A thermoplastic semiconductive shielding material for conductors and its preparation method

Abstract

This invention relates to the field of cable shielding materials, and discloses a thermoplastic semiconductive shielding material for conductors and its preparation method. The thermoplastic semiconductive shielding material for conductors of this invention comprises the following components in parts by weight: 100g of EVA resin and 35-70g of carbon black-polypyrrole-graphene conductive filler. The conductive carbon black is grafted with polypyrrole polymer, which helps reduce carbon black agglomeration, improves its dispersibility in EVA resin, and enhances conductivity. Sulfonated graphene contains sulfonic acid groups, which interact with the pyrrole nitrogen of polypyrrole, enhancing the interfacial properties between graphene and carbon black particles, allowing graphene to tightly fill the gaps between carbon black particles, forming a continuous conductive network. As a conductive polymer, polypyrrole can promote electron migration between carbon black and graphene, improving the conductivity of the carbon black-polypyrrole-graphene conductive filler and reducing the volume resistivity of the EVA shielding material.

Description

Technical Field

[0001] This invention relates to the field of cable shielding materials, specifically to a thermoplastic semiconductive shielding material for conductors and its preparation method. Background Technology

[0002] Cable shielding material is a functional material that covers the outside of cable conductors to uniformly distribute the electric field, suppress partial discharge, and block electromagnetic interference. It is mainly composed of base resins such as polyethylene and EVA, as well as conductive fillers such as conductive carbon black. It adheres tightly to the conductor, is at the same potential as the conductor, and does not short-circuit. It smooths out the uneven gaps in the stranded conductor, thereby eliminating the concentration of electric field in the air gap and preventing partial discharge.

[0003] Traditional conductive carbon black requires a large dosage, exhibits poor dispersibility in matrix resins such as EVA, struggles to form continuous conductive pathways, and significantly impacts the mechanical properties of shielding materials. High-performance carbon nanomaterials for shielding materials can improve their semi-conductivity and mechanical properties. Graphene, in particular, possesses strong conductivity, high mechanical strength, and good heat resistance, making it widely used in cables and other applications. Surface modification of graphene can address its agglomeration problem and improve its compatibility with the resin matrix, thereby further enhancing the material's conductivity and other properties. Summary of the Invention

[0004] The technical problem solved by this invention is to address the issues of high resistance, poor conductivity, and unsatisfactory mechanical properties of EVA shielding material.

[0005] Technical solution: A thermoplastic semiconductive shielding material for conductors, comprising the following components in parts by weight: 100g of EVA resin, 0.4-0.7 parts of antioxidant, 4-8 parts of lubricant, and 35-70 parts of carbon black-polypyrrole-graphene conductive filler.

[0006] Preferably, the antioxidant is any one or a combination of antioxidant 1010, antioxidant 1076, and antioxidant 300.

[0007] Preferably, the lubricant is any one or a combination of stearic acid, paraffin wax, and polyethylene wax.

[0008] Preferably, the preparation method of the thermoplastic semiconductive shielding material for conductors is as follows: (1) Add 100 parts of graphene oxide to water by weight, disperse by ultrasonication for 20-30 min, add 700-1500 parts of sodium 2-chloroethylsulfonate and 170-360 parts of sodium hydroxide, heat to 30-40℃, continue ultrasonication for 2-5 h, add concentrated nitric acid to adjust pH to 4-5, filter, wash with water, and dry to obtain sulfonated graphene.

[0009] (2) Add 100 parts pyrrole and 155-179 parts sodium hydroxide to tetrahydrofuran by weight, stir, add 290-296 parts 3-chloropropyltrimethoxysilane, heat to 40-60℃, stir for 2-3 hours, filter, evaporate the solution by rotary evaporation, and separate the product by column chromatography to obtain 3-pyrrolepropyltrimethoxysilane.

[0010] (3) Add water and 2-6 parts of 3-pyrrolopropyltrimethoxysilane to ethanol by weight, stir for 15-20 min, add 100 parts of conductive carbon black, ethanol and water, sonicate for 20-30 min, heat to 50-70℃, stir for 1.5-3 h, filter, wash with ethanol and water, dry to obtain pyrrolocarbon black.

