A thermoplastic polyimide composite material for piston ring, preparation method and piston ring

Abstract

The invention discloses a thermoplastic polyimide composite material for piston ring, a preparation method and a piston ring, which are composed of the following materials by mass percentage: thermoplastic polyimide 60-70; polyetheretherketone 10-20; modified carbon fiber 10-15; graphene oxide 5-10; chain extender 1-3; lubricant 1-2; antioxidant 0.5-1. The disadvantages of high wear rate, high linear expansion coefficient and inability to withstand high temperature of traditional piston rings are solved; the modification of carbon fiber reduces the probability of fiber shedding during the wear process, and reduces furrow wear and adhesive wear. The addition of graphene oxide further reduces the friction coefficient of the composite material, and a stable lubrication transfer film can be generated under long-term high load, solving many difficulties in the melt blending processing of thermoplastic polyimide high-temperature materials.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a thermoplastic polyimide composite material for a piston ring, a preparation method and a piston ring. Background Art

[0002] The piston ring of a lubricating compressor is one of the key components in the compressor, and its performance directly affects the efficiency and life of the compressor. The main functions of the piston ring include sealing, controlling oil flow, and preventing gas leakage. Its design and application are crucial to the performance and reliability of the compressor. In oil-free lubricated compressors, the material selection of the piston ring is particularly important, which directly affects the degree of wear and service life of the piston ring. The piston ring needs to be made of self-lubricating material to reduce friction and wear, thereby increasing service life and efficiency.

[0003] However, the working temperature of general engineering plastics is relatively low, generally below 120°C, and they cannot be used under the harsh working conditions of high temperature, high pressure and high wear resistance of piston rings. Applicable materials such as polytetrafluoroethylene, polyimide, polyetheretherketone, etc. all have their own shortcomings. Polyetheretherketone has good toughness and is easy to process but has poor long-term wear resistance. Polyimide has high strength and good wear resistance but is difficult to form. Polytetrafluoroethylene has good lubricity but is resistant to creep, and requires comprehensive modification to meet the use requirements. Summary of the invention

[0004] The first invention aims to overcome the deficiencies of the prior art, solve the shortcomings of the traditional piston rings, such as high wear rate, inability to withstand high temperatures, and high linear expansion coefficient, and provide a thermoplastic polyimide composite material that can be used for a long time under harsh working conditions.

[0005] The second invention of the present invention is to solve the many difficulties in the melt blending processing of thermoplastic polyimide high-temperature materials and provide a suitable processing technology.

[0006] To achieve the purpose of the present invention, the present invention adopts the following technical solutions:

[0007] A thermoplastic polyimide composite material for a piston ring consists of the following materials in percentage by mass: 60-70 parts of thermoplastic polyimide; 10-20 parts of polyetheretherketone; 10-15 parts of modified carbon fiber; 5-10 parts of graphene oxide; 1-3 parts of a chain extender; 1-2 parts of a lubricant; and 0.5-1 parts of an antioxidant.

[0008] In some embodiments, thermoplastic polyimide is purchased from Saudi Sabic, model: EXTEM XH1015; polyetheretherketone is purchased from Victrex, model: 450G; graphene oxide is purchased from Jiangsu Xianfeng Nanomaterial Technology Co., Ltd., model: XFSG01; the lubricant can be YY-703A from Guangzhou Yuantai New Materials Co., Ltd.; the chain extender can be SA-U980 from Quansheng Polycarbon Technology Co., Ltd.; the antioxidant can be Irganox 1098 from BASF; and the carbon fiber is T700 chopped carbon fiber from Toray Industries, Japan.

