Carbon nano composite conductive material and application thereof in cable shielding layer

Abstract

The invention discloses a carbon nano composite conductive material and application thereof in a cable shielding layer, and belongs to the technical field of conductive shielding materials, the carbon nano composite conductive material comprises 20-35 parts of magnetic iron / PEDOT: PSS nanoparticles and 40-65 parts of a carbon nano material; the magnetic iron / PEDOT: PSS nanoparticles are obtained by modifying the surfaces of magnetic iron nanoparticles with 3, 4-ethylenedioxythiophene: poly (styrene sulfonic acid); the carbon nanomaterial is one or more of carbon black, graphene oxide, reduced graphene oxide and a carbon nanotube. The carbon material is used as the conductive material, and the magnetic iron / PEDOT: PSS nanoparticles are added to replace part of the conductive filler, so that the cable has the advantages of strong anti-interference capability, light weight, high strength and good flexibility.

Description

Technical Field

[0001] The invention belongs to the technical field of conductive shielding materials, and in particular relates to a carbon nanocomposite conductive material and an application thereof in a cable shielding layer. Background Art

[0002] Monitoring medical devices are mainly used for clinical monitoring. They monitor the patient's heart rate, blood pressure, blood oxygen, fetal heart rate, breathing and other physiological parameters in real time. They can reflect the patient's vital signs in real time and assist medical staff in observing the patient's physical condition. If functional failure or malfunction occurs during use, it will cause monitoring failure and even mislead medical staff's diagnosis and treatment. Monitoring medical devices generally transmit small signals. When the frequency is low, the wavelength is generally much larger than the length of the holes in the casing. It is difficult for electromagnetic waves in space to pass through the holes in the metal casing. However, the external cables of the equipment, such as power cables, signal cables, and ground cables, may be several wavelengths of the interference wave in length. These cables act as receiving antennas, receiving interference electromagnetic waves in space, inducing interference voltage or current, and coupling them into the equipment in a common-mode conduction manner.

[0003] Common cable structures include conductors, insulation layers, shielding layers and outer sheaths, among which the shielding layer can effectively block electromagnetic interference. Traditional electromagnetic shielding materials are metal materials, which are hard electromagnetic shielding materials. They mainly use the electrical conductivity and magnetism of the metal itself to reflect, absorb and attenuate electromagnetic waves. Among them, conductive metals include metal silver and copper, and magnetic metal materials include pure iron, iron-nickel alloys, etc. However, one of the main disadvantages of metal electromagnetic shielding materials is their heavy weight. In addition, metals have high rigidity and are not easy to adapt to flexible surfaces or bends, which limits their application in monitoring medical device cables. In recent years, many novel electromagnetic shielding materials have emerged, including filling materials such as conductive rubber, conductive foam, conductive adhesives, etc., as well as surface-plated electromagnetic shielding materials such as conductive fabrics. The emergence of these materials has greatly expanded the application scenarios of electromagnetic shielding technology in various fields. Carbon nanomaterials have excellent electromagnetic shielding properties, excellent mechanical properties, good chemical stability and corrosion resistance, and are excellent filling materials for insulating layers. However, their shielding effect on interference caused by low-frequency magnetic fields is poor. Summary of the invention

[0004] In order to overcome the shortcomings of the above-mentioned prior art, the present invention provides a carbon nanocomposite conductive material, which uses carbon material as a conductive material and adds magnetic iron / PEDOT:PSS nanoparticles to replace part of the conductive filler, so that the cable has the advantages of strong anti-interference ability, light weight and good flexibility. The magnetic iron / PEDOT:PSS nanoparticles are grafted with conductive polymers on the surface of the magnetic iron nanoparticles, thereby improving the dispersibility, stability and conductivity of the magnetic iron nanoparticles. The magnetic core has excellent magnetic properties, and the outer layer is a conductive polymer, which can make the magnetic loss and dielectric loss achieve an electromagnetic synergistic state.

[0005] The technical scheme for achieving the purpose of the present invention is as follows: a carbon nanocomposite conductive material, comprising, by weight, 20 to 35 parts of magnetic iron / PEDOT:PSS nanoparticles and 40 to 65 parts of carbon nanomaterials; the magnetic iron / PEDOT:PSS nanoparticles are obtained by modifying the surface of magnetic iron nanoparticles with 3,4-ethylenedioxythiophene:poly(styrene sulfonic acid); the carbon nanomaterial is one or more of carbon black, graphene oxide, reduced graphene oxide and carbon nanotubes.

