CN116874960A

CN116874960A - Polymer material capable of improving wear resistance and service life, preparation method thereof and application thereof in three-layer composite material

Info

Publication number: CN116874960A
Application number: CN202310965939.0A
Authority: CN
Inventors: 请求不公布姓名
Original assignee: Jiangsu Ccvi Bearing Co ltd
Current assignee: Jiangsu Ccvi Bearing Co ltd
Priority date: 2023-08-02
Filing date: 2023-08-02
Publication date: 2023-10-13

Abstract

The invention provides a polymer material capable of improving wear resistance and service life, a preparation method thereof and application thereof in a three-layer composite material. The polymer material comprises the following components in percentage by mass: polyimide 10-20%; 3-5% of graphene oxide; 5-15% of aramid fiber; 1-3% of nano silicon carbide; and polytetrafluoroethylene balance. The polymer material is used for preparing spreadable soft bodies, the spreadable soft bodies are embedded and covered on copper powder plates with certain porosity, the prepared metal plastic three-layer composite material has good antifriction and wear resistance, and a sliding unit product prepared from the metal plastic three-layer composite material has good friction and wear resistance under high-frequency and dry friction conditions and has longer service life.

Description

Polymer material capable of improving wear resistance and service life, preparation method thereof and application thereof in three-layer composite material

Technical Field

The invention relates to the technical field of self-lubricating materials, in particular to a polymer material capable of improving wear resistance and service life, a preparation method thereof and application thereof in a three-layer composite material, and especially relates to a polymer material capable of improving wear resistance and service life and a three-layer composite material prepared from the polymer material and having high wear resistance and long service life under high-frequency and dry friction working conditions.

Background

The three-layer composite material takes modified polymer as a surface antifriction layer, adopts a carbon steel plate matrix, and is prepared into the three-layer composite material with good antifriction property and proper strength by a multi-layer composite process. The three-layer composite material is endowed with sufficient strength, bearing capacity and rigidity through the metal matrix; the middle spherical bronze powder sintered layer forms a pore skeleton, and the plastic antifriction layer material is firmly embedded into the copper powder gaps under the action of rolling force, so that the three-layer composite material with excellent comprehensive performance is obtained. Typically, the surface of the three-layer composite is covered with a very thin layer of antifriction plastic, typically less than 0.1mm thick. The three-layer composite material is widely applied to sliding support products, and the abrasion process is that a plastic layer polymer can form a highly oriented transfer film on the dual-view surface, the transfer film is continuously discharged in the operation process, the plastic layer is continuously abraded, the hard particles of copper powder particles exposing the middle sintering layer bear load, and the lubrication performance of the three-layer composite material is weakened along with the increasing number of copper powder particles exposing the surface until the copper powder particles cannot meet the use requirement and fail. Therefore, the mechanical strength, antifriction and wear resistance of the plastic layer, the thickness of the plastic layer and the like greatly influence the performance and the service life of the three-layer composite material.

Disclosure of Invention

Aiming at the defects of the prior art, the application provides a polymer material capable of improving wear resistance and service life, a preparation method thereof and application thereof in a three-layer composite material. In particular, a polymer material capable of improving wear resistance and service life is provided, and the polymer material is used for preparing spreadable soft bodies, is embedded and covered on copper powder plates with certain porosity, and is prepared into a metal plastic three-layer composite material. The polymer composite material layer of the metal plastic three-layer composite material prepared by the application has the thickness of 0.1-0.2 mm, has good antifriction and wear resistance, and the sliding unit product prepared by the metal plastic three-layer composite material has good friction and wear resistance under the conditions of high frequency and dry friction and has longer service life.

The application aims at realizing the following technical scheme:

in a first aspect, the present application provides a polymeric material having improved wear resistance and service life, comprising the following components in mass percent:

polyimide 10-20%;

3-5% of graphene oxide;

5-15% of aramid fiber;

1-3% of nano silicon carbide;

And polytetrafluoroethylene balance.

Preferably, the polytetrafluoroethylene is a mixture of polytetrafluoroethylene dispersion and polytetrafluoroethylene suspension powder;

the mass ratio of the polytetrafluoroethylene dispersion to the polytetrafluoroethylene suspension powder is 4:1 based on the polytetrafluoroethylene solid content;

the grain diameter of the polytetrafluoroethylene is 80-120 mu m.

Preferably, the average particle diameter of the polyphenyl ester is 9-18 μm.

Preferably, the polyimide is a polyimide modified with perfluorooctanoic acid;

the aramid fiber is prepared by removing surface impurities through surface treatment;

the graphene oxide is modified by amination;

the nano silicon carbide is nano silicon carbide surface-modified by a silane coupling agent.

Preferably, the preparation steps of the polyimide modified by perfluoro caprylic acid are as follows:

adding polyimide into ethylenediamine methanol solution, stirring at normal temperature for reaction for 5-7 h, and enabling the polyimide to be subjected to ring opening activation; and then adding the activated polyimide into a perfluoro octoic acid methanol solution, and stirring at room temperature for reaction for 10-14 h to obtain the perfluoro octoic acid modified polyimide.

Preferably, the preparation method of the aramid fiber powder with surface impurities removed by surface treatment comprises the following steps:

Adding aramid fiber into acetone, soaking for 10-14 h, and performing suction filtration; and then boiling for 0.5-2 h by using absolute ethyl alcohol, filtering, cleaning and drying.

Preferably, the preparation steps of the amination modified graphene oxide are as follows:

dispersing graphene oxide in deionized water by ultrasonic, adding tetraethylenepentamine, adjusting the pH value to 9-10, magnetically stirring the obtained dispersion liquid at room temperature for 15-25 min, transferring the obtained dispersion liquid into a hydrothermal reaction kettle, and stirring and reacting at 170-200 ℃ for 8-12 h to obtain the amination modified graphene oxide.

Preferably, the preparation method of the nano silicon carbide powder surface-modified by the silane coupling agent comprises the following steps:

adding the nano silicon carbide into an ethanol solution of the silane coupling agent, and magnetically stirring for 40-50 min to obtain the nano silicon carbide surface-modified by the silane coupling agent.