[0009] In some embodiments, 60 parts of thermoplastic polyimide, 20 parts of polyetheretherketone, 5 parts of graphene oxide, 10 parts of modified carbon fiber, 3 parts of chain extender, 1.5 parts of lubricant, and 0.5 parts of antioxidant;

[0010] Or, 70 parts of thermoplastic polyimide, 10 parts of polyetheretherketone, 5 parts of graphene oxide, 10 parts of modified carbon fiber, 3 parts of chain extender, 1 part of lubricant, and 1 part of antioxidant;

[0011] Or, 62.5 parts of thermoplastic polyimide, 15 parts of polyetheretherketone, 10 parts of graphene oxide, 10 parts of modified carbon fiber, 1 part of chain extender, 1 part of lubricant, and 0.5 part of antioxidant;

[0012] Or, 60 parts of thermoplastic polyimide, 12 parts of polyetheretherketone, 8 parts of graphene oxide, 15 parts of modified carbon fiber, 2.5 parts of chain extender, 2 parts of lubricant, and 0.5 parts of antioxidant;

[0013] Or, 60 parts of thermoplastic polyimide, 10 parts of polyetheretherketone, 7 parts of graphene oxide, 20 parts of modified carbon fiber, 1.5 parts of chain extender, 1 part of lubricant, and 0.5 part of antioxidant.

[0014] A method for preparing a thermoplastic polyimide composite material for a piston ring comprises the following steps:

[0015] S100: weighing various raw materials according to the formula, and drying the weighed thermoplastic polyimide and polyetheretherketone;

[0016] S200: mixing the thermoplastic polyimide, polyetheretherketone, antioxidant and chain extender dried in step S100 in a high-speed mixer for 5 minutes and then melt-extruding to form a TPI alloy material;

[0017] S300: The TPI alloy material in step S200 is mixed with other raw materials in a high-speed mixer for 10 minutes, and then melt-extruded to form a thermoplastic polyimide composite material.

[0018] In some embodiments, the drying process in step S100 is performed at a temperature of 160-170° C. and the drying time is 4-8 hours.

[0019] In some embodiments, the melt extrusion operations in step S200 and step S300 are carried out in an extruder, and the temperatures of each section in the extruder are: 320-350°C in zone 1, 350-370°C in zone 2, 370-380°C in zone 3, 380-390°C in zone 4, 380-390°C in zone 5, 380-390°C in zone 6, 380-390°C in zone 7, 380-390°C in zone 8, 370-380°C in zone 9, 370-380°C in zone 10, and 395-400°C in zone 11, wherein the screw aspect ratio is 36-48, and the screw speed is 200-500rpm.

[0020] In some embodiments, the modified carbon fiber is prepared by the following method:

[0021] Step 1: first oxidizing the carbon fiber with a mixed acid to obtain oxidized carbon fiber;

[0022] Step 2: reacting the oxidized carbon fiber with a silane coupling agent to prepare the modified carbon fiber, wherein the mixed acid is a mixture of concentrated sulfuric acid and concentrated nitric acid, and the volume ratio of the concentrated nitric acid to the concentrated sulfuric acid is 2-5:1.

[0023] In some embodiments, concentrated sulfuric acid is a sulfuric acid aqueous solution with a mass fraction greater than or equal to 70%; concentrated nitric acid is a nitric acid aqueous solution with a mass fraction greater than or equal to 60%; the mass ratio of the silane coupling agent to the oxidized carbon fiber is 1:200-800.

[0024] In some embodiments, in step one, the carbon fiber is first cleaned with acetone and ultrasonically dispersed. After 4-6 hours, it is rinsed with clean water 3-5 times and dried; the dried carbon fiber is then immersed in a mixed acid solution of concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 3:1, ultrasonically dispersed at 60-80°C, rinsed with distilled water 3-5 times after 30-120 minutes, and vacuum dried at 80-100°C; in step two, the treated carbon fiber is immersed in a solution of silane coupling agent KH550, ethanol and distilled water in a ratio of 20:72:8, ultrasonically dispersed, after 4-24 hours, rinsed with distilled water 3-5 times, and vacuum dried at 80-100°C to prepare modified carbon fiber for standby use.

[0025] A piston ring is made of a thermoplastic polyimide composite material for piston rings.