[0011] (4) Add 100 parts by weight of pyrrole carbon black and 8-30 parts by weight of pyrrole to water, stir and disperse in an ice-water bath, then add dropwise an aqueous solution containing 11-42 parts by weight of ferric chloride, stir and react for 6-8 hours, add 3-10 parts by weight of sulfonated graphene, stir and mix at 15-30°C for 1-3 hours, add 20-77 parts by weight of p-toluenesulfonic acid, stir and filter, wash with water and ethanol, and dry to obtain carbon black-polypyrrole-graphene conductive filler.

[0012] (5) EVA resin, antioxidant, lubricant, carbon black-polypyrrole-graphene conductive filler are mixed in a mixer and then melt-blended in a screw extruder at a temperature of 150-200℃ in each zone. After extrusion, the mixture is granulated to obtain a thermoplastic semiconductive shielding material for conductors.

[0013] Beneficial technical effects: Surface modification with 3-pyrrolopropyltrimethoxysilane introduces pyrrole structure as an in-situ polymerization site, and oxidative polymerization with pyrrole monomers to obtain polypyrrole grafted carbon black. Then, it is mixed with sulfonated graphene to obtain carbon black-polypyrrole-graphene conductive filler. When added to EVA resin, it yields thermoplastic semiconductive shielding material for conductors.

[0014] The conductive carbon black of the present invention is grafted with polypyrrole polymer. The polymer molecular chains form steric hindrance on the surface of the carbon black, which helps to reduce the agglomeration of carbon black, improve its dispersibility in EVA resin, improve conductivity, and maintain good tensile strength and elongation at break of the shielding material, resulting in good mechanical properties.

[0015] The sulfonated graphene of the present invention contains sulfonic acid groups, which interact with the pyrrole nitrogen of polypyrrole to enhance the interfacial properties between graphene and carbon black particles, allowing graphene to tightly fill the gaps between carbon black particles, forming a continuous conductive network, and further reducing the resistivity of EVA resin.

[0016] The polypyrrole of this invention, as a conductive polymer, can promote the migration of electrons between carbon black and graphene, improve the conductivity of carbon black-polypyrrole-graphene conductive filler, and significantly reduce the volume resistivity of EVA shielding material. Detailed Implementation

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] EVA resin, model number Hanwha 1533 (Korea), manufactured by Ningbo Rongsu New Materials. Conductive carbon black, model number VXC72R, manufactured by Hubei Xingdongcheng Chemical. Graphene oxide, with an effective ingredient content of 99.99%, manufactured by Shanghai Yanbei New Materials Technology.

[0019] Example 1: (1) Add 1 part by weight of graphene oxide to 800 parts by weight of water, sonicate for 30 min, add 10 parts by weight of sodium 2-chloroethylsulfonate and 2.4 parts by weight of sodium hydroxide, heat to 40°C, continue sonication for 3 h, add concentrated nitric acid to adjust pH to 4, filter, wash with water, and dry to obtain sulfonated graphene.

[0020] (2) Add 100 parts by weight of pyrrole and 164 parts by weight of sodium hydroxide to 3000 parts by weight of tetrahydrofuran, stir, then add 296 parts by weight of 3-chloropropyltrimethoxysilane, heat to 40°C, stir for 3 hours, filter, and then evaporate the solution by rotary evaporation. Separate the product by column chromatography to obtain 3-pyrrolepropyltrimethoxysilane. The reaction formula is: .

[0021] (3) Add 2 parts of water and 4.5 parts of 3-pyrrolopropyltrimethoxysilane to 20 parts of ethanol, stir for 20 min, add 100 parts of conductive carbon black, 3500 parts of ethanol and 900 parts of water, sonicate for 30 min, heat to 70°C, stir and reflux for 1.5 h, filter, wash with ethanol and water, dry to obtain pyrrolocarbon black.

[0022] (4) Add 100 parts by weight of pyrrole-based carbon black and 8 parts by weight of pyrrole to 5000 parts by weight of water, stir and disperse in an ice-water bath for 20 min, then add dropwise an aqueous solution containing 11 parts by weight of ferric chloride (total weight 90 parts by weight), stir and react for 6 h, add 3 parts by weight of sulfonated graphene, stir and mix at 20 °C for 1 h, add 20 parts by weight of p-toluenesulfonic acid, stir for 2 h, filter, wash with water and ethanol after filtration, and dry to obtain carbon black-polypyrrole-graphene conductive filler.