In a second aspect, the present invention provides a method for preparing a polymeric material having improved wear resistance and lifetime according to the foregoing, comprising the steps of:

step A1: weighing the raw materials according to a proportion;

step A2: adding graphene oxide and nano silicon carbide into polytetrafluoroethylene dispersion, and uniformly stirring;

step A3: mixing aramid fiber, polyimide and polytetrafluoroethylene suspension powder, and uniformly stirring;

Step A4: and (3) adding the mixed dry powder obtained in the step (A3) into the mixed material obtained in the step (A2), stirring uniformly, adding a solvent, and stirring and flocculating to obtain the spreadable soft body of the polymer material.

In a third aspect, the present invention provides a three-layer composite material having high wear resistance and long service life under high frequency, dry friction conditions, comprising a metal substrate, a porous copper powder layer, and a polymer material layer; the porous copper powder layer is arranged on the surface of the metal substrate layer, and the polymer material layer is arranged on the surface of the porous copper powder layer and in the pores;

the polymer material layer is prepared from the polymer material capable of improving the wear resistance and the service life or the polymer material capable of improving the wear resistance and the service life prepared by the method.

Preferably, the metal substrate is any one of a low-carbon steel plate, a high-strength steel plate and a copper plate; the thickness of the metal substrate is 0.5-2.5 mm.

Preferably, the copper powder adopted by the porous copper powder layer is copper alloy powder, and the particle size is 80-120 meshes.

Preferably, the thickness of the porous copper powder layer is 0.25-0.5 mm, and the porosity is 35-50%.

Preferably, the thickness of the polymer material layer is 0.10-0.20 mm.

Preferably, the preparation method of the three-layer composite material with high wear resistance and long service life under the high-frequency dry friction working condition comprises the following steps:

step B1: sintering copper powder particles on a metal substrate in a protective atmosphere to form a porous copper powder layer;

step B2: spreading and rolling spreadable soft body of polymer material prepared by the method of claim 8 on the sintered porous copper powder layer, and then drying until the organic solvent is completely volatilized;

step B3: rough rolling is carried out on the dried composite board, and then sintering is carried out;

step B4: and rolling the sintered composite board to the thickness required by the finished composite board, thus obtaining the three-layer composite self-lubricating material with high surface smoothness and low starting friction coefficient.

Preferably, in the step B1, the protective atmosphere is a mixed gas of nitrogen and hydrogen; the sintering temperature is 850-930 ℃, and the sintering time is 10-30 min.

Preferably, in the step B2, the drying temperature is 180-250 ℃ and the drying time is 30-60 min.

Preferably, in the step B3, the rolling amount of the rough rolling is 0.01 to 0.10mm.

Preferably, in the step B3, the sintering temperature is 350-395 ℃, the sintering time is 30-60 minutes, and the purity of nitrogen is more than 99.9%.

Compared with the prior art, the application has the following beneficial effects:

in the aspect of antifriction and wear-resistant polymer composite material, the application combines the performance advantages of each component material, improves the compatibility and interaction among each component by modifying the component filler, realizes the synergistic effect of each component of the polymer composite material, improves the strength, antifriction and wear resistance of the polymer composite material, and prepares a polymer material with high strength, small compression deformation and high antifriction and wear resistance. The polymer material is embedded into and covered on the surface of the copper powder plate, so that the metal plastic three-layer composite material with high polymer material layer thickness, small compression deformation and good antifriction and wear resistance is prepared, and the metal plastic three-layer composite material can be used for preparing sliding bearing products, and has good antifriction and wear resistance and long service life under the working conditions of high frequency and dry friction. The positive benefits and innovation points of the components are as follows:

firstly, the polytetrafluoroethylene material used in the application is polytetrafluoroethylene dispersion liquid and polytetrafluoroethylene suspension powder composition, the polytetrafluoroethylene suspension powder is suitable for compression molding process, the polymer composite material layer thickness of the metal plastic three-layer composite material prepared in the application is higher, and the mechanical property of the three-layer composite material prepared by the polytetrafluoroethylene suspension powder is better.

Second, the application adds polyimide to improve the comprehensive performance of the polymer composite material. The polyimide has higher strength, rigidity and heat resistance, the polyimide is modified by adopting ethylenediamine to carry out ring opening activation and then adopting perfluoro caprylic acid to carry out grafting modification, and the problem of poor compatibility of the polyimide and polytetrafluoroethylene caused by large polarity difference is solved after the modification. In the sintering plasticizing process, the perfluorinated branched chain of the modified polyimide can be inserted between the molecular chain layers of polytetrafluoroethylene, so that the binding force of the polyimide and the polytetrafluoroethylene is improved, and meanwhile, the polyimide molecular chain and the aramid fiber are intertwined, so that the overall binding force of the composite material is improved, and the strength and the wear resistance of the composite material are improved.

Thirdly, the tetraethylenepentamine modified graphene oxide is added, the graphene oxide has good thermal conductivity, heat resistance, high strength, high modulus and lubricity, the amino modified graphene oxide has better dispersibility, amino groups can interact with amino functional groups on the molecular face of polyimide-based aramid fiber, the interaction among the components is improved, the strength and wear resistance of the polymer composite material are further improved, and meanwhile the thermal conductivity and heat resistance of the composite material are improved. In addition, the lamellar graphene oxide performs synergistic antifriction with polytetrafluoroethylene in the process of grinding the polymer composite material and the metal surface, and under the action of shearing force and friction heat, the chemical action can be formed between the graphene oxide and the opposite grinding surface, and the lamellar graphene oxide can be inserted between polytetrafluoroethylene molecular layers, so that the stability of the lubrication transfer film is improved.

Fourth, the application adds nanometer silicon carbide modified by silane coupling agent as wear-resistant and reinforcing and toughening filler. The nano silicon carbide modified by the silane coupling agent has good dispersibility in the polymer, and the strength and toughness of the polymer composite material are improved. The silicon carbide has the performances of high temperature resistance, wear resistance, high thermal conductivity coefficient and the like, and the addition of the nano silicon carbide can realize the effects of reinforcing and toughening the polymer composite material and improving the thermal conductivity, the heat resistance and the wear resistance.

Fifthly, the aramid fiber powder is added as the reinforcing antifriction filler, the aramid fiber has high strength, high modulus and high wear resistance, and the aramid fiber has certain flexibility and is not easy to be extruded to form abrasive particles under the working conditions of high-frequency swing and the like. According to the application, the surface treatment is carried out on the aramid fiber, so that the active points in the molecular chain of the aramid fiber are increased, the interaction between the aramid fiber and other components is improved, and a better enhanced antifriction effect is realized.