[0026] The thermoplastic polyimide composite material for a piston ring, a preparation method and a piston ring provided by the present invention have the following advantages:

[0027] The modified thermoplastic polyimide in the present invention is tightly combined with the polyetheretherketone resin, which not only retains the dimensional stability and wear resistance of the thermoplastic polyimide, but also introduces polyetheretherketone to form a binary alloy, thereby reducing the processing temperature, improving the polymer processing performance, and reducing the production and use costs.

[0028] The modification of carbon fiber reduces the probability of fiber shedding during wear, and reduces furrow wear and adhesive wear. The addition of graphene oxide further reduces the friction coefficient of the composite material, and can generate a stable lubricating transfer film under long-term high load. In addition, the introduction of carbon fiber can also reduce the thermal expansion coefficient of the material and increase dimensional stability.

[0029] The thermoplastic polyimide composite material prepared by the present invention has the characteristics of low wear, excellent mechanical properties, high temperature resistance, low warping deformation and creep resistance, and can be used as an ideal material for piston rings and applied in various harsh working conditions. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0031] The present embodiment provides a thermoplastic polyimide composite material for a piston ring, which is composed of the following materials in percentage by mass: 60-70% thermoplastic polyimide; 10-20% polyetheretherketone; 10-15% modified carbon fiber; 5-10% graphene oxide; 1-3% chain extender; 2% lubricant; and 0.5-1% antioxidant.

[0032] In this embodiment, the modified thermoplastic polyimide is tightly combined with the polyetheretherketone resin, which not only retains the dimensional stability and wear resistance of the thermoplastic polyimide, but also introduces polyetheretherketone to form a binary alloy, thereby reducing the processing temperature, improving the polymer processing performance, and reducing the production and use costs.

[0033] The modification of carbon fiber reduces the probability of fiber shedding during wear, and reduces furrow wear and adhesive wear. The addition of graphene oxide further reduces the friction coefficient of the composite material, and can generate a stable lubricating transfer film under long-term high load. In addition, the introduction of carbon fiber can also reduce the thermal expansion coefficient of the material and increase dimensional stability.

[0034] Furthermore, thermoplastic polyimide (TPI) is a known commercial product purchased from SABIC, Saudi Arabia, model: EXTEM XH1015.

[0035] Furthermore, polyetheretherketone (PEEK) is a well-known commercial product purchased from VICTREX, model: 450G.

[0036] Furthermore, graphene oxide (GO) is a known commercially available product purchased from Jiangsu Xianfeng Nanomaterial Technology Co., Ltd., model: XFSG01.

[0037] Furthermore, the silane coupling agent is a well-known commercially available product, Shanghai Aladdin Biochemical Technology Co., Ltd., model: KH550.

[0038] Furthermore, the lubricant may be YY-703A produced by Guangzhou Yuantai New Materials Co., Ltd.

[0039] Furthermore, the chain extender may be SA-U980 produced by QuanSheng Polycarbonate Technology Co., Ltd.

[0040] Furthermore, the antioxidant may be Irganox 1098 produced by BASF.

[0041] Furthermore, the carbon fiber (CF) can be T700 chopped carbon fiber 6 mm produced by Toray Industries, Japan.

[0042] As an improvement, the modified carbon fiber is prepared by the following method: first, the carbon fiber is oxidized by a mixed acid to obtain an oxidized carbon fiber, and then the oxidized carbon fiber is reacted with a silane coupling agent to prepare the modified carbon fiber, wherein the mixed acid is a mixture of concentrated sulfuric acid and concentrated nitric acid, and the volume ratio of the concentrated nitric acid to the concentrated sulfuric acid is 2-5:1.

[0043] Further, the concentrated sulfuric acid is a sulfuric acid aqueous solution with a mass fraction greater than or equal to 70%; the concentrated nitric acid is a nitric acid aqueous solution with a mass fraction greater than or equal to 60%. According to some specific and preferred aspects of the present invention, the feed mass ratio of the silane coupling agent to the oxidized carbon fiber is 1:200-800.

