Preparation method of high-performance modified antistatic composite material

Abstract

The invention relates to a preparation method of a high-performance modified anti-static composite material, and belongs to the technical field of preparation of anti-static materials. According to the preparation method, surface oxidation treatment is carried out on the carbon fibers through the nitric acid solution, then 2, 5-dimethylthiophene is subjected to in-situ polymerization on the surfaces of the fibers to form a conjugated polythiophene layer, intrinsic conductivity is improved, environmental erosion is blocked, and antistatic durability is maintained. The epoxy resin and polycarbonate blended matrix are combined to achieve high strength and toughness, the CTAB modified nano-montmorillonite achieves nanoscale dispersion, the rigidity and thermal stability of the material are enhanced, and the CTAB modified nano-montmorillonite and the carbon fibers cooperate to improve the strength and modulus. The polyoxyethylene alkyl ether reduces surface resistance by forming a conductive water film, promotes fiber dispersion as a lubricant, and synergistically covers the wide temperature and humidity antistatic requirements with the modified carbon fiber. The composite material prepared by the invention has excellent mechanical properties, conductivity and durability.

Description

Technical Field

[0001] The invention belongs to the technical field of antistatic material preparation, and relates to a method for preparing a high-performance modified antistatic composite material. Background Art

[0002] With the rapid development of the electronics, aerospace, petrochemical, and medical device industries, material performance requirements are increasing. Antistatic performance, a key performance indicator, is directly related to product safety, reliability, and service life. In electronic device manufacturing, static electricity accumulation can cause electronic component breakdown or failure; in aerospace, static discharge can disrupt the normal operation of sensitive instruments; and in the petrochemical industry, static sparks can cause explosions and other serious accidents. Therefore, the development of high-performance antistatic composite materials has important practical significance and application value.

[0003] Traditional antistatic materials are mainly divided into two categories: surface conductive type and volume conductive type. Surface conductive materials achieve antistatic function by coating a conductive coating or plating a conductive layer on the surface of the material, but there are disadvantages such as easy wear and shedding of the coating, and unstable conductivity. Volume conductive materials achieve overall conductivity of the material by adding conductive fillers to the matrix material to form a conductive network. However, factors such as the amount of conductive filler added, its dispersibility, and its compatibility with the matrix material directly affect the antistatic performance and mechanical properties of the composite material. Therefore, there is an urgent need to develop a low-cost, high-performance and environmentally friendly method for preparing antistatic composite materials. Summary of the Invention

[0004] The invention provides a method for preparing a high-performance modified antistatic composite material, which has excellent antistatic effect.

[0005] A method for preparing a high-performance modified antistatic composite material, the specific steps of the preparation method are as follows: S1-1: 10 to 20 parts by weight of carbon fiber were immersed in 100 parts by weight of a 6 to 8 M nitric acid solution, ultrasonically treated at 60 to 80°C for 1 to 2 hours, washed with deionized water, and vacuum dried at 60°C for 12 hours to obtain carbon fiber A; S1-2: Add 5 to 15 parts by weight of carbon fiber A to 50 parts by weight of a 0.1 to 0.2 M 2,5-dimethylthiophene solution, add dropwise a 0.2 to 0.4 M ferric chloride solution, stir at 25 to 35 ° C for 4 to 8 hours, then wash with methanol and deionized water, and place under vacuum drying at 60 ° C for 12 hours to obtain modified carbon fiber; S1-3: 60-80 parts by weight of epoxy resin and 20-40 parts by weight of polycarbonate are mixed, 3-5 parts by weight of modified nano-montmorillonite and 0.5-1.5 parts by weight of hindered amine light stabilizer are added, and the mixture is dispersed at 55-65° C. for 20-40 minutes to obtain a matrix material; S1-4: Mix 5 to 10 parts by weight of modified carbon fiber with 90 to 95 parts by weight of matrix material for 10 to 20 minutes, add 1 to 2 parts by weight of polyoxyethylene alkyl ether solution, and extrude the mixture through a twin-screw extruder at a temperature of 150 to 170°C and a rotation speed of 650 to 750 rpm to obtain the high-performance modified antistatic composite material.