Sixth, in terms of preparation technology, modified graphene oxide and modified nano silicon carbide which are not subjected to drying treatment are directly dispersed in polytetrafluoroethylene dispersion, and due to the small particle size of the graphene oxide and the nano silicon carbide, agglomeration and agglomeration can occur after the modified graphene oxide and the nano silicon carbide are dried, and the particle morphology of the modified graphene oxide and the nano silicon carbide can be damaged by grinding. The modified and undried graphene oxide and nano silicon carbide are directly added into polytetrafluoroethylene dispersion liquid, so that the dispersion uniformity of the modified and undried graphene oxide and nano silicon carbide in the polymer composite material is improved, and meanwhile, the preparation process is simplified.

Drawings

Other features, objects and advantages of the present application will become more apparent upon reading of the detailed description of non-limiting embodiments, given with reference to the accompanying drawings in which:

FIG. 1 is a schematic structural diagram of a three-layer composite material with high wear resistance and long service life under high frequency, dry friction conditions prepared in an embodiment of the present application;

wherein: 1-a layer of polymeric material; 2-a porous copper powder layer; 3-metal substrate.

Detailed Description

Unless otherwise indicated, implied from the context, or common denominator in the art, all parts and percentages in the present application are based on weight and the test and characterization methods used are synchronized with the filing date of the present application. Where applicable, the disclosure of any patent, patent application, or publication referred to in this disclosure is incorporated herein by reference in its entirety, and the equivalent patents are incorporated herein by reference, especially with respect to the definitions of synthetic techniques, product and process designs, polymers, comonomers, initiators or catalysts, etc. in the art, as disclosed in these documents. If the definition of a particular term disclosed in the prior art is inconsistent with any definition provided in the present application, the definition of the term provided in the present application controls.

In the specific embodiment of the invention, as shown in fig. 1, the three-layer composite material with high wear resistance and long service life under the high-frequency and dry friction working condition provided by the invention is a schematic structural diagram, and the three-layer composite material comprises a metal substrate 3, a porous copper powder layer 2 sintered on one side surface of the metal plate 3, and a polymer material layer 1 embedded in pores of the porous copper powder and covered on the surface of the porous copper powder layer.

In one embodiment, the metal substrate 3 may be a low-carbon steel plate (such as 10 steel, 15 steel, 20 steel, etc.), a high-strength steel plate (such as 50Mn steel, 60Mn steel, 65Mn steel, etc.), or other metal plate (such as copper plate), and the thickness of the metal substrate is 0.5-2.5 mm.

In a specific embodiment, the porous copper powder layer 2 sintered on one side surface of the metal substrate 3 is formed by sintering copper powder particles on the surface of the metal substrate 3; the copper powder particles are copper alloy powder particles, and the copper alloy is copper-tin alloy or other alloys; the particle diameter of the copper powder particles is 80-120 meshes, the thickness of the porous copper powder layer 2 is 0.3-0.5 mm, and the porosity is 35-50%.

In one embodiment, the polymeric material layer is made of a polymeric material that improves wear resistance and service life. The polymer material capable of improving the wear resistance and the service life comprises the following components in percentage by mass:

10-20% of polyimide, 3-5% of graphene oxide, 5-15% of aramid fiber, 1-3% of nano silicon carbide and the balance of polytetrafluoroethylene. The thickness of the polymer material layer is 0.1-0.2 mm.

Further, the polymer material comprises the following components in percentage by mass: polyimide 10-15%, graphene oxide 4%, aramid fiber 10-15%, nano silicon carbide 2% and polytetrafluoroethylene the rest.

Further, the mass ratio of the polytetrafluoroethylene dispersion to the polytetrafluoroethylene suspension powder is 4:1 based on the polytetrafluoroethylene solid content. The grain diameter of the polytetrafluoroethylene is 80-120 mu m. The polytetrafluoroethylene has a lower friction coefficient, and can form a lubrication transfer film on the grinding surface, so that the lubricity of the composite material is improved.

Further, the polyimide is a polyimide modified with perfluorooctanoic acid. The modified polyimide has a polar macromolecular chain and a nonpolar branched chain, the nonpolar perfluorinated branched chain can be inserted between polytetrafluoroethylene molecular layers, the polar macromolecular chain can be used with amino modified graphene oxide, surface treated aramid fiber and silane coupling agent modified nano silicon carbide interbody, an organic network skeleton is formed in the sintering and plasticizing process, the overall binding force of the composite material is improved, and the strength, the wear resistance and the like of the composite material are improved.

Further, the aramid fiber is an aramid fiber with surface impurities removed through surface treatment, and has high strength, high modulus and high wear resistance, so that the strength and wear resistance of the composite material are improved.

Further, the graphene oxide is an amination modified graphene oxide, and has high thermal conductivity, heat resistance, high strength and excellent lubricity. The graphene oxide modified by the machine has better dispersibility and binding force, and the addition of the graphene oxide further improves the strength, the thermal conductivity and the lubricity of the composite material.

Furthermore, the nano silicon carbide is nano silicon carbide modified by the surface of the silane coupling agent, the nano silicon carbide modified by the silane coupling agent has good dispersibility, the nano silicon carbide can play a role in reinforcing and toughening at the same time, and in addition, the nano silicon carbide has high thermal conductivity and high wear resistance, and the thermal conductivity and wear resistance of the composite material can be further improved.

In a specific embodiment, the invention also provides a preparation method of the three-layer composite material with high wear resistance and long service life under the high-frequency and dry friction working conditions, which comprises the following steps:

Step S1: adding a certain amount of polyimide into an ethylenediamine methanol solution with the mass fraction of 8-15%, stirring at normal temperature for reaction for 5-7 hours, carrying out ring opening activation on polyimide, carrying out suction filtration, washing with deionized water for multiple times, and then putting into a blast drying box for drying at 55-65 ℃ for 10-15 hours for later use. Adding the activated polyimide into 3-8% of perfluoro octoic acid methanol solution, stirring at room temperature for reaction for 10-14 h, performing suction filtration, cleaning with methanol for three times, cleaning with deionized water for multiple times, and drying in a blast drying oven at 55-65 ℃ for 10-15 h for later use.