[0044] Further, the modified carbon fiber is prepared by the following method: first, the carbon fiber is cleaned with acetone, ultrasonically dispersed, and rinsed with clean water 3-5 times and dried after 4-6 hours; then the dried carbon fiber is immersed in a mixed acid solution of concentrated nitric acid and concentrated sulfuric acid with a volume ratio of 3:1, ultrasonically dispersed at 60-80°C, rinsed with distilled water 3-5 times after 30-120min, and vacuum dried at 80-100°C. The treated carbon fiber is immersed in a solution of silane coupling agent KH550, ethanol and distilled water in a ratio of 20:72:8, ultrasonically dispersed, rinsed with distilled water 3-5 times after 4-24 hours, and vacuum dried at 80-100°C to prepare a modified carbon fiber for standby use.

[0045] A method for preparing a thermoplastic polyimide composite material for a piston ring comprises the following steps:

[0046] (1) Weigh each raw material according to the formula, and dry the weighed thermoplastic polyimide and polyetheretherketone.

[0047] (2) The thermoplastic polyimide, polyetheretherketone, antioxidant and chain extender dried in step (1) are mixed in a high-speed mixer for 5 minutes and then melt-extruded to form a TPI alloy material.

[0048] (3) The TPI alloy material in step (2) and other raw materials are mixed in a high-speed mixer for 10 minutes, and then melt-extruded to prepare a thermoplastic polyimide composite material.

[0049] Furthermore, the drying treatment in step (1) is carried out at a temperature of 160-170° C. and a drying time of 4-8 hours.

[0050] Further, the melt extrusion operation in step (2) and step (3) is carried out in an extruder. Preferably, the temperature of each section in the extruder is: 320-350°C in zone 1, 350-370°C in zone 2, 370-380°C in zone 3, 380-390°C in zone 4, 380-390°C in zone 5, 380-390°C in zone 6, 380-390°C in zone 7, 380-390°C in zone 8, 370-380°C in zone 9, 370-380°C in zone 10, and 395-400°C in zone 11, wherein the screw aspect ratio is 36-48 and the screw speed is 200-500rpm.

[0051] The thermoplastic polyimide composite material prepared by the present invention has the characteristics of low wear, excellent mechanical properties, high temperature resistance, low warping deformation and creep resistance, and can be used as an ideal material for piston rings and applied in various harsh working conditions.

[0052] <Example 1>

[0053] The present embodiment provides a thermoplastic polyimide composite material for a piston ring, which comprises, by weight, 60 parts of thermoplastic polyimide, 20 parts of polyetheretherketone, 5 parts of graphene oxide, 10 parts of modified carbon fiber, 3 parts of chain extender, 1.5 parts of lubricant, and 0.5 parts of antioxidant.

[0054] Its preparation method is:

[0055] (1) Weigh each raw material according to the formula, put the weighed thermoplastic polyimide and polyetheretherketone into an oven for drying at a temperature of 160° C. for 6 hours.

[0056] (2) The thermoplastic polyimide, polyetheretherketone, antioxidant and chain extender dried in step (1) are mixed in a high-speed mixer for 5 minutes and then melt-extruded to form a TPI alloy material.

[0057] (3) Mixing the TPI alloy material in step (2) with other raw materials in a high-speed mixer for 10 minutes, and then melt-extruding to prepare a thermoplastic polyimide composite material. The temperatures of the extruders in step (2) and step (3) are as follows: 320°C in zone 1, 340°C in zone 2, 370°C in zone 3, 380°C in zone 4, 390°C in zone 5, 390°C in zone 6, 390°C in zone 7, 390°C in zone 8, 380°C in zone 9, 380°C in zone 10, and 400°C in zone 11, wherein the aspect ratio of the screw is 44, and the screw speed is 255 rpm.

[0058] Injection molding sample, process settings: drying temperature 165℃, drying time 4 hours, injection molding machine front section temperature 370℃, middle section temperature 380℃, rear section temperature 390℃, nozzle temperature 400 degrees, back pressure 55MPa, injection pressure 90MPa, injection speed 75mm / s, mold temperature 160℃.