[0006] As a preferred technical solution of the present invention, the frequency of the ultrasonic treatment in S1-1 is 5 to 6 kHz, and the power of the ultrasonic treatment is 200 to 300 W.

[0007] As a preferred technical solution of the present invention, the dropping speed of the ferric chloride solution in S1-2 is 1 to 2 mL / min.

[0008] As a preferred technical solution of the present invention, the molar ratio of ferric chloride to 2,5-dimethylthiophene in S1-2 is 2:1.

[0009] As a preferred technical solution of the present invention, the dispersion speed in S1-3 is 1000-2000 rpm.

[0010] As a preferred technical solution of the present invention, the hindered amine light stabilizer includes but is not limited to light stabilizer 791, light stabilizer 944, and light stabilizer 783.

[0011] As a preferred technical solution of the present invention, the modified nano-montmorillonite in S1-3 is nano-montmorillonite modified with 1-3 wt% of hexadecyltrimethylammonium bromide.

[0012] As a preferred technical solution of the present invention, the mass fraction of the polyoxyethylene alkyl ether solution in S1-4 is 5% to 10%, and the solvent is acetone.

[0013] Surface oxidation of carbon fibers with nitric acid solution effectively removes surface impurities and introduces oxygen-containing functional groups such as carboxyl and hydroxyl groups, significantly increasing the surface activity of the fibers and providing active sites for subsequent interfacial reactions. Ultrasonic-assisted treatment enhances the contact efficiency between the oxidant and the fiber surface through the cavitation effect, promoting etching and forming micron-scale groove structures, further increasing the fiber specific surface area. Surface oxidation and roughening work synergistically, on the one hand, enhancing the interfacial bonding strength between the carbon fibers and the polymer matrix through a mechanical locking effect, reducing interfacial resistance; on the other hand, providing physical anchoring points for the uniform deposition of the subsequent polythiophene conductive layer, optimizing the continuity of the conductive network.

[0014] 2,5-Dimethylthiophene undergoes chemical oxidation polymerization on the carbon fiber surface under the action of ferric chloride, forming an in-situ conjugated polythiophene layer, which significantly enhances the carbon fiber's intrinsic conductivity and forms chemical bonds with the functional groups on the fiber surface, ensuring the long-term stability of the conductive network. Furthermore, the high chemical stability of the polythiophene layer effectively blocks environmental corrosive media such as oxygen and moisture, protecting the carbon fiber from corrosion and thus maintaining the long-term antistatic effect.

[0015] Epoxy resin and polycarbonate are blended in a specific mass ratio. The epoxy resin's cross-linked network provides high strength, while the polycarbonate's toughness optimizes the composite's impact resistance. CTAB-modified nano-montmorillonite effectively prevents aggregation, forming a nanoscale dispersed structure and improving the composite's uniformity. The exfoliated nano-sheets effectively inhibit crack propagation and enhance the material's toughness. The modified nano-montmorillonite restricts polymer chain motion through intercalation, enhancing the matrix's rigidity and thermal stability. The nano-montmorillonite's layered structure creates a reinforcing effect with carbon fibers. The carbon fibers bear axial loads, while the nano-sheets inhibit transverse crack propagation, ultimately improving the composite's strength and modulus. Hindered amine light stabilizers (HALSs) inhibit UV-induced photooxidative degradation by capturing free radicals, delaying yellowing and mechanical property degradation, significantly extending the material's service life. The nano-montmorillonite's layered structure physically adsorbs HALS molecules, reducing volatilization losses during processing and extending the material's photostability lifetime.

[0016] The polyoxyethylene segments in the polyoxyethylene alkyl ether molecular chain act as strong hydrophilic groups, adsorbing water molecules from the air and forming a conductive water film on the composite surface, thereby reducing surface resistance and meeting transient antistatic requirements. As a lubricant, polyoxyethylene alkyl ether reduces internal friction in the composite during twin-screw extrusion, promoting uniform dispersion of the modified carbon fibers and reducing agglomeration defects. Furthermore, the alkyl chains of the polyoxyethylene alkyl ether form weak interactions with the polythiophene layer on the carbon fiber surface through van der Waals forces, enhancing interfacial bonding and, in turn, increasing the tensile strength and flexural modulus of the composite. The polyoxyethylene alkyl ether and modified carbon fibers exhibit synergistic antistatic properties: the modified carbon fibers provide long-term conductivity, while the polyoxyethylene alkyl ether supplements the transient antistatic capacity through the conductive water film. This combination addresses antistatic requirements across a wide temperature and humidity range. Furthermore, the alkyl chains of the polyoxyethylene alkyl ether reduce the surface energy of the polythiophene layer, promoting wetting of the matrix resin on the fiber surface, reducing porosity, and improving the density of the composite. Polyoxyethylene alkyl ether also has a protective effect on hindered amine light stabilizers, which can reduce the decomposition and volatilization of hindered amine light stabilizers during processing and use, prolong the light stabilization effect, and ensure the long-term weather resistance of the material.