[0023] (5) Mix 100 parts by weight of EVA resin, 0.5 parts by weight of antioxidant 1010, 2.7 parts by weight of stearic acid, 4.2 parts by weight of paraffin wax, and 35 parts by weight of carbon black-polypyrrole-graphene conductive filler in a mixer, and then melt-blend in a screw extruder at temperatures of 150°C, 185°C, 200°C, 200°C, and 195°C. After extrusion, granulate to obtain thermoplastic semiconductive shielding material for conductors.

[0024] Example 2: (1) Add 1 part by weight of graphene oxide to 800 parts by weight of water, sonicate for 30 min, add 7 parts by weight of sodium 2-chloroethylsulfonate and 1.7 parts by weight of sodium hydroxide, heat to 40°C, continue sonication for 2 h, add concentrated nitric acid to adjust pH to 4, filter, wash with water, and dry to obtain sulfonated graphene.

[0025] (2) Add 100 parts by weight of pyrrole and 179 parts by weight of sodium hydroxide to 3000 parts by weight of tetrahydrofuran, stir, add 290 parts by weight of 3-chloropropyltrimethoxysilane, heat to 50°C, stir and reflux for 3 hours, filter, evaporate the solution by rotary evaporation, and separate the product by column chromatography to obtain 3-pyrrolepropyltrimethoxysilane.

[0026] (3) Add 3 parts of water and 6 parts of 3-pyrrolopropyltrimethoxysilane to 25 parts of ethanol, stir for 15 min, add 100 parts of conductive carbon black, 4000 parts of ethanol and 1000 parts of water, sonicate for 30 min, heat to 50°C, stir, reflux and cool for 3 h, filter, wash with ethanol and water, dry to obtain pyrrolocarbon black.

[0027] (4) Add 100 parts by weight of pyrrole-based carbon black and 15 parts by weight of pyrrole to 6000 parts by weight of water, stir and disperse in an ice-water bath for 20 min, then add dropwise an aqueous solution containing 22 parts by weight of ferric chloride (total weight 150 parts by weight), stir and react for 6 h, add 5 parts by weight of sulfonated graphene, stir and mix at 20 °C for 3 h, add 30 parts by weight of p-toluenesulfonic acid, stir for 3 h, filter, wash with water and ethanol after filtration, and dry to obtain carbon black-polypyrrole-graphene conductive filler.

[0028] (5) Mix 100 parts by weight of EVA resin, 0.6 parts by weight of antioxidant 1076, 3.8 parts by weight of stearic acid, 4.2 parts by weight of paraffin wax, and 45 parts by weight of carbon black-polypyrrole-graphene conductive filler in a mixer, and then melt-blend in a screw extruder at temperatures of 150°C, 185°C, 200°C, 200°C, and 195°C. After extrusion, granulate to obtain thermoplastic semiconductive shielding material for conductors.

[0029] Example 3: (1) Add 1 part by weight of graphene oxide to 1000 parts by weight of water, sonicate for 20 min, add 15 parts by weight of sodium 2-chloroethylsulfonate and 3.6 parts by weight of sodium hydroxide, heat to 30°C, continue sonication for 5 h, add concentrated nitric acid to adjust pH to 5, filter, wash with water, and dry to obtain sulfonated graphene.

[0030] (2) Add 100 parts by weight of pyrrole and 155 parts by weight of sodium hydroxide to 3000 parts by weight of tetrahydrofuran, stir, add 296 parts by weight of 3-chloropropyltrimethoxysilane, heat to 60°C, stir and reflux for 2 hours, filter, evaporate the solution by rotary evaporation, and separate the product by column chromatography to obtain 3-pyrrolepropyltrimethoxysilane.

[0031] (3) Add 1 part water and 2 parts 3-pyrrolopropyltrimethoxysilane to 8 parts ethanol by weight, stir for 15 min, add 100 parts conductive carbon black, 3800 parts ethanol and 1000 parts water by weight, sonicate for 20 min, heat to 70°C, stir and reflux for 2 h, filter, wash with ethanol and water, dry to obtain pyrrolocarbon black.

[0032] (4) Add 100 parts by weight of pyrrole carbon black and 30 parts by weight of pyrrole to 7000 parts by weight of water, stir and disperse in an ice-water bath for 30 min, then add dropwise an aqueous solution containing 42 parts by weight of ferric chloride (total weight 350 parts by weight), stir and react for 8 h, add 10 parts by weight of sulfonated graphene, stir and mix at 20 °C for 3 h, add 77 parts by weight of p-toluenesulfonic acid, stir for 3 h, filter, wash with water and ethanol after filtration, and dry to obtain carbon black-polypyrrole-graphene conductive filler.

