to 3, respectively. Detailed Implementation

[0031] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following detailed description, in conjunction with the accompanying drawings and application examples, provides a specific embodiment of the UHMWPE friction-reducing and wear-resistant composite material modified with manganese phosphate nanosheets and its preparation method according to the present invention. The following examples are only used to more clearly illustrate the technical solution of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0032] Comparative Example 1:

[0033] Hot-press curing of ultra-high molecular weight polyethylene (UHMWPE) powder: 100 wt.% of UHMWPE raw material powder was weighed and mechanically ground and blended using a planetary ball mill for 1 hour. The powder was then dried at 66℃ for 3 hours. Next, the molding process was carried out: the dried raw material was loaded into a mold and pre-pressed at 26 MPa for 3 minutes each time. After pre-pressing, curing was performed. The mold temperature was set to 167℃, and heating was started. When the temperature controller showed that the set temperature was reached, the mold was held at that temperature for 2 hours and then heating was stopped. The mold was placed in air to cool naturally. When the temperature controller showed 110℃, a pressure of 12 MPa was applied and held. After cooling to 100℃, a pressure of 37 MPa was applied and held. After cooling to 90℃, a pressure of 75 MPa was applied and held. After cooling to 80℃, a pressure of 142 MPa was applied and held. When the mold cooled naturally to room temperature, the pressure was released and the mold was demolded to obtain UHMWPE friction-reducing and wear-resistant composite material for engineering equipment.

[0034] Example 1:

[0035] S1. Synthesis of manganese phosphate trihydrate nanosheets: Prepare a pH 7.2 0.2 mol / L phosphate buffer solution by mixing 28 mL of 0.2 mol / L sodium dihydrogen phosphate and 72 mL of 0.2 mol / L disodium hydrogen phosphate. Add 0.5 mL of 0.2 mol / L manganese sulfate solution (manganese ion to phosphate ratio: 1:200), sonicate for 5 min, let stand for 48 h, centrifuge to obtain the precipitate, wash twice with distilled water, and dry in a 60℃ oven to obtain manganese phosphate trihydrate nanoflowers. Figure 1 As shown.

[0036] S2. Hot pressing and curing of ultra-high molecular weight polyethylene powder and manganese trihydrate phosphate nanosheet powder: Weigh 5 wt.% of manganese trihydrate phosphate nanosheet raw material and 95 wt.% of UHMWPE raw material powder, and mechanically grind and blend them using a planetary ball mill for 1 hour. Then dry the powder at 64℃ for 3 hours. The molding process is as follows: the dried raw material is loaded into the mold and pre-pressed at 26 MPa for 3 times, each time for 3 minutes; after pre-pressing, curing is carried out, the mold temperature is set to 167℃, the mold is heated, and when the temperature controller shows that the set temperature is reached, the temperature is held for 2 hours and then the heating is stopped; the mold is placed in the air to cool naturally, and when the temperature controller shows 110℃, a pressure of 12 MPa is applied and held; when the temperature cools to 100℃, a pressure of 37 MPa is applied and held; when the temperature cools to 90℃, a pressure of 75 MPa is applied and held; when the temperature cools to 80℃, a pressure of 142 MPa is applied and held; when the mold cools to room temperature naturally, the pressure is released and the mold is demolded to obtain the UHMWPE friction-reducing and wear-resistant composite material for engineering equipment.

[0037] Example 2:

[0038] For the synthesis of S1, manganese phosphate trihydrate nanosheets, please refer to Example 1.

[0039] S2. Hot pressing and curing of ultra-high molecular weight polyethylene powder and manganese trihydrate phosphate nanosheet powder: Weigh 7 wt.% of manganese trihydrate phosphate nanosheet raw material and 93 wt.% of UHMWPE raw material powder, and mechanically grind and blend them using a planetary ball mill for 1 hour. Then dry the powder at 64℃ for 3 hours. The next step is the molding process: the dried raw material is loaded into the mold and pre-pressed at 26 MPa for 3 times, each time for 3 minutes; after pre-pressing, curing is carried out, the mold temperature is set to 167℃, the mold is heated, and when the temperature controller shows that the temperature has reached the set temperature, it is kept at that temperature for 2 hours and then the heating is stopped; the mold is placed in the air to cool naturally, and when the temperature controller shows 110℃, a pressure of 12 MPa is applied and held; when the temperature has cooled to 100℃, a pressure of 37 MPa is applied and held; when the temperature has cooled to 90℃, a pressure of 75 MPa is applied and held; when the temperature has cooled to 80℃, a pressure of 142 MPa is applied and held; when the mold has cooled to room temperature naturally, the pressure is released and the mold is demolded to obtain the UHMWPE friction-reducing and wear-resistant composite material for engineering equipment.

[0040] Example 3:

[0041] For the synthesis of S1, manganese phosphate trihydrate nanosheets, please refer to Example 1.