Step S2: dispersing a certain amount of graphene oxide in deionized water by ultrasonic, adding tetraethylenepentamine according to the mass ratio of graphene oxide to tetraethylenepentamine of 1:8-12, dropwise adding ammonia water to adjust the pH value of the solution to 9-10, magnetically stirring the dispersion liquid at room temperature for 15-25 min, transferring the dispersion liquid into a hydrothermal reaction kettle, stirring at 170-200 ℃ for reacting for 8-12 h, cooling the solution after the reaction is finished, carrying out suction filtration, and washing with ethanol and deionized water for 5 times respectively for later use.

Step S3: adding a certain amount of aramid fiber into acetone, soaking for 10-14 h, filtering, boiling with absolute ethyl alcohol for 0.5-2h, filtering, washing with deionized water for three times, and drying in a vacuum drying oven at 70-90 ℃ for 5-7 h for standby.

Step S4: adding a certain amount of nano silicon carbide into an ethanol solution of KH550 silane coupling agent with the content of 0.5-2%, stirring for 40-50 min in a magnetic stirrer, performing suction filtration, washing with absolute ethanol for three times, washing with deionized water for three times, and performing suction filtration for later use.

Step S5: and (3) weighing polytetrafluoroethylene dispersion according to a proportion, and adding the graphene oxide treated in the step (S2) and the nano silicon carbide treated in the step (S4) into the polytetrafluoroethylene dispersion, and uniformly stirring.

Step S6: and (3) weighing the aramid fiber treated in the step (S3), the polyimide and polytetrafluoroethylene suspension powder treated in the step (S1) according to a proportion, adding the mixture into a high-speed stirrer, stirring for 1min, suspending for 1min, and repeatedly stirring for 3-5 times until the materials are uniformly dispersed.

Step S7: and (3) adding the dry powder uniformly mixed in the step (S6) into the polytetrafluoroethylene dispersion uniformly stirred in the step (S5), uniformly stirring in a high-speed stirrer, and then adding an organic solvent for stirring and flocculating to obtain the spreadable soft body with moderate hardness.

Step S8: sintering copper powder particles on a metal substrate, and obtaining the metal substrate containing the porous copper powder layer under the protection atmosphere of nitrogen and hydrogen, wherein the sintering temperature is 850-930 ℃ and the sintering time is 10-30 min;

Step S9: spreading and rolling the prepared spreadable soft body on the metal substrate containing the porous copper powder layer to obtain a metal plate containing a polymer composite material layer, wherein the thickness of the polymer composite material layer is 0.15-0.25 mm;

step S10: the metal plate containing the polymer composite material layer is dried for 30 to 60 minutes at 180 to 250 ℃ by adopting a drying furnace, and the solvent in the mixture is completely dried;

step S11: rough rolling is carried out on the composite board, the rolling amount is 0.01-0.10 mm, the composite material is rolled into the pores of the copper powder layer, the pores of the composite material layer are removed, and the compactness of the composite material is improved.

Step S12: sintering in a nitrogen protection sintering furnace at 350-395 deg.c for 30-60 min with nitrogen purity over 99.9%;

step S13: and rolling the sintered and plasticized plate to the thickness requirement of the finished plate, and removing the pores of the plastic layer to obtain the metal plastic three-layer composite material.

Examples

The technical scheme of the present application will be clearly and completely described in the following in connection with the embodiments of the present application. The reagents and starting materials used were purchased commercially, unless otherwise indicated. The experimental methods, in which specific conditions are not noted in the following examples, were selected according to conventional methods and conditions, or according to the commercial specifications.

In the following examples and comparative examples, specific information on raw materials used is as follows:

polytetrafluoroethylene suspension powder is purchased from the chemical industry Co., ltd, and the model is DF-17.

Polytetrafluoroethylene dispersion was purchased from eastern mountain chemical Co., ltd, model DF-306.

Polyimide is purchased from the new materials application technology Co.Ltd, west Kabushiki Kaisha, model 3835-UMP.

Aramid fiber powder was purchased from Jiangsu ai Alda composite Co.

Graphene oxide was purchased from beijing co island gold technologies limited.

Nano silicon carbide is purchased from Beijing De island gold technology Co., ltd, model DK-SiC-001.

The metal plate adopted by the metal basal layer is an SPCC low-carbon steel plate, and the thickness of the steel plate is 1.0mm.

The copper powder particles adopted by the porous copper powder layer are copper-tin alloy powder particles, the model of the copper-tin alloy is CuSn10, and the particle size of the powder is 80-120 meshes.

Comparative example 1

The comparative example provides a three-layer composite material with high wear resistance and long service life under the working conditions of high frequency and dry friction, which comprises a metal substrate, a porous copper powder layer and a polymer material layer; the porous copper powder layer is arranged on the surface of the metal substrate layer, and the polymer material layer is arranged on the surface of the porous copper powder layer and in the pores. The polymer material layer comprises the following components in percentage by mass: 15% of polyimide, 4% of amination modified graphene oxide, 10% of aramid fiber with surface impurities removed through surface treatment, 2% of silane coupling agent surface modified nano silicon carbide and 69% of polytetrafluoroethylene (polytetrafluoroethylene dispersion and polytetrafluoroethylene suspension powder are prepared according to the solid content ratio of polytetrafluoroethylene of 4:1).

A method of preparing a three-layer composite material having high wear resistance and long service life under high frequency, dry friction conditions, the method comprising the steps of:

step S1: dispersing a certain amount of graphene oxide in deionized water by ultrasonic, adding tetraethylenepentamine according to the mass ratio of graphene oxide to tetraethylenepentamine of 1:10, dropwise adding ammonia water to adjust the pH value of the solution to 9-10, magnetically stirring the dispersion liquid at room temperature for 20min, transferring the dispersion liquid into a hydrothermal reaction kettle, stirring and reacting at 180 ℃ for 10h, cooling the solution after the reaction is completed, carrying out suction filtration, washing with ethanol and deionized water for 5 times, and obtaining the amination modified graphene oxide for standby.

Step S2: adding a certain amount of aramid fiber into acetone, soaking for 12 hours, carrying out suction filtration, boiling with absolute ethyl alcohol for 1 hour, carrying out suction filtration, washing with deionized water for three times, and drying in a vacuum drying oven at 80 ℃ for 6 hours to obtain the aramid fiber with surface impurities removed through surface treatment for standby.