[0017] Beneficial effects of the present invention: In the present invention, the carbon fibers are oxidized with nitric acid and ultrasonically treated to introduce oxygen-containing functional groups and form a micron-scale groove structure, thereby enhancing interfacial bonding and conductive layer deposition. In-situ polymerization of the polythiophene layer improves conductivity and blocks environmental erosion, maintaining durable antistatic properties. The epoxy resin / polycarbonate blend combines high strength and toughness, while CTAB-modified nano-montmorillonite achieves nano-scale dispersion, hindering crack propagation and enhancing matrix rigidity and thermal stability, while also forming a dual reinforcement effect with the carbon fibers. The hindered amine light stabilizer inhibits photooxidative degradation, while the nano-montmorillonite adsorbs its molecules to reduce volatility and extend the light stability life. Polyoxyethylene alkyl ether forms a conductive water film to reduce surface resistance, acting as a lubricant to promote fiber dispersion. Its alkyl chain enhances interfacial bonding, synergistically modifying the modified carbon fibers to cover wide temperature and humidity antistatic requirements, and reducing the surface energy of the polythiophene layer, reducing porosity, and improving density, thereby comprehensively improving the mechanical, conductive, and weather resistance properties of the composite material. DETAILED DESCRIPTION

[0018] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with the embodiments.

[0019] In the Examples of the present invention and the Comparative Examples: Carbon fiber: purchased from Zhejiang Yamei Nanotechnology Co., Ltd., with a specification of 500 nm; 2,5-Dimethylthiophene: purchased from Zhengzhou Anmusi Chemical Products Co., Ltd. Ferric chloride: purchased from Shandong West Asia Chemical Co., Ltd. Epoxy resin: purchased from Jinan Chuangshi Chemical Co., Ltd. Polycarbonate: purchased from Shanghai MacLean Biochemical Technology Co., Ltd. Nano-montmorillonite: purchased from Beijing Mairuida Technology Co., Ltd., with a specific surface area of 240 m 2 / g; Hexadecyltrimethylammonium bromide: purchased from Shanghai Aidie Industrial Co., Ltd. Light stabilizer 791: purchased from Beijing Tiangang Additive Co., Ltd. Light stabilizer 944: purchased from Beijing Tiangang Additive Co., Ltd.; Light stabilizer 783: purchased from Beijing Tiangang Additive Co., Ltd.; Polyoxyethylene alkyl ether: purchased from Shanghai Yuanye Biotechnology Co., Ltd.

[0020] Example 1

[0021] A method for preparing a high-performance modified antistatic composite material, the specific steps of the preparation method are as follows: S1-1: 15 parts by weight of carbon fiber was immersed in 100 parts by weight of a 7 M nitric acid solution, and ultrasonically treated at 70°C for 1.5 h at a frequency of 5.5 kHz and a power of 250 W. The carbon fiber was then washed with deionized water and vacuum dried at 60°C for 12 h to obtain carbon fiber A. S1-2: 10 parts by weight of carbon fiber A were added to 50 parts by weight of a 0.15 M 2,5-dimethylthiophene solution, and a 0.3 M ferric chloride solution was added dropwise at a rate of 1.5 mL / min, wherein the molar ratio of ferric chloride to 2,5-dimethylthiophene was 2:1. The mixture was stirred at 30°C for 6 h, washed with methanol and deionized water, and dried in vacuo at 60°C for 12 h to obtain modified carbon fiber; S1-3: 70 parts by weight of epoxy resin and 30 parts by weight of polycarbonate were mixed, 4 parts by weight of modified nano-montmorillonite and 1 part by weight of light stabilizer 944 were added, wherein the modified nano-montmorillonite was nano-montmorillonite modified with 2 wt% of hexadecyltrimethylammonium bromide, and the mixture was dispersed at 60°C and 1500 rpm for 30 min to obtain a matrix material; S1-4: 7 parts by weight of modified carbon fiber and 93 parts by weight of matrix material were mixed for 15 minutes, 1.5 parts by weight of polyoxyethylene alkyl ether solution was added, the mass fraction of the polyoxyethylene alkyl ether solution was 7%, the solvent was acetone, the temperature was 160 ° C, the speed was 700 rpm, and the high-performance modified antistatic composite material was obtained by extrusion molding through a twin-screw extruder.