[0006] Preferably, the preparation method of the magnetic iron / PEDOT:PSS nanoparticles is as follows:

[0007] S1. The hydroxyl groups on the surface of the magnetic iron nanoparticles react with the halogenated acyl halide through an acylation reaction to obtain modified magnetic iron nanoparticles;

[0008] S2. The halogen atoms of the modified magnetic iron nanoparticles are used to initiate the polymerization of sodium 4-vinylbenzenesulfonate to obtain magnetic iron nanoparticles with surface grafted poly(styrenesulfonic acid), and then 3,4-ethylenedioxythiophene is polymerized by benzoyl oxide to obtain magnetic iron / PEDOT:PSS nanoparticles.

[0009] More preferably, the preparation method of the magnetic iron / PEDOT:PSS nanoparticles is as follows:

[0010] S1. The magnetic iron nanoparticles are dispersed in an anhydrous solvent by ultrasonication, and an acid binding agent is added under an inert atmosphere, and then the halogenated acyl halide is dissolved in an anhydrous solvent, and the mixture is slowly added dropwise to the mixture, and stirred at room temperature for 24 to 48 hours, centrifuged, and the solid product is collected and vacuum dried to obtain modified magnetic iron nanoparticles;

[0011] S2. Sodium 4-vinylbenzenesulfonate, chloride or bromide, and polar protic solvent are added to a reactor under stirring, and the modified magnetic iron nanoparticles obtained in step S1 are added together with a sodium hydroxide solution, and the pH is adjusted to 6-10. After freeze-thaw degassing, cuprous ions and ligand 2,2'-bipyridine are added, and the reaction is carried out at room temperature for 3-6 hours. After the reaction is completed, oxygen is introduced into the reaction system under ice bath conditions to terminate the polymerization reaction, and the pH is adjusted to 4-6. The solid product is centrifuged, collected and dispersed in water, and divided into two equal parts, benzoyl peroxide is added to one part, and 3,4-ethylenedioxythiophene is added to the other part. The two solutions are mixed and stirred continuously at room temperature for 16-48 hours. The resulting solution is post-treated to obtain magnetic iron / PEDOT:PSS nanoparticles.

[0012] Preferably, the magnetic iron nanoparticles are magnetic Fe3O4 nanoparticles, magnetic NiFe2O4 nanoparticles, magnetic CoFe2O4 nanoparticles, magnetic MnFe2O4 nanoparticles and magnetic BaFe 12 O 19 One or more nanoparticles.

[0013] Preferably, the magnetic iron nanoparticles are magnetic iron nanoparticles having hydroxyl groups on the surface;

[0014] Preferably, the magnetic iron nanoparticles are obtained by a hydrothermal method.

[0015] More preferably, the magnetic iron nanoparticles are magnetic NiFe2O4 nanoparticles.

[0016] Specifically, the preparation method of the magnetic NiFe2O4 nanoparticles is as follows:

[0017] Ferric nitrate and nickel nitrate are added to deionized water at room temperature, and then 4-5 mol / L sodium hydroxide solution is slowly added to adjust the pH to 9.5-10.5. After mechanical stirring for 0.5-1h, the solution is transferred to a steel autoclave lined with Teflon, sealed and heated at 110°C for 10-12h, and then naturally cooled to room temperature. The obtained solution is centrifuged, and the obtained particles are dried in an oven at 50-60°C for 10-12h, and then the above particles are placed in a muffle furnace, heated to 400°C at a heating rate of 2-5°C / min, maintained at 400°C for 2 hours, and then naturally cooled to room temperature to obtain magnetic NiFe2O4 nanoparticles.

[0018] Specifically, the molar ratio of the iron nitrate to the nickel nitrate is 2:1.

[0019] Preferably, in step S1, the halogenated acyl halide is one or more of 4-chloromethylbenzoyl chloride, 3-(chloromethyl)benzoyl chloride, 2-bromoisobutyryl bromide, 2-chloroisobutyryl chloride, chloroacetyl chloride and bromoacetyl bromide; the acid binding agent is at least one of triethylamine and pyridine; the solvent is one or more of dimethyl sulfoxide, dichloromethane and dimethylformamide; the mass ratio of the magnetic iron nanoparticles: acid binding agent: halogenated acyl halide is 1:(1.5-2):(0.5-1).