Step S3: adding a certain amount of nano silicon carbide into ethanol solution of KH550 silane coupling agent with content of 1%, stirring for 45min in a magnetic stirrer, performing suction filtration, washing with absolute ethanol for three times, washing with deionized water for three times, and performing suction filtration to obtain nano silicon carbide with surface modified silane coupling agent for later use.

Step S4: and weighing polytetrafluoroethylene dispersion liquid according to a proportion, adding the amination modified graphene oxide and silane coupling agent surface modified nano silicon carbide into the polytetrafluoroethylene dispersion liquid, and uniformly stirring.

Step S5: the aramid fiber, polyimide and polytetrafluoroethylene suspension powder with surface impurities removed by surface treatment are weighed according to a proportion, added into a high-speed stirrer to be stirred for 1min, suspended for 1min, and repeatedly stirred for 3-5 times until the materials are uniformly dispersed.

Step S6: and (3) adding the uniformly mixed dry powder obtained in the step (S5) into the uniformly mixed polytetrafluoroethylene dispersion in the step (S4), uniformly stirring in a high-speed stirrer, and then adding an organic solvent (absolute ethyl alcohol) for stirring and flocculating to obtain the spreadable soft body of the polymer material with moderate hardness.

Step S7: and sintering the copper powder particles on the metal substrate, wherein the sintering temperature is 900 ℃ and the sintering time is 20min under the protection atmosphere of nitrogen and hydrogen, and obtaining the metal substrate containing copper powder.

Step S8: and (3) spreading and rolling the prepared spreadable soft body on the metal substrate containing the copper powder to obtain the metal plate containing the polymer composite material layer, wherein the thickness of the spreadable soft body layer is 0.2mm.

Step S9: and (3) drying the metal plate containing the polymer composite material layer by adopting a drying furnace at 200 ℃ for 45 minutes, wherein the solvent in the mixture is completely dried.

Step S10: rough rolling is carried out on the composite board, the rolling amount is 0.10mm, the composite material is rolled into copper powder pores, the pores of the composite material layer are removed, and the compactness of the composite material is improved.

Step S11: sintering in a nitrogen protection sintering furnace at 375 deg.c for 50 min with nitrogen purity over 99.9%.

Step S12: and rolling the sintered and plasticized plate to the thickness requirement of the finished plate, and removing the pores of the plastic layer to obtain the metal plastic three-layer composite material.

Comparative example 2

The comparative example provides a three-layer composite material with high wear resistance and long service life under the working conditions of high frequency and dry friction, which comprises a metal substrate, a porous copper powder layer and a polymer material layer; the porous copper powder layer is arranged on the surface of the metal substrate layer, and the polymer material layer is arranged on the surface of the porous copper powder layer and in the pores. The polymer material layer comprises the following components in percentage by mass: 15% of polyimide modified by perfluoro caprylic acid, 4% of graphene oxide, 10% of aramid fiber with surface impurities removed by surface treatment, 2% of nano silicon carbide surface-modified by a silane coupling agent, and 69% of polytetrafluoroethylene (polytetrafluoroethylene dispersion and polytetrafluoroethylene suspension powder are prepared according to a polytetrafluoroethylene solid content ratio of 4:1).

step S1: adding a certain amount of polyimide powder into an ethylenediamine methanol solution with the mass fraction of 10%, stirring at normal temperature for reaction for 6 hours, carrying out ring opening activation on polyimide, carrying out suction filtration, washing with deionized water for many times, and then putting into a blast drying oven for drying at 60 ℃ for 12 hours for later use. Adding the activated polyimide into a perfluoro octoic acid methanol solution with the mass fraction of 5%, stirring at room temperature for reaction for 12 hours, carrying out suction filtration, washing with methanol for three times, washing with deionized water for multiple times, and putting into a blast drying oven for drying at 60 ℃ for 12 hours to obtain the polyimide modified by perfluoro octoic acid for later use.

Step S2: adding a certain amount of aramid fiber into acetone, soaking for 12 hours, carrying out suction filtration, boiling with absolute ethyl alcohol for 1 hour, carrying out suction filtration, washing with deionized water three times, and drying in a vacuum drying oven at 80 ℃ for 6 hours to obtain the aramid fiber with surface impurities removed through surface treatment for standby.

Step S4: and weighing polytetrafluoroethylene dispersion liquid according to a proportion, adding graphene oxide and the nano silicon carbide subjected to surface modification by the silane coupling agent into the polytetrafluoroethylene dispersion liquid, and uniformly stirring.

Step S5: the aramid fiber, polyimide and polytetrafluoroethylene suspension powder which are subjected to surface treatment and surface impurity removal are weighed according to a proportion, added into a high-speed stirrer and stirred for 1min, suspended for 1min, and repeatedly stirred for 3-5 times until the materials are uniformly dispersed.

Comparative example 3

The comparative example provides a three-layer composite material with high wear resistance and long service life under the working conditions of high frequency and dry friction, which comprises a metal substrate, a porous copper powder layer and a polymer material layer; the porous copper powder layer is arranged on the surface of the metal substrate layer, and the polymer material layer is arranged on the surface of the porous copper powder layer and in the pores. The polymer material layer comprises the following components in percentage by mass: 15% of polyimide modified by perfluoro caprylic acid, 4% of oxidized graphene modified by amination, 10% of aramid fiber, 2% of nano silicon carbide modified by a silane coupling agent surface, and 69% of polytetrafluoroethylene (polytetrafluoroethylene dispersion and polytetrafluoroethylene suspension powder are prepared according to a polytetrafluoroethylene solid content ratio of 4:1).

Step S2: dispersing a certain amount of graphene oxide in deionized water by ultrasonic, adding tetraethylenepentamine according to the mass ratio of graphene oxide to tetraethylenepentamine of 1:10, dropwise adding ammonia water to adjust the pH value of the solution to 9-10, magnetically stirring the dispersion liquid at room temperature for 20min, transferring the dispersion liquid into a hydrothermal reaction kettle, stirring and reacting at 180 ℃ for 10h, cooling the solution after the reaction is completed, carrying out suction filtration, washing with ethanol and deionized water for 5 times, and obtaining the amination modified graphene oxide for standby.

