Wear-resistant peek composite material and its application in reversing valve for wind bag pump

Abstract

The application provides a wear-resistant PEEK composite material and application thereof in a reversing valve of a wind bag pump, and relates to the technical field of the wind bag pump.The wear-resistant PEEK composite material comprises the following raw materials in parts by weight: PEEK 100 parts, aramid fiber 2-5 parts, and siloxane modified carbon fiber 5-10 parts.The material takes PEEK as a base material, aramid fiber and siloxane modified carbon fiber are added, and the components cooperate with each other, so that the obtained wear-resistant PEEK composite material has excellent impact resistance, wear resistance and heat resistance, and the processing technology is simple, and the material is suitable for wide promotion.

Description

Technical Field

[0001] This invention relates to the field of airbag pump technology, and in particular to a wear-resistant PEEK composite material and its application in a reversing valve for airbag pumps. Background Technology

[0002] A pneumatic airbag pump is a type of pump that uses a variable-volume airbag within the pump cylinder to alternately increase and decrease its working volume to transport special liquids. It is widely used, especially in the semiconductor and electronics industries, and is commonly used to transport highly corrosive special solutions such as strong acids and alkalis. The directional control valve is a crucial component of the pneumatic airbag pump, primarily used to facilitate the connection, disconnection, and reversal of hydraulic oil flow. The directional control valve relies mainly on the relative movement between the valve core and the valve body. Frequent friction of the valve core leads to significant wear over prolonged use, and frequent replacement increases production costs. This necessitates a valve core structure with high wear resistance and mechanical strength to increase service life, reduce replacement frequency, and lower costs.

[0003] Polyetheretherketone (PEEK) is a semi-crystalline aromatic thermoplastic engineering plastic with advantages such as high temperature resistance, high elasticity, high modulus, good dimensional stability, corrosion resistance, and good wear resistance. Currently, pure PEEK is used in valve bodies, valve cores, and valve sleeves of directional control valves. Although PEEK has good wear resistance, it still suffers from significant wear loss due to friction, and its impact strength needs improvement, making it unsuitable for prolonged operation of the directional control valve in a ventilator pump. Adding reinforcing materials such as glass fiber, carbon fiber, graphene, and carbon nanotubes is an important method to improve the material's friction performance. However, conventional reinforcing materials have poor compatibility with PEEK, affecting the overall performance of the composite material. While surface-treated reinforcing materials improve compatibility with PEEK, they cannot simultaneously enhance the wear resistance and impact resistance of PEEK. Therefore, it is necessary to provide a material with good wear resistance that can withstand the working pressure of a ventilator pump for extended periods. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a wear-resistant PEEK composite material and its application in a reversing valve for a wind pump.

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

[0006] On the one hand, a wear-resistant PEEK composite material comprises the following raw materials in parts by weight: 100 parts PEEK, 2-5 parts aramid fiber, and 5-10 parts siloxane-modified carbon fiber.

[0007] Preferably, the wear-resistant PEEK composite material comprises the following raw materials in parts by weight: 100 parts PEEK, 3 parts aramid fiber, and 7 parts siloxane-modified carbon fiber.

[0008] Furthermore, the diameter of the siloxane-modified carbon fiber is 1–5 μm and the length is 0.5–5 mm.

[0009] Furthermore, the siloxane-modified carbon fiber is obtained by impregnating and modifying carbon fiber with amino-terminated polydimethylsiloxane.

[0010] Furthermore, the amino-terminated polydimethylsiloxane has a weight-average molecular weight of 5,000 to 20,000 and an amino content of 0.1 to 0.5 mmol / g.

[0011] Specifically, the siloxane-modified carbon fiber is prepared by the following method:

[0012] (1) At 100-120℃, carbon fibers are treated with an oxidant for 4-6 hours to obtain surface-oxidized carbon fibers. The oxidant is selected from nitric acid, acidic potassium dichromate, sodium hypochlorite, hydrogen peroxide or potassium persulfate. The surface oxidation process is to place the carbon fibers in an aqueous solution of the oxidant for a period of time, and then take them out and wash off the residual oxidant on the surface with water. The mass fraction of the aqueous solution is generally >10%, such as 30% nitric acid solution.