[0020] More preferably, in step S2, the chloride salt is at least one of potassium chloride and sodium chloride, and the bromide salt is at least one of sodium bromide and potassium bromide; the cuprous ion is at least one of cuprous bromide or cuprous chloride; the concentration of the sodium hydroxide solution is 1-2 mol / L; the mass ratio of the modified magnetic iron nanoparticles to sodium 4-vinylbenzenesulfonate is 1:(1.5-10); the molar ratio of the sodium 4-vinylbenzenesulfonate, cuprous ions, ligand 2,2'-bipyridine, chloride salt or bromide salt is (180-230):(0.5-1):(1-2):(0.05-10); the mass ratio of sodium 4-vinylbenzenesulfonate, 3,4-ethylenedioxythiophene and benzoyl peroxide is (2-5):1:(0.5-2); the polar protic solvent is at least one of water and methanol, water and ethanol, and the volume fraction of the alcohol in the solution is 0-50%.

[0021] Preferably, the post-treatment step in step S2 is to wash the obtained solution with chloroform at least twice, adjust the pH of the obtained aqueous solution to 6-8, centrifuge, and collect the solid product to obtain magnetic iron / PEDOT:PSS nanoparticles.

[0022] The invention also discloses application of the carbon nanocomposite conductive material in a cable shielding layer.

[0023] Preferably, the cable shielding layer comprises, by weight, 90-100 parts of rubber, 10-20 parts of reinforcing agent, 60-95 parts of carbon nanocomposite conductive material, 4-5 parts of silane coupling agent, 1-1.3 parts of antioxidant, 2-4 parts of vulcanizing agent, and 1-2 parts of accelerator; the cable shielding layer is prepared by the following steps:

[0024] (1) After the carbon nanocomposite conductive material is stirred and dispersed, a reinforcing agent and a coupling agent are poured into a vacuum kneader, and then the silicone rubber raw rubber is slowly added. During the mixing process, the carbon nanocomposite conductive material is added in batches, and the kneader vacuum valve and exhaust valve are closed before mixing. After the filler and the raw rubber are evenly mixed, the kneader is heated to 145-155° C. and mixed for 2-3 hours, and then vacuum kneaded at 115-125° C. for 1-2 hours, and then cooled to room temperature to obtain a silicone rubber masterbatch;

[0025] (2) Add antioxidant, vulcanizing agent and accelerator to silicone rubber masterbatch by double-roll mill, mix well and produce sheets, extrude them on cable insulation layer by extruder, and obtain cable shielding layer after vulcanization.

[0026] Preferably, the vulcanization conditions of the silicone rubber masterbatch in step (2) are a temperature of 160-185° C., 5-20 min, and a pressure of 1.5-2.5 MPa.

[0027] Beneficial Effects

[0028] The present invention has the following beneficial effects: the present invention provides a carbon nanocomposite conductive material, using carbon material as a conductive filler, and magnetic iron / PEDOT:PSS nanoparticles to replace part of the conductive filler, so that the cable shielding layer has the advantages of strong anti-interference ability, light weight, high strength and good flexibility. Modified magnetic iron nanoparticles are used as initiators, and aqueous reversible inactivation free radical polymerization is adopted to directly polymerize sodium 4-vinylbenzene sulfonate. Compared with styrene polymerization and grafting sulfonic acid groups, the obtained PSS has a grafting rate of 100%; the magnetic iron / PEDOT:PSS nanoparticles are grafted with conductive polymers on the surface of magnetic iron nanoparticles, thereby improving the dispersibility, stability and conductivity of magnetic iron nanoparticles. The magnetic core has excellent magnetic properties, and the outer layer is a conductive polymer, which can make the magnetic loss and dielectric loss reach an electromagnetic synergistic state, so that it can effectively shield electromagnetic interference at low frequency, medium frequency and high frequency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The synthesis route and structural schematic diagram of magnetic iron / PEDOT:PSS nanoparticles of the present invention;

[0030] Figure 2 This is the infrared spectrum of the synthesis of magnetic iron / PEDOT:PSS nanoparticles of the present invention; DETAILED DESCRIPTION

[0031] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] In the examples, the experimental methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used are all commercially available unless otherwise specified.