[0059] The properties of the injection molded samples are shown in Table 1 below:

[0060] Table 1

[0061]

[0062]

[0063] <Example 2>

[0064] The present embodiment provides a thermoplastic polyimide composite material for a piston ring, which comprises, by weight, 70 parts of thermoplastic polyimide, 10 parts of polyetheretherketone, 5 parts of graphene oxide, 10 parts of modified carbon fiber, 3 parts of chain extender, 1 part of lubricant, and 1 part of antioxidant.

[0065] Its preparation method is:

[0066] (1) Weigh each raw material according to the formula, put the weighed thermoplastic polyimide and polyetheretherketone into an oven for drying at a temperature of 160° C. for 6 hours.

[0067] (2) The thermoplastic polyimide, polyetheretherketone, antioxidant and chain extender dried in step (1) are mixed in a high-speed mixer for 5 minutes and then melt-extruded to form a TPI alloy material.

[0068] (3) Mixing the TPI alloy material in step (2) with other raw materials in a high-speed mixer for 10 minutes, and then melt-extruding to prepare a thermoplastic polyimide composite material. The temperatures of the extruders in step (2) and step (3) are as follows: 320°C in zone 1, 340°C in zone 2, 370°C in zone 3, 380°C in zone 4, 390°C in zone 5, 390°C in zone 6, 390°C in zone 7, 390°C in zone 8, 380°C in zone 9, 380°C in zone 10, and 400°C in zone 11, wherein the aspect ratio of the screw is 44, and the screw speed is 255 rpm.

[0069] Injection molding sample, process settings: drying temperature 165℃, drying time 4 hours, injection molding machine front section temperature 370℃, middle section temperature 380℃, rear section temperature 390℃, nozzle temperature 400 degrees, back pressure 55MPa, injection pressure 90MPa, injection speed 75mm / s, mold temperature 160℃.

[0070] The properties of the injection molded samples are shown in Table 2 below:

[0071] Table 2

[0072]

[0073]

[0074] <Example 3>

[0075] The present embodiment provides a thermoplastic polyimide composite material for a piston ring, which comprises, by weight, 62.5 parts of thermoplastic polyimide, 15 parts of polyetheretherketone, 10 parts of graphene oxide, 10 parts of modified carbon fiber, 1 part of chain extender, 1 part of lubricant, and 0.5 part of antioxidant.

[0076] Its preparation method is:

[0077] (1) Weigh each raw material according to the formula, put the weighed thermoplastic polyimide and polyetheretherketone into an oven for drying at a temperature of 160° C. for 6 hours.

[0078] (2) The thermoplastic polyimide, polyetheretherketone, antioxidant and chain extender dried in step (1) are mixed in a high-speed mixer for 5 minutes and then melt-extruded to form a TPI alloy material.

[0079] (3) Mixing the TPI alloy material in step (2) with other raw materials in a high-speed mixer for 10 minutes, and then melt-extruding to prepare a thermoplastic polyimide composite material. The temperatures of the extruders in step (2) and step (3) are as follows: 320°C in zone 1, 340°C in zone 2, 370°C in zone 3, 380°C in zone 4, 390°C in zone 5, 390°C in zone 6, 390°C in zone 7, 390°C in zone 8, 380°C in zone 9, 380°C in zone 10, and 400°C in zone 11, wherein the aspect ratio of the screw is 44, and the screw speed is 255 rpm.

[0080] Injection molding sample, process settings: drying temperature 165℃, drying time 4 hours, injection molding machine front section temperature 370℃, middle section temperature 380℃, rear section temperature 390℃, nozzle temperature 400 degrees, back pressure 55MPa, injection pressure 90MPa, injection speed 75mm / s, mold temperature 160℃.

[0081] The properties of the injection molded samples are shown in Table 3 below:

[0082] Table 3

[0083]

[0084]

[0085] <Example 4>

[0086] The present embodiment provides a thermoplastic polyimide composite material for a piston ring, which comprises, by weight, 60 parts of thermoplastic polyimide, 12 parts of polyetheretherketone, 8 parts of graphene oxide, 15 parts of modified carbon fiber, 2.5 parts of a chain extender, 2 parts of a lubricant, and 0.5 parts of an antioxidant.