[0013] (2) Add amino-terminated polydimethylsiloxane to acetone, add surface-oxidized carbon fiber, the mass ratio of amino-terminated polydimethylsiloxane to surface-oxidized carbon fiber is (2-3):10, preferably 2.4:10; immerse at room temperature for 6-8 hours, wash and dry after treatment to obtain the product.

[0014] Furthermore, the aramid fiber has a diameter of 5–12 μm and a length of 5–10 mm.

[0015] In a further embodiment, the aramid fiber is a plasma-treated aramid fiber. During the plasma treatment process, the treatment medium is air, oxygen, nitrogen, or argon, the gas flow rate is 10 cm / min to 3100 cm / min, the plasma generation power is 50 W to 300 W, and the treatment time is 50 s to 300 s.

[0016] Further, the PEEK contains 20-30% carboxylated PEEK, i.e., the mass ratio of PEEK to carboxylated PEEK is (70-80):(20-30), preferably 26% carboxylated PEEK; the degree of carboxylation of the carboxylated PEEK is 18-25%, preferably 20%; the carboxylated PEEK is prepared by the following method:

[0017] 4,4-Difluorobenzophenone, hydroquinone, 3,5-dihydroxybenzoic acid, alkali metal carbonate, and toluene were mixed and polymerized under nitrogen protection. After the reaction was completed, the mixture was poured into water, acidified with hydrochloric acid, washed, and dried to obtain the final product.

[0018] This application prepares carboxylated PEEK by reacting three monomers: 4,4-difluorobenzophenone, hydroquinone, and dihydroxybenzoic acid. By controlling the molar ratio of dihydroxybenzoic acid in the three monomers to be 18-25%, PEEK with a carboxylation degree of 18-25% is obtained, giving it excellent heat resistance. Combined with PEEK as a base material for wear-resistant materials, and in conjunction with other components, it can impart good heat resistance, wear resistance, and impact resistance to the wear-resistant materials. In the above-mentioned preparation process of carboxylated PEEK, except that the molar ratio of dihydroxybenzoic acid needs to be controlled within the range of 18-25%, the molar ratios of 4,4-difluorobenzophenone and hydroquinone are preferably 50-70% and 12-25%, respectively; the alkali metal carbonate is preferably potassium carbonate and / or sodium carbonate, and its amount is generally not less than 20% of the total mass of the three monomers, preferably 20-30%; the amount of solvent toluene is adjusted according to the actual amount used, just enough to dissolve the monomers, and usually excess toluene is used. The polymerization reaction is carried out at a temperature of 200–250°C. Preferably, prepolymerization is carried out at 200–210°C for 1–2 hours, followed by polymerization at 240–250°C for 1–2 hours. The acidification process is adjusted according to the required degree of carboxylation by adjusting the amount of hydrochloric acid and the acidification time. Specifically, the temperature is raised to 150–160°C and held for 1–2 hours, then raised to 200–210°C for prepolymerization for 1–1.5 hours while distilling off the remaining toluene. The temperature is then raised to 240–250°C and held for 1–2 hours for polymerization. After the reaction is completed, the product is poured into water, acidified with hydrochloric acid for 6 hours, washed with ethanol and water respectively, and dried to obtain the final product.

[0019] On the other hand, the preparation method of the above-mentioned wear-resistant PEEK composite material includes the following steps:

[0020] After thoroughly mixing PEEK, aramid fiber, and siloxane-modified carbon fiber, the mixture is placed in a mold and hot-pressed at a temperature of 390–400°C and a pressure of 10–15 MPa. Then, it is annealed to obtain the final product.

[0021] Furthermore, the annealing treatment temperature is 250–260°C, and the time is 1–2 hours.

[0022] On the other hand, the aforementioned wear-resistant PEEK composite material is used in the preparation of directional valves for windshield pumps.

[0023] Furthermore, the application includes using wear-resistant PEEK composite materials to prepare at least one of the valve body, valve sleeve, and valve core in a reversing valve for a windshield pump.

[0024] Compared with the prior art, this application has the following beneficial effects:

[0025] 1. The wear-resistant PEEK composite material of this application incorporates aramid fiber and amino-terminated polydimethylsiloxane-modified carbon fiber, which are then combined with PEEK to improve the impact resistance and wear resistance of the PEEK material. The processing technology is simple and suitable for widespread application.