[0033] The raw materials and equipment used in the embodiments and comparative examples are described as follows:

[0034] In the examples, the experimental methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used are all commercially available unless otherwise specified.

[0035] The raw materials and equipment used in the embodiments and comparative examples are described as follows:

[0036] Rubber: Methyl vinyl silicone rubber (MVQ110-3), vinyl content of 0.19-0.24%;

[0037] Reinforcing agent: fumed silica, grade HP-200, purchased from Jiangxi Hongbai New Materials Co., Ltd.;

[0038] Carbon nanomaterials: carbon nanotubes, from carbon environment;

[0039] Silane coupling agent: vinyl triethoxysilane, purchased from Shanghai MacLean Biochemical Technology Co., Ltd.;

[0040] Antioxidant: Antioxidant 1010, purchased from Dongguan Guangsiyuan Polyurethane Materials Co., Ltd.;

[0041] Curing agent: 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, Shanghai MacLean Biochemical Technology Co., Ltd.;

[0042] Accelerator: triallyl isocyanurate, purchased from Shanghai MacLean Biochemical Technology Co., Ltd.;

[0043] Ferric nitrate: purchased from Shanghai MacLean Biochemical Technology Co., Ltd.;

[0044] Nickel nitrate: purchased from Sinopharm Reagent;

[0045] Sodium 4-vinylbenzenesulfonate: Guangzhou Yuanda New Materials;

[0046] 4-Chloromethylbenzoyl chloride: purchased from Shanghai MacLean Biochemical Technology Co., Ltd.;

[0047] Cuprous chloride: purity ≥99.95%, Shanghai Boer Chemical Reagent Co., Ltd.;

[0048] 2,2'-Bipyridine: Guangzhou Yuanda New Materials;

[0049] 3,4-Ethylenedioxythiophene: purchased from Shanghai MacLean Biochemical Technology Co., Ltd.;

[0050] Sodium polystyrene sulfonate: molecular weight: 50000-100000, purchased from Guangdong Wengjiang Chemical Reagent;

[0051] Benzoyl peroxide: purchased from Sinopharm Reagent.

[0052] Magnetic iron nanoparticles (NiFe2O4), homemade

[0053] At room temperature, 0.2 mol of ferric nitrate and 0.1 mol of nickel nitrate were added to 1000 ml of deionized water, and then 5 mol / L sodium hydroxide solution was slowly added to adjust the pH to 10. After mechanical stirring for 0.5 h, the solution was transferred to a steel autoclave lined with Teflon, sealed and heated at 110°C for 12 h, and then naturally cooled to room temperature. The resulting solution was centrifuged, and the obtained particles were dried in an oven at 60°C for 12 h, then placed in a muffle furnace, heated to 400°C at a heating rate of 3°C / min, maintained at 400°C for 2 h, and then naturally cooled to room temperature to obtain magnetic iron nanoparticles (NiFe2O4).

[0054] Magnetic Fe / PEDOT:PSS nanoparticles 1

[0055] S1. 10 g of magnetic iron nanoparticles were dispersed in an anhydrous solvent by ultrasonication. Under an inert atmosphere, 22 ml of triethylamine was added, and 8 g of 4-chloromethylbenzoyl chloride was dissolved in anhydrous dimethyl sulfoxide. The mixture was slowly added dropwise to the mixture, stirred at room temperature for 48 h, centrifuged, and the solid product was collected and vacuum dried to obtain modified magnetic iron nanoparticles.

[0056] S2. 18 mmol (3.7 g) of sodium 4-vinylbenzenesulfonate, 0.05 mmol of sodium chloride, 25 ml of deionized water and 11 ml of methanol solution were added to the reactor under stirring, and 1.6 g of modified magnetic iron nanoparticles obtained in step S1 were added together with 1 mol / L sodium hydroxide solution, and the pH was adjusted to 6-7. After freeze-thaw degassing, 0.05 mmol of cuprous chloride and 0.1 mmol of ligand 2,2'-bipyridine were added, and the reaction was carried out at room temperature for 3 h. After the reaction was completed, ice was added. Oxygen was introduced into the reaction system under bath conditions to terminate the polymerization reaction, the pH was adjusted to 4.5-5.5, centrifuged, the solid product was collected and dispersed in water, and then dispersed into two equal parts, 3.0 g of benzoyl peroxide was added to one part, and 1.48 g of 3,4-ethylenedioxythiophene was added to the other part. The two solutions were mixed and stirred at room temperature for 48 hours. The obtained solution was washed 3 times with chloroform, the pH of the obtained aqueous solution was adjusted to 6-8, centrifuged, and the solid product was collected to obtain magnetic iron / PEDOT:PSS nanoparticles 1.