Step S5: weighing aramid fiber, polyimide modified by perfluoro caprylic acid and polytetrafluoroethylene suspension powder according to a proportion, adding into a high-speed stirrer for stirring for 1min, suspending for 1min, and repeatedly stirring for 3-5 times until the materials are uniformly dispersed.

Comparative example 4

The comparative example provides a three-layer composite material with high wear resistance and long service life under the working conditions of high frequency and dry friction, which comprises a metal substrate, a porous copper powder layer and a polymer material layer; the porous copper powder layer is arranged on the surface of the metal substrate layer, and the polymer material layer is arranged on the surface of the porous copper powder layer and in the pores. The polymer material layer comprises the following components in percentage by mass: 15% of polyimide modified by perfluoro caprylic acid, 4% of oxidized graphene modified by amination, 10% of aramid fiber with surface impurities removed by surface treatment, and 71% of polytetrafluoroethylene (polytetrafluoroethylene dispersion and polytetrafluoroethylene suspension powder are prepared according to the solid content ratio of polytetrafluoroethylene of 4:1).

Step S3: adding a certain amount of aramid fiber into acetone, soaking for 12 hours, carrying out suction filtration, boiling with absolute ethyl alcohol for 1 hour, carrying out suction filtration, washing with deionized water three times, and drying in a vacuum drying oven at 80 ℃ for 6 hours to obtain the aramid fiber with surface impurities removed through surface treatment for standby.

Step S4: and weighing polytetrafluoroethylene dispersion according to a proportion, adding the amination modified graphene oxide into the polytetrafluoroethylene dispersion, and uniformly stirring.

Comparative example 5

The comparative example provides a three-layer composite material with high wear resistance and long service life under the working conditions of high frequency and dry friction, which comprises a metal substrate, a porous copper powder layer and a polymer material layer; the porous copper powder layer is arranged on the surface of the metal substrate layer, and the polymer material layer is arranged on the surface of the porous copper powder layer and in the pores. The polymer material layer comprises the following components in percentage by mass: 15% of polyimide modified by perfluoro caprylic acid, 8% of oxidized graphene modified by amination, 10% of aramid fiber with surface impurities removed by surface treatment, 2% of nano silicon carbide modified by a silane coupling agent surface, and 65% of polytetrafluoroethylene (polytetrafluoroethylene dispersion and polytetrafluoroethylene suspension powder are prepared according to the solid content ratio of polytetrafluoroethylene of 4:1).

Step S4: adding a certain amount of nano silicon carbide into ethanol solution of KH550 silane coupling agent with content of 1%, stirring for 45min in a magnetic stirrer, performing suction filtration, washing with absolute ethanol for three times, washing with deionized water for three times, and performing suction filtration to obtain nano silicon carbide with surface modified silane coupling agent for later use.

Step S5: and weighing polytetrafluoroethylene dispersion liquid according to a proportion, adding the amination modified graphene oxide and silane coupling agent surface modified nano silicon carbide into the polytetrafluoroethylene dispersion liquid, and uniformly stirring.

Step S6: the aramid fiber, polyimide and polytetrafluoroethylene suspension powder which are subjected to surface treatment and surface impurity removal are weighed according to a proportion, added into a high-speed stirrer and stirred for 1min, suspended for 1min, and repeatedly stirred for 3-5 times until the materials are uniformly dispersed.

Step S7: and (3) adding the uniformly mixed dry powder obtained in the step (S5) into the uniformly mixed polytetrafluoroethylene dispersion in the step (S4), uniformly stirring in a high-speed stirrer, and then adding an organic solvent (absolute ethyl alcohol) for stirring and flocculating to obtain the spreadable soft body of the polymer material with moderate hardness.

Step S8: and sintering the copper powder particles on the metal substrate, wherein the sintering temperature is 900 ℃ and the sintering time is 20min under the protection atmosphere of nitrogen and hydrogen, and obtaining the metal substrate containing copper powder.

Step S9: and (3) spreading and rolling the prepared spreadable soft body on the metal substrate containing the copper powder to obtain the metal plate containing the polymer composite material layer, wherein the thickness of the spreadable soft body layer is 0.2mm.

Step S10: and (3) drying the metal plate containing the polymer composite material layer by adopting a drying furnace at 200 ℃ for 45 minutes, wherein the solvent in the mixture is completely dried.

Step S11: rough rolling is carried out on the composite board, the rolling amount is 0.10mm, the composite material is rolled into copper powder pores, the pores of the composite material layer are removed, and the compactness of the composite material is improved.

Step S12: sintering in a nitrogen protection sintering furnace at 375 deg.c for 50 min with nitrogen purity over 99.9%.

Comparative example 6

The comparative example provides a three-layer composite material with high wear resistance and long service life under the working conditions of high frequency and dry friction, which comprises a metal substrate, a porous copper powder layer and a polymer material layer; the porous copper powder layer is arranged on the surface of the metal substrate layer, and the polymer material layer is arranged on the surface of the porous copper powder layer and in the pores. The polymer material layer comprises the following components in percentage by mass: 25% of polyimide modified by perfluoro caprylic acid, 4% of oxidized graphene modified by amination, 10% of aramid fiber with surface impurities removed by surface treatment, 2% of nano silicon carbide modified by a silane coupling agent surface, and 59% of polytetrafluoroethylene (polytetrafluoroethylene dispersion and polytetrafluoroethylene suspension powder are prepared according to the solid content ratio of polytetrafluoroethylene of 4:1).

Comparative example 7

The comparative example provides a three-layer composite material with high wear resistance and long service life under the working conditions of high frequency and dry friction, which comprises a metal substrate, a porous copper powder layer and a polymer material layer; the porous copper powder layer is arranged on the surface of the metal substrate layer, and the polymer material layer is arranged on the surface of the porous copper powder layer and in the pores. The polymer material layer comprises the following components in percentage by mass: 15% of polyimide modified by perfluoro caprylic acid, 4% of oxidized graphene modified by amination, 3% of aramid fiber with surface impurities removed by surface treatment, 2% of nano silicon carbide modified by a silane coupling agent surface, and 76% of polytetrafluoroethylene (polytetrafluoroethylene dispersion and polytetrafluoroethylene suspension powder are prepared according to the solid content ratio of polytetrafluoroethylene of 4:1).

