Anti-aging conductive foam and preparation method thereof

Abstract

The invention discloses anti-aging conductive foam and a preparation method thereof, and belongs to the technical field of conductive materials. The anti-aging conductive foam is prepared from the following components in parts by weight: 30 to 40 parts of triazinyl propylene glycol, 30 to 40 parts of polyethylene glycol, 5 to 10 parts of a flame retardant, 2 to 6 parts of a chain extender, 0.5 to 2 parts of a surfactant, 1 to 5 parts of a foaming agent, 5 to 15 parts of modified carbon nanotubes, 0.1 to 1 part of a catalyst and 100 to 110 parts of diisocyanate, the conductive foam is polyurethane foam, the preparation method is simple, the conductive foam is prepared by wrapping the foam body with the conductive cloth for composite molding, and the formula of the foam is improved, so that the conductive foam has different conductivity, aging resistance and mechanical properties.

Description

Technical Field

[0001] The present invention relates to the technical field of conductive materials, and in particular to an aging-resistant conductive foam and a preparation method thereof. Background Art

[0002] With the rapid development of electronic information technology, the integration density and operating frequency of electronic devices are constantly increasing, and electromagnetic interference is becoming increasingly serious, which has led to an increasing demand for electromagnetic shielding materials. Conductive foam, as an important electromagnetic shielding material, has advantages such as good conductivity, strong compression resilience, and easy installation, and is widely used in electronic products.

[0003] Chinese patent document CN222223653U discloses a flame-retardant conductive foam. The foam comprises a cylindrical, three-layer hot-pressed structure, formed from the inside out by sequentially hot-pressing a foam base layer, a conductive layer, and a flame-retardant layer. The base layer is made of polyurethane foam, polyether foam, or polyethylene foam, with polyurethane foam being preferred. The conductive layer is filled with graphene powder, which accounts for 10-30% of the total mass of the foam. The graphene powder exhibits excellent conductivity and flexibility, meeting the requirements of conductive foam applications. The flame-retardant layer is filled with one of aluminum hydroxide, magnesium hydroxide, and zinc borate. This utility model not only exhibits excellent conductivity but also high flame retardancy, effectively preventing fires. The graphene used in this patent exhibits poor bonding with the foam, resulting in low load transfer efficiency and prone to migration over long-term use, leading to performance degradation.

[0004] Most existing conductive foams are based on polyurethane or silicone rubber. During long-term use, especially under harsh environmental conditions such as high temperature, high humidity, and ultraviolet radiation, molecular chains break and they are prone to aging, resulting in a decline in mechanical properties. Therefore, it is necessary to propose a preparation method for aging-resistant conductive foam. Summary of the Invention

[0005] The main purpose of the present invention is to provide an aging-resistant conductive foam and a preparation method thereof. By adding triazine propanediol and modified carbon nanotubes into the formula, the conductive foam has excellent conductivity, aging resistance and mechanical properties.

[0006] To achieve the above objectives, the present invention proposes an aging-resistant conductive foam, comprising the following components in parts by weight: 30-40 parts of triazine propylene glycol, 30-40 parts of polyethylene glycol, 5-10 parts of a flame retardant, 2-6 parts of a chain extender, 0.5-2 parts of a surfactant, 1-5 parts of a foaming agent, 5-15 parts of modified carbon nanotubes, 0.1-1 parts of a catalyst and 100-110 parts of a diisocyanate.

[0007] Preferably, the preparation method of the triazine-propylene glycol is as follows: 2,4,6-tris(4-formylphenyl)-1,3,5-triazine, 2-amino-2-methyl-1,3-propanediol and N,N-dimethylformamide are mixed evenly, heated for reaction, the solvent is evaporated under reduced pressure and then subjected to column chromatography to obtain triazine-based propanediol.

[0008] The present invention grafts triazine groups onto propylene glycol, thereby facilitating the formation of an ultraviolet shielding layer on the surface of the polyurethane generated by the subsequent polymerization reaction, and effectively suppressing the discoloration and yellowing of the polyurethane foam under the action of ultraviolet rays.

[0009] Preferably, the mass ratio of the 2,4,6-tris(4-formaldehydephenyl)-1,3,5-triazine to 2-amino-2-methyl-1,3-propanediol is 1:1.5-2; the heating reaction temperature is 50-70° C., and the reaction time is 2-4 hours.

[0010] Preferably, the flame retardant is at least one of melamine cyanurate, polyphosphate cyanurate, melamine, aluminum hydroxide, and magnesium hydroxide.

[0011] Preferably, the chain extender is at least one of 1,4-butanediol, ethylene glycol, propylene glycol, methylpropylene glycol, diethylene glycol, 1,4-cyclohexanol, neopentyl glycol, 1,6-hexanediol, 1,5-pentanediol, 1,3-butanediol, trimethylolpropane, and glycerol.