[0026] 2. The wear-resistant PEEK composite material of this application incorporates amino-terminated polydimethylsiloxane-modified carbon fibers. Compared with carbon fibers, the amino-terminated polydimethylsiloxane-modified carbon fibers can better disperse and bond in PEEK materials, improve interfacial compatibility, reduce the generation of interfacial defects, improve friction resistance, alleviate interfacial stress concentration under external force, and improve impact resistance. In addition, the amino-terminated polydimethylsiloxane structure can also provide a certain degree of protection for PEEK at high temperatures, thereby improving high-temperature resistance.

[0027] 3. In this application, aramid fibers are added to the wear-resistant PEEK composite material. Aramid fibers have high tensile strength, good impact performance, high elastic modulus, and good thermal stability. Adding a certain amount of aramid fibers helps to improve the impact resistance and wear resistance of the material. However, aramid fibers have strong surface inertness and poor compatibility with PEEK, and are prone to agglomeration in PEEK materials. This application introduces active groups by plasma treatment of the aramid surface, which enhances the interfacial bonding with PEEK, thereby better improving the impact resistance and wear resistance of the material.

[0028] 4. The PEEK in this application contains a certain amount of carboxylated PEEK. The presence of carboxylated PEEK can react with aramid fibers and carbon fibers to form a stable chemical bond, thereby enhancing the interfacial bonding force between the components, while also retaining the high temperature resistance and corrosion resistance properties of PEEK materials.

[0029] 5. The wear-resistant PEEK composite material of this application, through the combined effect of the above-mentioned aspects, effectively improves wear resistance and impact resistance, reduces the coefficient of friction to below 0.1, and achieves a maximum impact strength of 40 kJ / m. 2 above. Detailed Implementation

[0030] The following non-limiting embodiments are intended to enable those skilled in the art to gain a more comprehensive understanding of the present invention, but do not limit the invention in any way. The following content is merely an exemplary description of the scope of protection of the present invention, and those skilled in the art can make various changes and modifications to the invention based on the disclosed content, which should also fall within the scope of protection of the present invention.

[0031] Unless otherwise specified, all chemical reagents used in the embodiments of this invention are obtained through conventional commercial channels. Specifically, the amino-terminated polydimethylsiloxane can be purchased directly or prepared using existing methods, without particular limitations, as long as its molecular weight and amino content are met. In the following specific embodiments, PEEK, 3,5-dihydroxybenzoic acid, and 4,4-difluorobenzophenone were purchased from Hubei Jusheng Technology Co., Ltd. The invention will be further described below by way of specific embodiments.

[0032] Example 1

[0033] A wear-resistant PEEK composite material comprises the following raw materials in parts by weight: 100 parts PEEK, 2 parts aramid fiber, and 10 parts siloxane-modified carbon fiber; wherein,

[0034] Siloxane-modified carbon fibers were prepared by the following method:

[0035] Carbon fibers were treated with a 30% nitric acid solution at 100℃ for 4 hours to obtain surface-oxidized carbon fibers. Amino-terminated polydimethylsiloxane (weight average molecular weight of 5000, amino content of 0.1 mmol / g) was added to sufficient acetone, followed by the surface-oxidized carbon fibers. The mass ratio of amino-terminated polydimethylsiloxane to surface-oxidized carbon fibers was 2:10. The mixture was impregnated at room temperature for 6 hours. After treatment, the carbon fibers were washed and dried to obtain the final product, which had a diameter of 1 μm and a length of 0.5 mm.

[0036] The aramid fiber has a diameter of 5μm and a length of 5mm.

[0037] The wear-resistant PEEK composite material was prepared by the following method:

[0038] After thoroughly mixing PEEK, aramid fiber, and siloxane-modified carbon fiber, the mixture is placed in a mold and hot-pressed at a temperature of 390℃ and a pressure of 10MPa. Then, it is annealed at a temperature of 250℃ for 1 hour to obtain the final product.