[0033] (5) Mix 100 parts by weight of EVA resin, 0.4 parts by weight of antioxidant 1010, 2.6 parts by weight of stearic acid, 1.4 parts by weight of polyethylene wax and 55 parts by weight of carbon black-polypyrrole-graphene conductive filler in a mixer, and then melt-blend in a screw extruder at temperatures of 150°C, 185°C, 200°C, 200°C and 195°C. After extrusion, granulate to obtain thermoplastic semiconductive shielding material for conductors.

[0034] Example 4: (1) Add 1 part by weight of graphene oxide to 900 parts by weight of water, sonicate for 20 min, add 12 parts by weight of sodium 2-chloroethylsulfonate and 2.9 parts by weight of sodium hydroxide, heat to 30°C, continue sonication for 5 h, add concentrated nitric acid to adjust pH to 4, filter, wash with water, and dry to obtain sulfonated graphene.

[0035] (2) Add 100 parts by weight of pyrrole and 164 parts by weight of sodium hydroxide to 3000 parts by weight of tetrahydrofuran, stir, add 296 parts by weight of 3-chloropropyltrimethoxysilane, heat to 50°C, stir for 3 hours, filter, evaporate the solution by rotary evaporation, and separate the product by column chromatography to obtain 3-pyrrolepropyltrimethoxysilane.

[0036] (3) Add 2 parts of water and 3.5 parts of 3-pyrrolopropyltrimethoxysilane to 15 parts of ethanol, stir for 20 min, add 100 parts of conductive carbon black, 4000 parts of ethanol and 1000 parts of water, sonicate for 20 min, heat to 60°C, stir, reflux and cool for 3 h, filter, wash with ethanol and water, dry to obtain pyrrolocarbon black.

[0037] (4) Add 100 parts by weight of pyrrole-based carbon black and 22 parts by weight of pyrrole to 6000 parts by weight of water, stir and disperse in an ice-water bath for 30 min, then add dropwise an aqueous solution containing 32 parts by weight of ferric chloride (total weight 270 parts by weight), stir and react for 6 h, add 7.5 parts by weight of sulfonated graphene, stir and mix at 25 °C for 2 h, add 58 parts by weight of p-toluenesulfonic acid, stir for 2 h, filter, wash with water and ethanol after filtration, and dry to obtain carbon black-polypyrrole-graphene conductive filler.

[0038] (5) 100 parts by weight of EVA resin, 0.7 parts by weight of antioxidant 300, 3.2 parts by weight of stearic acid, 4.4 parts by weight of paraffin wax and 70 parts by weight of carbon black-polypyrrole-graphene conductive filler are mixed in a mixer and then melt-blended in a screw extruder at temperatures of 150°C, 185°C, 200°C, 200°C and 195°C. After extrusion, the mixture is granulated to obtain a thermoplastic semiconductive shielding material for conductors.

[0039] Comparative Example 1 differs from Example 1 in that graphene oxide is used instead of sulfonated graphene.

[0040] (1) Add 100 parts by weight of pyrrole-based carbon black and 8 parts by weight of pyrrole to 5000 parts by weight of water, stir and disperse in an ice-water bath for 20 min, then add dropwise an aqueous solution containing 11 parts by weight of ferric chloride (total weight 90 parts by weight), stir and react for 6 h, add 3 parts by weight of graphene oxide, stir and mix at 20 °C for 1 h, add 20 parts by weight of p-toluenesulfonic acid, stir for 2 h, filter, wash with water and ethanol after filtration, and dry to obtain carbon black-polypyrrole-graphene conductive filler.

[0041] (2) 100 parts by weight of EVA resin, 0.5 parts by weight of antioxidant 1010, 2.7 parts by weight of stearic acid, 4.2 parts by weight of paraffin wax, and 35 parts by weight of carbon black-polypyrrole-graphene conductive filler are mixed in a mixer and then melt-blended in a screw extruder at temperatures of 150°C, 185°C, 200°C, 200°C, and 195°C. After extrusion, the mixture is granulated to obtain a thermoplastic semiconductive shielding material for conductors.

[0042] Comparative Example 2 differs from Example 1 in that it does not use polypyrrole-grafted carbon black.