[0057] Magnetic Fe / PEDOT:PSS nanoparticles 2

[0058] S1. 10 g of magnetic iron nanoparticles were dispersed in an anhydrous solvent by ultrasonication. Under an inert atmosphere, 22 ml of triethylamine was added, and 8 g of 4-chloromethylbenzoyl chloride was dissolved in anhydrous dimethyl sulfoxide. The mixture was slowly added dropwise to the mixture, stirred at room temperature for 48 h, centrifuged, and the solid product was collected and vacuum dried to obtain modified magnetic iron nanoparticles.

[0059] S2. 23 mmol (4.7 g) of sodium 4-vinylbenzenesulfonate, 0.1 mmol of sodium chloride, 32 ml of deionized water and 14 ml of methanol solution were added to the reactor under stirring, and 2.0 g of the modified magnetic iron nanoparticles obtained in step S1 were added together with 1 mol / L sodium hydroxide solution, the pH was adjusted to 6-7, and after freeze-thaw degassing, 0.1 mmol of cuprous chloride and 0.2 mmol of ligand 2,2'-bipyridine were added, and the reaction was carried out at room temperature for 3 hours. After the reaction was completed, oxygen was introduced into the reaction system under ice bath conditions to terminate the polymerization reaction, and the pH was adjusted to 4.5-5.5. The reaction was centrifuged, and the solid product was collected and dispersed in water. The solution was dispersed into two equal parts, 3.8 g of benzoyl peroxide was added to one part, and 1.88 g of 3,4-ethylenedioxythiophene was added to the other part. The two solutions were mixed and stirred at room temperature for 48 hours. The obtained solution was washed with chloroform three times, and the obtained aqueous solution was adjusted to pH 6-8. The solution was centrifuged and the solid product was collected to obtain magnetic iron / PEDOT:PSS nanoparticles 2.

[0060] Magnetic iron / PEDOT:PSS nanoparticles 3

[0061] Compared with the preparation method of magnetic iron / PEDOT:PSS nanoparticles 2, the difference is that in step S2, 2.0 g of modified magnetic iron nanoparticles are replaced by 0.47 g.

[0062] Magnetic Fe / PEDOT:PSS Nanoparticles 4

[0063] Compared with the preparation method of magnetic iron / PEDOT:PSS nanoparticles 2, the difference is that in step S2, 2.0 g of modified magnetic iron nanoparticles are replaced by 0.94 g.

[0064] Magnetic Fe / PEDOT:PSS Nanoparticles 5

[0065] Compared with the preparation method of magnetic iron / PEDOT:PSS nanoparticles 2, the difference is that in step S2, 2.0 g of modified magnetic iron nanoparticles are replaced by 3.1 g.

[0066] PEDOT:PSS

[0067] 4.7 g of sodium polystyrene sulfonate was dispersed in water and divided into two equal parts. 3.8 g of benzoyl peroxide was added to one part and 1.88 g of 3,4-ethylenedioxythiophene was added to the other part. The two solutions were mixed and stirred at room temperature for 48 h. The obtained solution was washed with chloroform three times. The pH of the obtained aqueous solution was adjusted to 6-8, centrifuged, and the solid product was collected to obtain PEDOT:PSS.

[0068] The cable shield is prepared by the following steps:

[0069] (1) After the carbon nanocomposite conductive material is stirred and dispersed, a reinforcing agent and a coupling agent are poured into a vacuum kneader, and then the silicone rubber raw rubber is slowly added. During the mixing process, the carbon nanocomposite conductive material is added in batches, and the kneader vacuum valve and exhaust valve are closed before mixing. After the filler and the raw rubber are evenly mixed, the kneader is heated to 150° C. and mixed for 2 h, and then vacuum kneaded at 115-125° C. for 1 h, and the silicone rubber masterbatch is obtained after cooling to room temperature;

[0070] (2) Antioxidant, vulcanizer and accelerator are added to the silicone rubber masterbatch by a double-roll mill, and the mixture is uniformly mixed to form a sheet. After vulcanization at a temperature of 180°C, 12 min and a pressure of 2.2 MPa, the thickness of the electromagnetic shielding rubber layer is 1 mm. After vulcanization, a cable shielding layer is obtained.