[0042] S2. Hot pressing and curing of ultra-high molecular weight polyethylene powder and manganese trihydrate phosphate nanosheet powder: Weigh 10 wt.% of manganese trihydrate phosphate nanosheet raw material and 90 wt.% of UHMWPE raw material powder, and mechanically grind and blend them using a planetary ball mill for 1 hour. Then dry the powder at 64℃ for 3 hours. The next step is the molding process: the dried raw material is loaded into the mold and pre-pressed at 26 MPa for 3 times, each time for 3 minutes; after pre-pressing, curing is carried out, the mold temperature is set to 167℃, the mold is heated, and when the temperature controller shows that the temperature has reached the set temperature, it is kept at that temperature for 2 hours and then the heating is stopped; the mold is placed in the air to cool naturally, and when the temperature controller shows 110℃, a pressure of 12 MPa is applied and held; when the temperature has cooled to 100℃, a pressure of 37 MPa is applied and held; when the temperature has cooled to 90℃, a pressure of 75 MPa is applied and held; when the temperature has cooled to 80℃, a pressure of 142 MPa is applied and held; when the mold has cooled to room temperature naturally, the pressure is released and the mold is demolded to obtain the UHMWPE friction-reducing and wear-resistant composite material for engineering equipment.

[0043] The tribological properties of the UHMWPE composite material samples prepared in Comparative Example 1 and Examples 1-3 were compared, and the results are shown in the figure. Figures 2-4 .

[0044] The tribological test under dry friction conditions was carried out on a pin-disc friction and wear tester. The mating parts of the kinematic pair were φ8mm balls made of GCr15 bearing steel. The working load was 100N, the speed was 0.66m / s (rotation speed 300r / min), the rotation radius was 21mm, and the working time was 30min.

[0045] like Figures 2 to 4 As shown, compared with the pure UHMWPE sample of Comparative Example 1 and the UHMWPE composite material samples of Examples 1-3, the coefficient of friction of the polymer composite material is reduced, with a maximum reduction of about 30%. The depth and width of the wear tracks are also significantly reduced, with a maximum reduction of more than 50%. Because the manganese phosphate trihydrate nanosheets form a manganese phosphate salt film with certain lubricity and heat resistance during friction, it effectively reduces the deformation and tearing of the friction surface material, thereby improving the friction-reducing and wear-resistant properties of ultra-high molecular weight polyethylene. The UHMWPE composite material prepared in this invention exhibits superior friction-reducing and wear-resistant properties under dry friction conditions when the content is within the range of 5-10 wt.% copper phosphate nanoparticle powder and 90-95 wt.% UHMWPE raw material powder.

[0046] The above embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Although the invention has been described in detail with reference to the embodiments, those skilled in the art should understand that various combinations, modifications, or equivalent substitutions of the technical solutions of the invention do not depart from the spirit and scope of the invention and should be covered within the scope of the claims of the invention.

Claims

1. A friction-reducing and wear-resistant composite material of UHMWPE modified with manganese trihydrate phosphate nanosheets, characterized in that: Composed of ultra-high molecular weight polyethylene (UHMWPE) and manganese trihydrate, wherein the manganese trihydrate has a nanosheet structure; both UHMWPE and manganese trihydrate nanosheets are in powder form. The manganese trihydrate nanosheets are first prepared, and then the UHMWPE powder and manganese trihydrate nanosheet powder are mechanically mixed and cured by hot pressing to form a friction-reducing and wear-resistant polymer material for engineering equipment; the content of manganese trihydrate nanosheets in the UHMWPE friction-reducing and wear-resistant composite material is 5~10 wt.%.

2. A method for preparing the UHMWPE friction-reducing and wear-resistant composite material according to claim 1, characterized in that, Includes the following steps: Step 1: Prepare manganese phosphate trihydrate nanosheets; Step 2: Select ultra-high molecular weight polyethylene powder; select manganese phosphate trihydrate nanosheet powder; Step 3: Mix the ultra-high molecular weight polyethylene powder and manganese phosphate trihydrate nanosheet powder obtained in Step 2 evenly to form a mixed powder; Step 4: Place the mixed powder in the mold, use a hot press to pre-press, then solidify and shape, and finally cool and demold.

3. The preparation method of the UHMWPE friction-reducing and wear-resistant composite material as described in claim 2, characterized in that: Before being hot-pressed in a mold, the mixed powder is dried in a drying oven at 66°C.

4. The preparation method of the UHMWPE friction-reducing and wear-resistant composite material as described in claim 2, characterized in that: In step 4, the pre-compression pressure is 20~30MPa; pre-compression is performed 2~5 times, each time for 3~5 minutes.

5. The preparation method of the UHMWPE friction-reducing and wear-resistant composite material as described in claim 4, characterized in that: In step 4, the temperature of the mold for curing is set at 160~180℃, and the curing time is 2~3 hours.

6. The method for preparing the UHMWPE friction-reducing and wear-resistant composite material as described in claim 5, characterized in that: In step 4, during the curing process, after holding the mold at a constant temperature for 2-3 hours, the heating of the mold is stopped, and the mold is placed in the air to cool naturally. During the cooling process, the pressure of the hot press is gradually increased according to the decrease in the mold temperature until the hot pressing pressure is 120-150 MPa. When the mold cools naturally to room temperature, the pressure is released and the mold is demolded to obtain the UHMWPE friction-reducing and wear-resistant composite material.

7. The method for preparing the UHMWPE friction-reducing and wear-resistant composite material as described in claim 6, characterized in that: The pressure parameters applied by the hot press during the cooling process in step 4 are as follows: when the temperature controller displays 108~112℃, apply a pressure of 10~20MPa to maintain the pressure; when the temperature is cooled to 98~102℃, apply a pressure of 30~40MPa to maintain the pressure; when the temperature is cooled to 88~92℃, apply a pressure of 70~80MPa to maintain the pressure; when the temperature is cooled to 78~82℃, apply a pressure of 120~150MPa to maintain the pressure until the temperature is cooled to room temperature.

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