Comparative example 8

The comparative example provides a three-layer composite material with high wear resistance and long service life under the working conditions of high frequency and dry friction, which comprises a metal substrate, a porous copper powder layer and a polymer material layer; the porous copper powder layer is arranged on the surface of the metal substrate layer, and the polymer material layer is arranged on the surface of the porous copper powder layer and in the pores. The polymer material layer comprises the following components in percentage by mass: 15% of polyimide modified by perfluoro caprylic acid, 4% of oxidized graphene modified by amination, 10% of aramid fiber with surface impurities removed by surface treatment, 2% of nano silicon carbide and 69% of polytetrafluoroethylene (polytetrafluoroethylene dispersion and polytetrafluoroethylene suspension powder are prepared according to the solid content ratio of polytetrafluoroethylene of 4:1).

Step S4: and weighing polytetrafluoroethylene dispersion according to a proportion, adding the amination modified graphene oxide and nano silicon carbide into the polytetrafluoroethylene dispersion, and uniformly stirring.

Example 1

The embodiment provides a three-layer composite material with high wear resistance and long service life under the working conditions of high frequency and dry friction, which comprises a metal substrate, a porous copper powder layer and a polymer material layer; the porous copper powder layer is arranged on the surface of the metal substrate layer, and the polymer material layer is arranged on the surface of the porous copper powder layer and in the pores. The polymer material layer comprises the following components in percentage by mass: 15% of polyimide modified by perfluoro caprylic acid, 4% of oxidized graphene modified by amination, 10% of aramid fiber with surface impurities removed by surface treatment, 2% of nano silicon carbide modified by a silane coupling agent surface, and 69% of polytetrafluoroethylene (polytetrafluoroethylene dispersion and polytetrafluoroethylene suspension powder are prepared according to the solid content ratio of polytetrafluoroethylene of 4:1).

Example 2

The embodiment provides a three-layer composite material with high wear resistance and long service life under the working conditions of high frequency and dry friction, which comprises a metal substrate, a porous copper powder layer and a polymer material layer; the porous copper powder layer is arranged on the surface of the metal substrate layer, and the polymer material layer is arranged on the surface of the porous copper powder layer and in the pores. The polymer material layer comprises the following components in percentage by mass: 10% of polyimide modified by perfluoro caprylic acid, 4% of oxidized graphene modified by amination, 10% of aramid fiber with surface impurities removed by surface treatment, 2% of nano silicon carbide modified by a silane coupling agent surface, and 74% of polytetrafluoroethylene (polytetrafluoroethylene dispersion and polytetrafluoroethylene suspension powder are prepared according to the solid content ratio of polytetrafluoroethylene of 4:1).

Example 3

The embodiment provides a three-layer composite material with high wear resistance and long service life under the working conditions of high frequency and dry friction, which comprises a metal substrate, a porous copper powder layer and a polymer material layer; the porous copper powder layer is arranged on the surface of the metal substrate layer, and the polymer material layer is arranged on the surface of the porous copper powder layer and in the pores. The polymer material layer comprises the following components in percentage by mass: 15% of polyimide modified by perfluoro caprylic acid, 4% of oxidized graphene modified by amination, 15% of aramid fiber with surface impurities removed by surface treatment, 2% of nano silicon carbide modified by a silane coupling agent surface, and 64% of polytetrafluoroethylene (polytetrafluoroethylene dispersion and polytetrafluoroethylene suspension powder are prepared according to the solid content ratio of polytetrafluoroethylene of 4:1).

Performance testing

Sampling the three-layer composite material plates prepared in each comparative example and example, and respectively performing an end grinding test, wherein the model of an end grinding tester is as follows: MSU-1 end face friction wear testing machine, lubrication mode: dry friction, test conditions: test speed: 0.4m/s, test load: the initial 4MPa load is increased by 2MPa every 10 minutes until the load is constant after 20MPa is added, and the test time is 181 minutes. The test results are shown in Table 1.

Table 1 end mill test results for the composites of comparative examples 1-7 and examples 1-3

The three-layer composite plates prepared in each comparative example and example were respectively prepared into shaft sleeves of the same type for testing, including a swing endurance test and a static pressure test.

The swing test is carried out on a swing testing machine, the lubrication mode is dry friction, and the test conditions are as follows: the test load is 100MPa, the test speed is 0.04m/s, and the cycle number is 100000. The test results are shown in Table 2.

Table 2 results of the sway durability test of the composite materials of comparative examples 1 to 7 and examples 1 to 3

Material numbering	Average coefficient of friction	Wearing capacity (mm)
			Comparative example 1	0.045	0.085
Comparative example 2	0.043	0.077
			Comparative example 3	0.046	0.082
Comparative example 4	0.043	0.076
			Comparative example 5	0.044	0.074
Comparative example 6	0.058	0.086
			Comparative example 7	0.039	0.091
Comparative example 8	0.047	0.078
			Example 1	0.045	0.059
Example 2	0.040	0.062
			Example 3	0.048	0.056

The static pressure test is carried out on a microcomputer controlled electronic universal tester, and the test load is 300MPa. The test results are shown in Table 3.

TABLE 3 static pressure test results for the composite materials of comparative examples 1-7 and examples 1-3

Material numbering	Permanent set (mm)
		Comparative example 1	0.010
Comparative example 2	0.009
		Comparative example 3	0.010
Comparative example 4	0.014
		Comparative example 5	0.007
Comparative example 6	0.006
		Comparative example 7	0.014
Comparative example 8	0.009
		Example 1	0.008
Example 2	0.010
		Example 3	0.007

The test results of the composite material performance are analyzed, and the test results of comparative example 1 and example 1 show that the average friction coefficient is not greatly different and the maximum abrasion amount is obviously larger in the end grinding test results of the composite material compared with the addition of the polyimide modified by perfluoro caprylic acid. In the results of the swing durability test, the average friction coefficient of comparative example 1 was not much different from that of example 1, but the abrasion loss was significantly higher than that of example 1. In the static pressure test results, the permanent set of comparative example 1 was slightly lower than that of example 1. The above results are that the bonding force of the composite material is poor due to poor compatibility of unmodified polyimide and polytetrafluoroethylene, and thus the strength and the wear resistance are low.