[0071] Table 1 Electromagnetic shielding rubber layer formulations of Examples 1 to 7 and Comparative Examples 1 to 3 (g)

[0072]

[0073] The following is the test method of the performance parameters involved in the present invention:

[0074] Shore A hardness: In accordance with GB / T 531.1-2008, it characterizes the hardness of vulcanized rubber.

[0075] Tensile properties: According to GB / T 528-2009, the tensile strength and elongation at break of the vulcanized rubber specimens were tested;

[0076] Electromagnetic shielding effectiveness test: GJB 8820-2015, the vulcanized rubber is made into a 15cm×15cm square sample with a thickness of 1mm, and the electromagnetic shielding effectiveness in the frequency band of 10kHz~80MHz is measured using the shielding room method.

[0077] Table 2 Electromagnetic shielding rubber layer performance test

[0078]

[0079] It can be seen from the data in Table 2 that the hard tensile properties of the prepared electromagnetic shielding rubber layer are all above 4.0Mpa, the average electromagnetic shielding effectiveness at 10kHz to 300kHz is greater than 50dB, and the average electromagnetic shielding effectiveness at 300kHz to 80MHz is greater than 60dB, which can meet the shielding effect of ordinary medical cables against power line interference and radio frequency interference.

[0080] It can be seen from the data of Examples 4 to 7 in Table 2 that the magnetic iron content mainly affects the electromagnetic shielding effectiveness in the frequency band of 10kHz to 300kHz, and the higher the external PEDOT:PSS content, the higher the elongation at break of the electromagnetic shielding rubber layer; it can be seen from the data of Comparative Example 1 that the physical properties and shielding properties of the electromagnetic shielding rubber layer obtained by ordinary physical blending of magnetic iron and PEDOT:PSS are poor.

[0081] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A carbon nanocomposite conductive material, comprising, by weight, 20 to 35 parts of magnetic iron / PEDOT:PSS nanoparticles and 40 to 65 parts of carbon nanomaterials; characterized in that: The magnetic iron / PEDOT:PSS nanoparticles are obtained by modifying the surface of magnetic iron nanoparticles with 3,4-ethylenedioxythiophene:poly(styrene sulfonic acid); the carbon nanomaterial is one or more of carbon black, graphene oxide, reduced graphene oxide and carbon nanotubes.

2. A carbon nanocomposite conductive material as claimed in claim 1, characterized in that: The preparation method of the magnetic iron / PEDOT:PSS nanoparticles is as follows: S1. The hydroxyl groups on the surface of the magnetic iron nanoparticles react with the halogenated acyl halide through an acylation reaction to obtain modified magnetic iron nanoparticles; S2. The halogen atoms of the modified magnetic iron nanoparticles are used to initiate the polymerization of sodium 4-vinylbenzenesulfonate to obtain magnetic iron nanoparticles with surface grafted poly(styrenesulfonic acid), and then 3,4-ethylenedioxythiophene is polymerized by benzoyl oxide to obtain magnetic iron / PEDOT:PSS nanoparticles.

3. The carbon nanocomposite conductive material according to claim 1, characterized in that: The preparation method of the magnetic iron / PEDOT:PSS nanoparticles is as follows: S1. The magnetic iron nanoparticles are dispersed in an anhydrous solvent by ultrasonication, and an acid binding agent is added under an inert atmosphere, and then the halogenated acyl halide is dissolved in an anhydrous solvent, and the mixture is slowly added dropwise to the mixture, and stirred at room temperature for 24 to 48 hours, centrifuged, and the solid product is collected and vacuum dried to obtain modified magnetic iron nanoparticles; S2. Sodium 4-vinylbenzenesulfonate, chloride or bromide, and polar protic solvent are added to a reactor under stirring, and the modified magnetic iron nanoparticles obtained in step S1 are added together with a sodium hydroxide solution, and the pH is adjusted to 6-10. After freeze-thaw degassing, cuprous ions and ligand 2,2'-bipyridine are added, and the reaction is carried out at room temperature for 3-6 hours. After the reaction is completed, oxygen is introduced into the reaction system under ice bath conditions to terminate the polymerization reaction, and the pH is adjusted to 4-6. The solid product is centrifuged, collected and dispersed in water, and divided into two equal parts, benzoyl peroxide is added to one part, and 3,4-ethylenedioxythiophene is added to the other part. The two solutions are mixed and stirred continuously at room temperature for 16-48 hours. The resulting solution is post-treated to obtain magnetic iron / PEDOT:PSS nanoparticles.