[0022] Example 2

[0023] A method for preparing a high-performance modified antistatic composite material, the specific steps of the preparation method are as follows: S1-1: 10 parts by weight of carbon fiber were immersed in 100 parts by weight of a 6 M nitric acid solution, and ultrasonically treated at 60°C for 1 h at a frequency of 5 kHz and a power of 200 W. The carbon fiber was then washed with deionized water and vacuum dried at 60°C for 12 h to obtain carbon fiber A. S1-2: 5 parts by weight of carbon fiber A were added to 50 parts by weight of a 0.1 M 2,5-dimethylthiophene solution, and a 0.2 M ferric chloride solution was added dropwise at a rate of 1 mL / min, wherein the molar ratio of ferric chloride to 2,5-dimethylthiophene was 2:1. The mixture was stirred at 25°C for 4 hours, washed with methanol and deionized water, and dried in vacuo at 60°C for 12 hours to obtain modified carbon fiber; S1-3: 60 parts by weight of epoxy resin and 20 parts by weight of polycarbonate were mixed, 3 parts by weight of modified nano-montmorillonite and 0.5 parts by weight of light stabilizer 791 were added, wherein the modified nano-montmorillonite was nano-montmorillonite modified with 1 wt% of hexadecyltrimethylammonium bromide, and the mixture was dispersed at 55° C. and 1000 rpm for 20 min to obtain a matrix material; S1-4: 5 parts by weight of modified carbon fiber and 95 parts by weight of matrix material were mixed for 10 min, 1 part by weight of polyoxyethylene alkyl ether solution was added, the mass fraction of the polyoxyethylene alkyl ether solution was 5%, the solvent was acetone, the temperature was 150 ° C, the speed was 650 rpm, and the high-performance modified antistatic composite material was obtained by extrusion molding through a twin-screw extruder.

[0024] Example 3

[0025] A method for preparing a high-performance modified antistatic composite material, the specific steps of the preparation method are as follows: S1-1: 20 parts by weight of carbon fiber were immersed in 100 parts by weight of 8 M nitric acid solution, and ultrasonically treated at 80°C for 2 h at a frequency of 6 kHz and a power of 300 W. The carbon fiber was then washed with deionized water and vacuum dried at 60°C for 12 h to obtain carbon fiber A. S1-2: 15 parts by weight of carbon fiber A were added to 50 parts by weight of a 0.2 M 2,5-dimethylthiophene solution, and a 0.4 M ferric chloride solution was added dropwise at a rate of 2 mL / min, wherein the molar ratio of ferric chloride to 2,5-dimethylthiophene was 2:1. The mixture was stirred at 35°C for 8 hours, washed with methanol and deionized water, and dried in vacuo at 60°C for 12 hours to obtain modified carbon fiber; S1-3: 80 parts by weight of epoxy resin and 40 parts by weight of polycarbonate were mixed, 5 parts by weight of modified nano-montmorillonite and 1.5 parts by weight of light stabilizer 944 were added, wherein the modified nano-montmorillonite was nano-montmorillonite modified with 3 wt% of hexadecyltrimethylammonium bromide, and the mixture was dispersed at 65° C. and 2000 rpm for 40 min to obtain a matrix material; S1-4: 10 parts by weight of modified carbon fiber and 90 parts by weight of matrix material were mixed for 20 min, 2 parts by weight of polyoxyethylene alkyl ether solution was added, the mass fraction of the polyoxyethylene alkyl ether solution was 10%, the solvent was acetone, the temperature was 170 ° C, the speed was 750 rpm, and the high-performance modified antistatic composite material was obtained by extrusion molding through a twin-screw extruder.