[0087] Its preparation method is:

[0088] (1) Weigh each raw material according to the formula, put the weighed thermoplastic polyimide and polyetheretherketone into an oven for drying at a temperature of 160° C. for 6 hours.

[0089] (2) The thermoplastic polyimide, polyetheretherketone, antioxidant and chain extender dried in step (1) are mixed in a high-speed mixer for 5 minutes and then melt-extruded to form a TPI alloy material.

[0090] (3) Mixing the TPI alloy material in step (2) with other raw materials in a high-speed mixer for 10 minutes, and then melt-extruding to prepare a thermoplastic polyimide composite material. The temperatures of the extruders in step (2) and step (3) are as follows: 320°C in zone 1, 340°C in zone 2, 370°C in zone 3, 380°C in zone 4, 390°C in zone 5, 390°C in zone 6, 390°C in zone 7, 390°C in zone 8, 380°C in zone 9, 380°C in zone 10, and 400°C in zone 11, wherein the aspect ratio of the screw is 44, and the screw speed is 255 rpm.

[0091] Injection molding sample, process settings: drying temperature 165℃, drying time 4 hours, injection molding machine front section temperature 370℃, middle section temperature 380℃, rear section temperature 390℃, nozzle temperature 400 degrees, back pressure 55MPa, injection pressure 90MPa, injection speed 75mm / s, mold temperature 160℃.

[0092] The properties of the injection molded samples are shown in Table 4 below:

[0093] Table 4

[0094] project Eigenvalue unit Test Standards Tensile strength 5mm / min 127 MPa ASTM D638 Notched impact strength 112 J / m ASTM D256 Thermal deformation: 1.8MPa 291 ℃ ASTM D648 Linear thermal expansion coefficient 0-100℃ <![CDATA[1.7×10 -6 ]]> cm / cm / ℃ ASTM E831 Volume wear rate K <![CDATA[3.1×10 -7 ]]> <![CDATA[Cm 3 / N.m]]> ASTM G137

[0095] <Example 5>

[0096] The present embodiment provides a thermoplastic polyimide composite material for a piston ring, which comprises, by weight, 60 parts of thermoplastic polyimide, 10 parts of polyetheretherketone, 7 parts of graphene oxide, 20 parts of modified carbon fiber, 1.5 parts of a chain extender, 1 part of a lubricant, and 0.5 parts of an antioxidant.

[0097] Its preparation method is:

[0098] (1) Weigh each raw material according to the formula, put the weighed thermoplastic polyimide and polyetheretherketone into an oven for drying at a temperature of 160° C. for 6 hours.

[0099] (2) The thermoplastic polyimide, polyetheretherketone, antioxidant and chain extender dried in step (1) are mixed in a high-speed mixer for 5 minutes and then melt-extruded to form a TPI alloy material.

[0100] (3) Mixing the TPI alloy material in step (2) with other raw materials in a high-speed mixer for 10 minutes, and then melt-extruding to prepare a thermoplastic polyimide composite material. The temperatures of the extruders in step (2) and step (3) are as follows: 320°C in zone 1, 340°C in zone 2, 370°C in zone 3, 380°C in zone 4, 390°C in zone 5, 390°C in zone 6, 390°C in zone 7, 390°C in zone 8, 380°C in zone 9, 380°C in zone 10, and 400°C in zone 11, wherein the aspect ratio of the screw is 44, and the screw speed is 255 rpm.

[0101] Injection molding sample, process settings: drying temperature 165℃, drying time 4 hours, injection molding machine front section temperature 370℃, middle section temperature 380℃, rear section temperature 390℃, nozzle temperature 400 degrees, back pressure 55MPa, injection pressure 90MPa, injection speed 75mm / s, mold temperature 160℃.