[0043] (1) Add 100 parts by weight of pyrrole carbon black and 3 parts by weight of sulfonated graphene to 5000 parts by weight of water, stir and mix at 20°C for 1 hour, add 20 parts by weight of p-toluenesulfonic acid, stir for 2 hours, filter, wash with water and ethanol after filtration, and dry to obtain carbon black-graphene conductive filler.

[0044] (2) 100 parts by weight of EVA resin, 0.5 parts by weight of antioxidant 1010, 2.7 parts by weight of stearic acid, 4.2 parts by weight of paraffin wax and 35 parts by weight of carbon black-graphene conductive filler are mixed in a mixer and then melt-blended in a screw extruder at temperatures of 150°C, 185°C, 200°C, 200°C and 195°C. After extrusion, the mixture is granulated to obtain a thermoplastic semiconductive shielding material for conductors.

[0045] Comparative Example 3 differs from Example 1 in that 3-chloropropyltrimethoxysilane is used instead of 3-pyrrolopropyltrimethoxysilane.

[0046] (1) Add 2 parts by weight of water and 4.5 parts by weight of 3-chloropropyltrimethoxysilane to 20 parts by weight of ethanol, stir for 20 min, add 100 parts by weight of conductive carbon black, 3500 parts by weight of ethanol and 900 parts by weight of water, sonicate for 30 min, heat to 70°C, stir and reflux for 1.5 h, filter, wash with ethanol and water, dry to obtain modified carbon black.

[0047] (2) Add 100 parts by weight of modified carbon black and 8 parts by weight of pyrrole to 5000 parts by weight of water, stir and disperse in an ice-water bath for 20 min, then add dropwise an aqueous solution containing 11 parts by weight of ferric chloride (total weight 90 parts by weight), stir and react for 6 h, add 3 parts by weight of sulfonated graphene, stir and mix at 20 °C for 1 h, add 20 parts by weight of p-toluenesulfonic acid, stir for 2 h, filter, wash with water and ethanol after filtration, and dry to obtain carbon black-polypyrrole-graphene conductive filler.

[0048] (3) 100 parts by weight of EVA resin, 0.5 parts by weight of antioxidant 1010, 2.7 parts by weight of stearic acid, 4.2 parts by weight of paraffin wax, and 35 parts by weight of carbon black-polypyrrole-graphene conductive filler are mixed in a mixer and then melt-blended in a screw extruder at temperatures of 150°C, 185°C, 200°C, 200°C, and 195°C. After extrusion, the mixture is granulated to obtain a thermoplastic semiconductive shielding material for conductors.

[0049] The conductor is molded in a flat vulcanizing machine at 185°C for 10 minutes under a pressure of 10 MPa using thermoplastic semiconducting shielding material, and then cut into test strips.

[0050] Volume resistivity was tested according to the method in standard GB / T 3048.3-2007, and tensile properties were tested according to the method in standard GB / T 1040.1-2025. The test results are shown in the table below.

[0051] The thermoplastic semiconductive shielding materials in Examples 1-4 exhibit lower volume resistivity and good tensile strength and elongation at break, primarily due to the addition of carbon black-polypyrrole-graphene conductive filler. The conductive carbon black is grafted with polypyrrole polymer, and the polymer molecular chains create steric hindrance on the carbon black surface, which helps reduce carbon black agglomeration, improves its dispersibility in EVA resin, enhances conductivity, and maintains good mechanical properties. Simultaneously, sulfonated graphene contains sulfonic acid groups, which interact with the pyrrole nitrogen in polypyrrole, enhancing the interfacial properties between graphene and carbon black particles. This allows graphene to tightly fill the gaps between carbon black particles, forming a continuous conductive network, further reducing the resistivity of EVA resin. Furthermore, polypyrrole, as a conductive polymer, promotes electron migration between carbon black and graphene, improving the conductivity of the carbon black-polypyrrole-graphene conductive filler, significantly reducing the volume resistivity of the EVA shielding material, and resulting in high tensile strength and elongation at break, as well as good mechanical properties.

[0052] The graphene oxide in Comparative Example 1 does not contain a sulfonic acid matrix, resulting in poor interfacial properties with the polypyrrole-grafted carbon black. The graphene does not fill the gaps between the carbon black particles well, making it difficult to form a continuous conductive network. Consequently, the EVA shielding material has a high volume resistivity.