[0026] Comparative Example 1

[0027] Without adding 2,5-dimethylthiophene, the remaining steps were the same as those in Example 1.

[0028] Comparative Example 2

[0029] Without adding polyoxyethylene alkyl ether, the remaining steps were the same as those in Example 1.

[0030] Comparative Example 3

[0031] The remaining steps were the same as those in Example 1 except that step S1-1 was omitted.

[0032] Comparative Example 4

[0033] Unmodified carbon fiber was used instead of the modified carbon fiber, and the remaining steps were the same as those in Example 1.

[0034] Performance Testing

[0035] The surface resistivity of the antistatic composite materials prepared in the examples and comparative examples was tested using an AS982 surface resistivity tester. The test temperature was 25°C and the humidity was 50% RH. The test was repeated three times for each group of samples and the average value was taken. The experimental results are shown in the following table.

[0036]

[0037] It can be seen from the data of the examples and comparative examples that the composite material prepared in the present invention has an excellent antistatic effect.

[0038] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a high-performance modified antistatic composite material, characterized in that: The specific steps of the preparation method are as follows: S1-1: 10 to 20 parts by weight of carbon fiber were immersed in 100 parts by weight of a 6 to 8 M nitric acid solution, ultrasonically treated at 60 to 80°C for 1 to 2 hours, washed with deionized water, and vacuum dried at 60°C for 12 hours to obtain carbon fiber A; S1-2: Add 5 to 15 parts by weight of carbon fiber A to 50 parts by weight of a 0.1 to 0.2 M 2,5-dimethylthiophene solution, add dropwise a 0.2 to 0.4 M ferric chloride solution, stir at 25 to 35 ° C for 4 to 8 hours, then wash with methanol and deionized water, and place under vacuum drying at 60 ° C for 12 hours to obtain modified carbon fiber; S1-3: 60-80 parts by weight of epoxy resin and 20-40 parts by weight of polycarbonate are mixed, 3-5 parts by weight of modified nano-montmorillonite and 0.5-1.5 parts by weight of hindered amine light stabilizer are added, and the mixture is dispersed at 55-65° C. for 20-40 minutes to obtain a matrix material; S1-4: Mix 5 to 10 parts by weight of modified carbon fiber with 90 to 95 parts by weight of matrix material for 10 to 20 minutes, add 1 to 2 parts by weight of polyoxyethylene alkyl ether solution, and extrude the mixture through a twin-screw extruder at a temperature of 150 to 170°C and a rotation speed of 650 to 750 rpm to obtain the high-performance modified antistatic composite material.

2. The method for preparing a high-performance modified antistatic composite material according to claim 1, wherein: The frequency of the ultrasonic treatment in S1-1 is 5 to 6 kHz, and the power of the ultrasonic treatment is 200 to 300 W.

3. The method for preparing a high-performance modified antistatic composite material according to claim 1, characterized in that: The dropping speed of the ferric chloride solution in S1-2 is 1-2 mL / min.

4. The method for preparing a high-performance modified antistatic composite material according to claim 1, wherein: The molar ratio of ferric chloride to 2,5-dimethylthiophene in S1-2 is 2:

1.

5. The method for preparing a high-performance modified antistatic composite material according to claim 1, characterized in that: The dispersion speed in S1-3 is 1000-2000 rpm.

6. The method for preparing a high-performance modified antistatic composite material according to claim 1, characterized in that: The hindered amine light stabilizer includes but is not limited to light stabilizer 791, light stabilizer 944, and light stabilizer 783.

7. The method for preparing a high-performance modified antistatic composite material according to claim 1, characterized in that: The modified nano-montmorillonite in S1-3 is nano-montmorillonite modified with 1-3 wt% of hexadecyltrimethylammonium bromide.

8. The method for preparing a high-performance modified antistatic composite material according to claim 1, characterized in that: The mass fraction of the polyoxyethylene alkyl ether solution in S1-4 is 5% to 10%, and the solvent is acetone.

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