[0102] The properties of the injection molded samples are shown in Table 5 below:

[0103] Table 5

[0104] project Eigenvalue unit Test Standards Tensile strength 5mm / min 133 MPa ASTM D638 Notched impact strength 136 J / m ASTM D256 Thermal deformation: 1.8MPa 290 ℃ ASTM D648 Linear thermal expansion coefficient 0-100℃ <![CDATA[2.2×10 -6 ]]> cm / cm / ℃ ASTM E831 Volume wear rate K <![CDATA[1.9×10 -7 ]]> <![CDATA[Cm 3 / N.m]]> ASTM G137

[0105] Comparative Example 1

[0106] The raw materials include, by weight: 79 parts of thermoplastic polyimide, 20 parts of polyetheretherketone, and 1 part of antioxidant.

[0107] Its preparation method is:

[0108] (1) Weigh each raw material according to the formula, put the weighed thermoplastic polyimide and polyetheretherketone into an oven for drying at a temperature of 160° C. for 6 hours.

[0109] (2) The thermoplastic polyimide, polyetheretherketone, antioxidant and chain extender dried in step (1) are mixed in a high-speed mixer for 5 minutes and then melt-extruded.

[0110] The temperatures of each section in the extruder are: 320°C in zone 1, 340°C in zone 2, 370°C in zone 3, 380°C in zone 4, 390°C in zone 5, 390°C in zone 6, 390°C in zone 7, 390°C in zone 8, 380°C in zone 9, 380°C in zone 10, and 400°C in zone 11. The screw aspect ratio is 44 and the screw speed is 255rpm.

[0111] Injection molding sample, process settings: drying temperature 165℃, drying time 4 hours, injection molding machine front section temperature 370℃, middle section temperature 380℃, rear section temperature 390℃, nozzle temperature 400 degrees, back pressure 55MPa, injection pressure 90MPa, injection speed 75mm / s, mold temperature 160℃.

[0112] The properties of the injection molded samples are shown in Table 6 below:

[0113] Table 6

[0114]

[0115]

[0116] The calculation method of volume wear rate in the above table is:

[0117] Where: K is the volume wear rate; △m is the mass difference of the sample before and after wear; p is the sample density; N is the load; L is the sliding friction distance.

[0118] From the data in the above table, it can be seen that the modified thermoplastic polyimide composite material has excellent wear resistance, heat resistance and mechanical properties, and a low linear thermal expansion coefficient. It is suitable for use as a piston ring in various working conditions.

[0119] The technical principle of the present invention is described above in combination with specific embodiments, but it should be noted that the above descriptions are only for explaining the principle of the present invention and cannot be interpreted as a specific limitation on the protection scope of the present invention in any way. Based on the explanation here, technicians in this field can think of other specific embodiments or equivalent replacements of the present invention without paying creative work, which will fall within the protection scope of the present invention.

Claims

1. A thermoplastic polyimide composite material for a piston ring, characterized in that: It is composed of the following materials by mass percentage:

2. The thermoplastic polyimide composite material for piston ring according to claim 1, characterized in that: Thermoplastic polyimide was purchased from Saudi Sabic, model: EXTEM XH1015; polyetheretherketone was purchased from VICTREX, model: 450G; graphene oxide was purchased from Jiangsu Xianfeng Nanomaterial Technology Co., Ltd., model: XFSG01; the lubricant can be YY-703A from Guangzhou Yuantai New Materials Co., Ltd.; the chain extender can be SA-U980 from Quansheng Polycarbon Technology Co., Ltd.; the antioxidant can be Irganox1098 from BASF; the carbon fiber is T700 chopped carbon fiber from Toray Corporation of Japan.