[0053] Comparative Example 2 did not utilize polypyrrole-grafted carbon black, resulting in poor interfacial properties between sulfonated graphene and carbon black. Furthermore, it did not contain polypyrrole conductive molecular chains, leading to poor conductivity of the carbon black-graphene conductive filler and a high volume resistivity of the EVA shielding material.

[0054] Comparative Example 3 uses 3-chloropropyltrimethoxysilane to modify carbon black, resulting in the absence of pyrrole structures on the carbon black surface. This prevents the carbon black from undergoing in-situ graft polymerization with pyrrole monomers. The resulting polypyrrole has poor reactivity with the chlorine atoms of the modified carbon black, which means that the polypyrrole is not well grafted onto the carbon black surface. This is not conducive to reducing the agglomeration of carbon black and results in a higher volume resistivity of the EVA shielding material.

Claims

1. A thermoplastic semiconductive shielding material for conductors, characterized in that, The thermoplastic semiconductive shielding material for conductors comprises the following components in parts by weight: 100g of EVA resin, 0.4-0.7 parts of antioxidant, 4-8 parts of lubricant, and 35-70 parts of carbon black-polypyrrole-graphene conductive filler.

2. The thermoplastic semiconductive shielding material for conductors according to claim 1, characterized in that, The antioxidant is any one or a combination of antioxidant 1010, antioxidant 1076, and antioxidant 300.

3. The thermoplastic semiconductive shielding material for conductors according to claim 1, characterized in that, The lubricant is any one or a combination of stearic acid, paraffin wax, and polyethylene wax.

4. The thermoplastic semiconductive shielding material for conductors according to claim 1, characterized in that, The carbon black-polypyrrole-graphene conductive filler is prepared by the following method: (1) Add water and 2-6 parts of 3-pyrrolopropyltrimethoxysilane to ethanol by weight, stir, add 100 parts of conductive carbon black, ethanol and water, disperse by ultrasonication, stir and react, filter, wash and dry to obtain pyrrolocarbon black. (2) Add 100 parts by weight of pyrrole carbon black and 8-30 parts by weight of pyrrole to water, stir and disperse in an ice-water bath, then add dropwise an aqueous solution containing 11-42 parts by weight of ferric chloride to react, add 3-10 parts by weight of sulfonated graphene, stir and mix, add 20-77 parts by weight of p-toluenesulfonic acid, stir, filter, wash, and dry to obtain carbon black-polypyrrole-graphene conductive filler.

5. The thermoplastic semiconductive shielding material for conductors according to claim 1, characterized in that, The reaction temperature in (1) is 50-70℃ and the reaction time is 1.5-3h.

6. The thermoplastic semiconductive shielding material for conductors according to claim 1, characterized in that, The reaction time in (2) is 6-8h; the temperature during stirring and mixing is 15-30℃ and the time is 1-3h.

7. The thermoplastic semiconductive shielding material for conductors according to claim 4, characterized in that, The 3-pyrrolopropyltrimethoxysilane was prepared as follows: 100 parts by weight of pyrrole and 155-179 parts by weight of sodium hydroxide were added to tetrahydrofuran, and after stirring, 290-296 parts by weight of 3-chloropropyltrimethoxysilane were added. The mixture was heated to 40-60°C and stirred for 2-3 hours. After filtration, the solution was evaporated by rotary evaporation, and the product was separated by column chromatography to obtain 3-pyrrolopropyltrimethoxysilane.

8. The thermoplastic semiconductive shielding material for conductors according to claim 4, characterized in that, The sulfonated graphene is prepared by the following method: 100 parts by weight of graphene oxide are added to water, ultrasonically dispersed, 700-1500 parts of sodium 2-chloroethylsulfonate and 170-360 parts of sodium hydroxide are added, heated to 30-40℃, ultrasonically continued for 2-5 hours, nitric acid is added dropwise to adjust the pH to 4-5, filtered, washed, and dried to obtain sulfonated graphene.

9. A method for preparing a thermoplastic semiconductive shielding material for conductors as described in any one of claims 1-8, characterized in that, The preparation method is as follows: EVA resin, antioxidant, lubricant, carbon black-polypyrrole-graphene conductive filler are mixed in a mixer, and then melt-blended in a screw extruder at a temperature of 150-200℃ in each zone. After extrusion, the mixture is granulated to obtain a thermoplastic semiconductive shielding material for conductors.

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