[0039] Example 2

[0040] A wear-resistant PEEK composite material comprises the following raw materials in parts by weight: 100 parts PEEK, 3 parts aramid fiber, and 7 parts siloxane-modified carbon fiber; wherein,

[0041] Siloxane-modified carbon fibers were prepared by the following method:

[0042] Carbon fibers were treated with a 30% nitric acid solution at 100℃ for 6 hours to obtain surface-oxidized carbon fibers. Amino-terminated polydimethylsiloxane (weight average molecular weight of 20,000, amino content of 0.5 mmol / g) was added to sufficient acetone, and then surface-oxidized carbon fibers were added. The mass ratio of amino-terminated polydimethylsiloxane to surface-oxidized carbon fibers was 2.4:10. The mixture was impregnated at room temperature for 8 hours. After treatment, the carbon fibers were washed and dried to obtain the final product, which had a diameter of 1 μm and a length of 0.5 mm.

[0043] The aramid fiber is a plasma-treated aramid fiber with a diameter of 12μm and a length of 10mm. The plasma treatment medium is argon gas with a flow rate of 10cm / min, a plasma generation power of 50W, and a treatment time of 50s.

[0044] The wear-resistant PEEK composite material was prepared by the following method:

[0045] After thoroughly mixing PEEK, aramid fiber, and siloxane-modified carbon fiber, the mixture is placed in a mold and hot-pressed at a temperature of 390℃ and a pressure of 10MPa. Then, it is annealed at a temperature of 250℃ for 1 hour to obtain the final product.

[0046] Example 3

[0047] A wear-resistant PEEK composite material comprises the following raw materials in parts by weight: 70 parts PEEK, 30 parts carboxylated PEEK, 5 parts aramid fiber, and 5 parts siloxane-modified carbon fiber; wherein,

[0048] Siloxane-modified carbon fibers were prepared by the following method:

[0049] Carbon fibers were treated with a 30% nitric acid solution at 100℃ for 6 hours to obtain surface-oxidized carbon fibers. Amino-terminated polydimethylsiloxane (weight average molecular weight of 20,000, amino content of 0.5 mmol / g) was added to sufficient acetone, and then surface-oxidized carbon fibers were added. The mass ratio of amino-terminated polydimethylsiloxane to surface-oxidized carbon fibers was 3:10. The mixture was impregnated at room temperature for 8 hours. After treatment, the carbon fibers were washed and dried to obtain the final product, which had a diameter of 1 μm and a length of 0.5 mm.

[0050] The aramid fiber is a plasma-treated aramid fiber with a diameter of 12μm and a length of 10mm. The plasma treatment medium is argon gas with a flow rate of 10cm / min, a plasma generation power of 50W, and a treatment time of 50s.

[0051] The carboxymethylation degree of carboxylated PEEK is 18%, and the preparation method is as follows:

[0052] 4,4-Difluorobenzophenone, hydroquinone, 3,5-dihydroxybenzoic acid, alkali metal carbonate, and sufficient toluene were mixed. The molar ratio of 4,4-difluorobenzophenone, hydroquinone, and 3,5-dihydroxybenzoic acid was 70:18:12. Potassium carbonate and sodium carbonate were used at 10% of the total mass of the three monomers, respectively. The mixture was prepolymerized at 200°C for 1 hour under nitrogen protection, and then polymerized at 240°C for 1 hour. After the reaction was completed, the mixture was poured into water, acidified with hydrochloric acid, washed, and dried to obtain the final product.

[0053] The wear-resistant PEEK composite material was prepared by the following method:

[0054] After thoroughly mixing PEEK, aramid fiber, and siloxane-modified carbon fiber, the mixture is placed in a mold and hot-pressed at a temperature of 390℃ and a pressure of 10MPa. Then, it is annealed at a temperature of 250℃ for 1 hour to obtain the final product.

[0055] Example 4

[0056] The difference from Example 3 is that the amount of PEEK added is 74 parts, the amount of carboxylated PEEK is 26 parts, and the degree of carboxylation of the carboxylated PEEK is 20%. PEEK with a degree of carboxylation of 20% can be obtained by adjusting the amount of monomer, which will not be described in detail here.

[0057] Example 5

[0058] The difference from Example 3 is that the amount of PEEK added is 80 parts, the amount of carboxylated PEEK is 20 parts, and the degree of carboxymethylation of the carboxylated PEEK is 25%.

[0059] Example 6

[0060] The difference from Example 3 is that, in the preparation process of siloxane-modified carbon fiber, the mass ratio of amino-terminated polydimethylsiloxane to surface-oxidized carbon fiber is 4:10.

[0061] Example 7

[0062] The difference from Example 3 is that the amount of PEEK added is 60 parts and the amount of carboxylated PEEK is 40 parts.