3. The thermoplastic polyimide composite material for piston ring according to claim 1, characterized in that: 60 parts of thermoplastic polyimide, 20 parts of polyetheretherketone, 5 parts of graphene oxide, 10 parts of modified carbon fiber, 3 parts of chain extender, 1.5 parts of lubricant, and 0.5 parts of antioxidant; Or, 70 parts of thermoplastic polyimide, 10 parts of polyetheretherketone, 5 parts of graphene oxide, 10 parts of modified carbon fiber, 3 parts of chain extender, 1 part of lubricant, and 1 part of antioxidant; Or, 62.5 parts of thermoplastic polyimide, 15 parts of polyetheretherketone, 10 parts of graphene oxide, 10 parts of modified carbon fiber, 1 part of chain extender, 1 part of lubricant, and 0.5 part of antioxidant; Or, 60 parts of thermoplastic polyimide, 12 parts of polyetheretherketone, 8 parts of graphene oxide, 15 parts of modified carbon fiber, 2.5 parts of chain extender, 2 parts of lubricant, and 0.5 parts of antioxidant; Or, 60 parts of thermoplastic polyimide, 10 parts of polyetheretherketone, 7 parts of graphene oxide, 20 parts of modified carbon fiber, 1.5 parts of chain extender, 1 part of lubricant, and 0.5 part of antioxidant.

4. A method for preparing the thermoplastic polyimide composite material for piston rings according to any one of claims 1 to 3, characterized in that: The following steps are involved: S100: weighing various raw materials according to the formula, and drying the weighed thermoplastic polyimide and polyetheretherketone; S200: mixing the thermoplastic polyimide, polyetheretherketone, antioxidant and chain extender dried in step S100 in a high-speed mixer for 5 minutes and then melt-extruding to form a TPI alloy material; S300: The TPI alloy material in step S200 is mixed with other raw materials in a high-speed mixer for 10 minutes, and then melt-extruded to form a thermoplastic polyimide composite material.

5. The method for preparing the thermoplastic polyimide composite material for piston ring according to claim 4, characterized in that: The drying process in step S100 is performed at a temperature of 160-170° C. and a drying time of 4-8 hours.

6. The method for preparing the thermoplastic polyimide composite material for piston ring according to claim 5, characterized in that: The melt extrusion operation in step S200 and step S300 is carried out in an extruder, and the temperatures of each section in the extruder are: 320-350°C in zone 1, 350-370°C in zone 2, 370-380°C in zone 3, 380-390°C in zone 4, 380-390°C in zone 5, 380-390°C in zone 6, 380-390°C in zone 7, 380-390°C in zone 8, 370-380°C in zone 9, 370-380°C in zone 10, and 395-400°C in zone 11, wherein the screw aspect ratio is 36-48, and the screw speed is 200-500rpm.

7. The method for preparing a thermoplastic polyimide composite material for a piston ring according to claim 4, characterized in that: The modified carbon fiber is prepared by the following method: Step 1: first oxidizing the carbon fiber with a mixed acid to obtain oxidized carbon fiber; Step 2: reacting the oxidized carbon fiber with a silane coupling agent to prepare the modified carbon fiber, wherein the mixed acid is a mixture of concentrated sulfuric acid and concentrated nitric acid, and the volume ratio of the concentrated nitric acid to the concentrated sulfuric acid is 2-5:

1.

8. The method for preparing a thermoplastic polyimide composite material for a piston ring according to claim 7, characterized in that: The concentrated sulfuric acid is a sulfuric acid aqueous solution with a mass fraction greater than or equal to 70%; the concentrated nitric acid is a nitric acid aqueous solution with a mass fraction greater than or equal to 60%; the feed mass ratio of the silane coupling agent to the oxidized carbon fiber is 1:200-800.

9. The method for preparing a thermoplastic polyimide composite material for a piston ring according to claim 8, characterized in that: In step one, first, the carbon fiber is cleaned with acetone, ultrasonically dispersed, and rinsed with clean water 3-5 times and dried after 4-6 hours; then the dried carbon fiber is immersed in a mixed acid solution of concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 3:1, ultrasonically dispersed at 60-80°C, rinsed with distilled water 3-5 times after 30-120 minutes, and vacuum dried at 80-100°C; in step two, the treated carbon fiber is immersed in a solution of silane coupling agent KH550, ethanol and distilled water in a ratio of 20:72:8, ultrasonically dispersed, rinsed with distilled water 3-5 times after 4-24 hours, and vacuum dried at 80-100°C to prepare modified carbon fiber for standby use.

10. A piston ring, characterized in that: The piston ring is made of the thermoplastic polyimide composite material as claimed in any one of claims 1 to 3.

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