As can be seen from the test results of comparative example 2 and example 1, the average friction coefficient is not different in the end mill test results of the composite material in which unmodified graphene oxide is added compared with the aminated modified graphene oxide, but the maximum abrasion amount of the composite material of comparative example 2 is significantly larger. In the results of the swing durability test, the average friction coefficient of comparative example 2 was not much different from that of example 1, but the abrasion loss was significantly higher than that of example 1. In the static pressure test results, the permanent set of comparative example 2 was slightly larger. The above results are due to poor dispersibility of graphene oxide in the composite material.

As can be seen from the test results of comparative example 3 and example 1, the average friction coefficient is not greatly different in the end mill test results of the composite material in which the aramid fiber having not been surface-treated is added, as compared with the aramid fiber having been surface-treated, but the maximum abrasion amount of the composite material of comparative example 3 is significantly increased. In the results of the swing endurance test, the average friction coefficients of the two were not greatly different, but the abrasion loss was significantly higher than that of example 1. In the static pressure test results, the permanent deformation amounts of the two are not greatly different. The above results are due to poor bonding force of the unmodified aramid fiber to other component materials.

As can be seen from the test results of comparative example 4 and example 1, in the end mill test results of the composite material, the average friction coefficient of comparative example 4 and example 1 is not greatly different from that of the composite material, but the maximum abrasion amount of comparative example 4 is significantly higher than that of example 1. In the results of the swing endurance test, the average friction coefficients of the two were not greatly different, but the abrasion loss was significantly higher than that of example 1. In the static pressure test results, the permanent set of example 1 was significantly lower than that of comparative example 4. The result is that the nano silicon carbide can be added to play a role in strengthening and toughening, and simultaneously improve the wear resistance of the composite material and reduce the permanent deformation.

As can be seen from the test results of comparative example 5 and example 1, in the end mill test results, the addition of excessive amination-modified graphene oxide slightly reduced the average friction coefficient of the composite material, but the maximum abrasion amount of the composite material was significantly increased. In the results of the swing endurance test, the average friction coefficients of the two were not greatly different, but the abrasion loss was significantly higher than that of example 1. In the static pressure test results, the permanent deformation amounts of the two are not greatly different. The above results are due to poor bonding of the composite material caused by the addition of excessive oxidized graphene.

As can be seen from the test results of comparative example 6 and example 1, in the end mill test results, the average friction coefficient and the maximum abrasion amount of comparative example 6 are significantly larger than those of example 1. In the results of the swing durability test, the average friction coefficient and the wear amount of comparative example 6 were also significantly higher than those of example 1. In the static pressure test results, the permanent deformation amounts of the two are not greatly different. The above results are due to the relatively high coefficient of friction of polyimide.

As can be seen from the test results of comparative example 7 and example 1, the addition of too little surface-modified aramid fiber in the end mill test results reduced the average friction coefficient of the composite material, but increased the maximum abrasion amount significantly. In the results of the swing durability test, the average friction coefficient of comparative example 7 was lowered, but the abrasion loss was also significantly higher than that of example 1. In the static pressure test results, the permanent set of example 1 was significantly lower than that of comparative example 7. This is due to the reduced amount of aramid fiber added, resulting in reduced strength and abrasion resistance of the composite.

As can be seen from the test results of comparative example 8 and example 1, the difference in friction coefficient between comparative example 8 and example 1 was not large, but the maximum abrasion amount of the composite material of comparative example 8 was significantly larger than that of example 1. The difference in the amount of crowded deformation between the two was also small in the static pressure test results. The increase in the abrasion loss of the composite material of comparative example 8 is caused by the self-agglomeration of the unmodified nano-silicon carbide and the uneven dispersion in the composite material.

As can be seen from the test results of comparative examples 1 to 3, the composite materials prepared according to the components and proportions of the present application have little difference in friction coefficient and abrasion loss.

The previous description of the embodiments is provided to facilitate a person of ordinary skill in the art in order to make and use the present application. It will be apparent to those skilled in the art that various modifications can be readily made to these embodiments and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present application is not limited to the above-described embodiments, and those skilled in the art, based on the present disclosure, should make improvements and modifications without departing from the scope of the present application.

Claims

1. A polymer material capable of improving wear resistance and service life, which is characterized by comprising the following components in percentage by mass:

polyimide 10-20%;

3-5% of graphene oxide;

5-15% of aramid fiber;

1-3% of nano silicon carbide;

and polytetrafluoroethylene balance.

2. The polymeric material of claim 1, wherein the polytetrafluoroethylene is a mixture of polytetrafluoroethylene dispersion and polytetrafluoroethylene suspension;

the grain diameter of the polytetrafluoroethylene is 80-120 mu m.

3. The polymer material of claim 1, wherein the polystyrene has an average particle size of 9 to 18 μm.

4. The polymer material with improved wear resistance and service life according to claim 1, wherein the polyimide is a polyimide modified with perfluorooctanoic acid;

the graphene oxide is modified by amination;

5. The polymer material with improved abrasion resistance and service life according to claim 4, wherein the preparation steps of the perfluoro octanoic acid modified polyimide are as follows:

6. The polymer material with improved abrasion resistance and service life according to claim 4, wherein the aramid fiber with surface impurities removed by surface treatment is prepared by the steps of:

7. The polymer material capable of improving wear resistance and service life according to claim 4, wherein the preparation steps of the amination modified graphene oxide are as follows:

8. The polymer material capable of improving wear resistance and service life according to claim 4, wherein the preparation steps of the silane coupling agent surface modified nano silicon carbide are as follows:

9. A method for preparing a polymeric material having improved wear resistance and service life according to any one of claims 1 to 8, comprising the steps of:

step A1: weighing the raw materials according to a proportion;

10. The three-layer composite material with high wear resistance and long service life under the high-frequency dry friction working condition is characterized by comprising a metal substrate, a porous copper powder layer and a polymer material layer; the porous copper powder layer is arranged on the surface of the metal substrate layer, and the polymer material layer is arranged on the surface of the porous copper powder layer and in the pores;

wherein the polymer material layer is prepared from the polymer material capable of improving the wear resistance and the service life or the polymer material capable of improving the wear resistance and the service life prepared by the method of claim 9;

The preparation method of the three-layer composite material with high wear resistance and long service life under the working conditions of high frequency and dry friction comprises the following steps:

step B4: and rolling the sintered composite board to the thickness required by the finished composite board, thus obtaining the three-layer composite material.