[0063] Example 8

[0064] The difference from Example 3 is that the degree of carboxylation of carboxylated PEEK is 30%.

[0065] Comparative Example 1

[0066] The difference from Example 3 is that, in the preparation process of siloxane-modified carbon fiber, the amino-terminated polydimethylsiloxane is replaced with an equal amount of γ-aminopropyltriethoxysilane.

[0067] Comparative Example 2

[0068] The difference from Example 3 is that the siloxane-modified carbon fiber is replaced with untreated carbon fiber.

[0069] Comparative Example 3

[0070] The difference from Example 3 is that no siloxane-modified carbon fiber is added.

[0071] Test case

[0072] Impact strength, abrasion resistance, and heat resistance tests were conducted on the wear-resistant PEEK composite materials prepared in the above embodiments and comparative examples. Impact strength was tested according to ASTM D256-2010, abrasion resistance was tested according to GB / T 3960-2016, and the wear rate was used to characterize the friction properties. Heat resistance was tested at 1.86 MPa according to ASTM D648. The results are shown in Table 1 below.

[0073] Table 1

[0074]

[0075] The results show that the impact strength of the PEEK composite material provided by the present invention is 38 kJ / m. 2 The coefficient of friction is ≤0.1 and the heat distortion temperature is higher than 240℃. That is, the PEEK composite material of this application has excellent impact resistance, friction resistance and heat resistance, which makes up for the defects of existing PEEK materials.

[0076] Compared to Example 3, the impact strength, wear resistance, and heat resistance of the materials obtained in Comparative Examples 1-3 all decreased. In Example 6, the siloxane-modified carbon fiber contained an excessive amount of siloxane, which reduced its impact resistance and heat distortion temperature. This shows that the addition of siloxane-modified carbon fiber helps to improve the performance of the material, but the amount of siloxane in the carbon fiber needs to be controlled.

[0077] In summary, the PEEK composite material provided by this invention has excellent impact resistance, wear resistance, and heat resistance, thus overcoming the shortcomings of existing PEEK materials for ball valves.

[0078] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A wear-resistant PEEK composite material, characterized in that, It contains the following raw materials in parts by weight: 100 parts PEEK, 2-5 parts aramid fiber, and 5-10 parts siloxane-modified carbon fiber; The PEEK contains 20-30% carboxylated PEEK, and the degree of carboxylation of the carboxylated PEEK is 18-25%. The method for preparing the siloxane-modified carbon fiber includes the following steps: (1) At 100-120℃, carbon fibers are treated with an oxidant for 4-6 hours to obtain surface-oxidized carbon fibers; (2) Add amino-terminated polydimethylsiloxane to acetone, add surface-oxidized carbon fiber, and impregnate at room temperature for 6-8 hours. After treatment, wash and dry to obtain the product. In the preparation of siloxane-modified carbon fiber, the mass ratio of amino-terminated polydimethylsiloxane to surface-oxidized carbon fiber is (2-3):

10.

2. The wear-resistant PEEK composite material according to claim 1, characterized in that, The siloxane-modified carbon fiber has a diameter of 1–5 μm and a length of 0.5–5 mm.

3. The wear-resistant PEEK composite material according to claim 1, characterized in that, The amino-terminated polydimethylsiloxane has a weight-average molecular weight of 5,000 to 20,000 and an amino content of 0.1 to 0.5 mmol / g.

4. The wear-resistant PEEK composite material according to claim 1, characterized in that, The aramid fiber has a diameter of 5–12 μm and a length of 5–10 mm.

5. The method for preparing the wear-resistant PEEK composite material according to any one of claims 1-4, characterized in that, Includes the following steps: After thoroughly mixing PEEK, aramid fiber, and siloxane-modified carbon fiber, the mixture is placed in a mold and hot-pressed at a temperature of 390–400°C and a pressure of 10–15 MPa. Then, it is annealed to obtain the final product.

6. The application of the wear-resistant PEEK composite material according to any one of claims 1-4 or the wear-resistant PEEK composite material prepared by the preparation method according to claim 5 in the preparation of a reversing valve for a windshield pump.

7. The application according to claim 6, characterized in that, The application includes the use of wear-resistant PEEK composite materials to prepare at least one of the valve body, valve sleeve, and valve core in a reversing valve for a windshield pump.

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