4. The carbon nanocomposite conductive material according to claim 1, characterized in that: The magnetic iron nanoparticles are magnetic Fe3O4 nanoparticles, magnetic NiFe2O4 nanoparticles, magnetic CoFe2O4 nanoparticles, magnetic MnFe2O4 nanoparticles and magnetic BaFe 12 O 19 One or more nanoparticles.

5. The carbon nanocomposite conductive material according to claim 3, characterized in that: In step S1, the halogenated acyl halide is one or more of 4-chloromethylbenzoyl chloride, 3-(chloromethyl)benzoyl chloride, 2-bromoisobutyryl bromide, 2-chloroisobutyryl chloride, chloroacetyl chloride and bromoacetyl bromide; the acid binding agent is at least one of triethylamine and pyridine; the solvent is one or more of dimethyl sulfoxide, dichloromethane and dimethylformamide; the mass ratio of the magnetic iron nanoparticles: the acid binding agent: the halogenated acyl halide is 1: (1.5-2): (0.5-1).

6. The carbon nanocomposite conductive material according to claim 3, characterized in that: In step S2, the chloride salt is at least one of potassium chloride and sodium chloride, and the bromide salt is at least one of sodium bromide and potassium bromide; the cuprous ion is at least one of cuprous bromide or cuprous chloride; the concentration of the sodium hydroxide solution is 1-2 mol / L; the mass ratio of the modified magnetic iron nanoparticles to sodium 4-vinylbenzenesulfonate is 1:(1.5-10); the molar ratio of the sodium 4-vinylbenzenesulfonate, cuprous ions, ligand 2,2'-bipyridine, chloride salt or bromide salt is (180-230):(0.5-1):(1-2):(0.05-10); the mass ratio of sodium 4-vinylbenzenesulfonate, 3,4-ethylenedioxythiophene and benzoyl peroxide is (2-5):1:(0.5-2); the polar protic solvent is at least one of water and methanol, water and ethanol, and the volume fraction of the alcohol in the solution is 0-50%.

7. The carbon nanocomposite conductive material according to claim 3, characterized in that: The post-treatment step in step S2 is to wash the obtained solution with chloroform at least twice, adjust the pH of the obtained aqueous solution to 6-8, centrifuge, and collect the solid product to obtain magnetic iron / PEDOT:PSS nanoparticles.

8. Use of the carbon nanocomposite conductive material as claimed in any one of claims 1 to 7 in a cable shielding layer.

9. The use of a carbon nanocomposite conductive material in a cable shielding layer as claimed in claim 8, characterized in that: The cable shielding layer comprises, by weight, 90 to 100 parts of rubber, 10 to 20 parts of reinforcing agent, 60 to 95 parts of carbon nanocomposite conductive material, 4 to 5 parts of silane coupling agent, 1 to 1.3 parts of antioxidant, 2 to 4 parts of vulcanizing agent, and 1 to 2 parts of accelerator; the cable shielding layer is prepared by the following steps: (1) After the carbon nanocomposite conductive material is stirred and dispersed, a reinforcing agent and a coupling agent are poured into a vacuum kneader, and then the silicone rubber raw rubber is slowly added. During the mixing process, the carbon nanocomposite conductive material is added in batches, and the kneader vacuum valve and exhaust valve are closed before mixing. After the filler and the raw rubber are evenly mixed, the kneader is heated to 145-155° C. and mixed for 2-3 hours, and then vacuum kneaded at 115-125° C. for 1-2 hours, and then cooled to room temperature to obtain a silicone rubber masterbatch; (2) Add antioxidant, vulcanizing agent and accelerator to silicone rubber masterbatch by double-roll mill, mix well and produce sheets, extrude them on cable insulation layer by extruder, and obtain cable shielding layer after vulcanization.

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