[0012] Preferably, the foaming agent is water.

[0013] Preferably, the preparation method of the modified carbon nanotubes is as follows: The carbon nanotubes are dispersed in a mixed acid solution of concentrated sulfuric acid and concentrated nitric acid, heated and stirred after ultrasonic treatment, cooled to room temperature, filtered, the solids are collected, washed with water until neutral, dried, dispersed in an ethanol aqueous solution, KH550 is added, and heated to react to obtain amino carbon nanotubes; caffeic acid is dissolved in dimethyl sulfoxide, and the amino carbon nanotubes, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, and N-hydroxysuccinimide are added, stirred for reaction, filtered, the solids are collected, washed and dried, and then added to N,N-dimethylformamide, DOPO and tetrabutylammonium bromide are added, the temperature is increased to react under nitrogen protection, filtered, the solids are collected, washed and dried to obtain modified carbon nanotubes.

[0014] Further preferably, the mass ratio of the carbon nanotubes, KH550, caffeic acid, and DOPO is 10-20:2-3:3-5:1.3-1.5; the heating reaction temperature is 40-60°C, and the reaction time is 2-4 hours; the stirring reaction temperature is 60-80°C, and the reaction time is 6-8 hours; the temperature of the warming reaction is 50-80°C, and the reaction time is 3-5 hours.

[0015] Carbon nanotubes are a type of nanomaterial with high-temperature resistance, electrical conductivity, thermal conductivity and flame retardancy. The present invention effectively prevents carbon nanotube agglomeration by modifying the carbon nanotubes, improves the interfacial bonding between the carbon nanotubes and the polyurethane matrix, forms a stable conductive network, and can react with diisocyanates to construct a strong interfacial bonding network at the molecular level and achieve efficient load transfer, fully exerting the reinforcing and conductive effects of the carbon nanotubes, and making them less likely to migrate or fall off during long-term use.

[0016] Preferably, the catalyst is one of stannous octoate, dibutyltin dilaurate and dibutyltin diacetate.

[0017] Preferably, the diisocyanate is at least one of toluene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, triphenylmethane triisocyanate, xylylene diisocyanate, and p-phenylene diisocyanate.

[0018] The present invention also discloses a method for preparing the above-mentioned aging-resistant conductive foam, which comprises the following steps: The raw materials are weighed according to the formula, and triazine propylene glycol, polyethylene glycol, flame retardant, chain extender, silicone oil, foaming agent, modified carbon nanotubes and catalyst are evenly mixed to prepare a mixture; the mixture and diisocyanate are evenly mixed and poured into a mold, and cured at 50-60°C for 0.5-4h. The mold is demolded to obtain aging-resistant polyurethane foam, and finally the conductive cloth and the aging-resistant polyurethane foam are composited to obtain aging-resistant conductive foam.

[0019] Preferably, the conductive cloth is one of carbon-plated conductive cloth, nickel-plated conductive cloth, and aluminum foil fiber composite cloth.

[0020] Compared with the prior art, the present invention has the following beneficial effects: 1) The conductive foam of the present invention is a polyurethane foam with a simple preparation method. It is made by wrapping a conductive cloth around the foam body and then forming it into a composite shape. By improving the foam formula, the conductive foam has excellent conductivity, aging resistance and mechanical properties. 2) The triazine-based propylene glycol of the present invention is prepared by a Schiff base reaction between the aldehyde group on 2,4,6-tris(4-formylphenyl)-1,3,5-triazine and the amino group on 2-amino-2-methyl-1,3-propanediol. Triazine groups are introduced into the propylene glycol, and then the triazine groups are grafted onto the side ends of the polyurethane molecular segments through a polymerization reaction. This does not affect the original excellent mechanical properties of the polyurethane, such as compression resilience and flexibility. The triazine groups are enriched on the surface to form a UV shielding layer, which effectively suppresses discoloration and yellowing of the polyurethane foam under the action of ultraviolet rays. 3) Preparation of modified carbon nanotubes of the present invention First, the carbon nanotubes are activated by concentrated sulfuric acid and concentrated nitric acid, and then treated with KH550 to introduce active amino groups on their surfaces. Then, under the action of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide, the carboxyl groups on caffeic acid react to graft caffeic acid onto the carbon nanotubes, and carbon-carbon double bonds are introduced. The semi-rigid aromatic ring structure of caffeic acid is introduced into the interface region, and the interface interaction is enhanced by π-π stacking and van der Waals forces. More importantly, the phenolic hydroxyl groups in the caffeic acid molecules can react with the isocyanate groups during the polyurethane curing process to form amino groups. The DOPO-containing flame retardant groups are efficiently grafted onto the surface of the carbon nanotubes. The thermal conductivity of the carbon nanotubes themselves is combined with the flame retardancy of DOPO to form a synergistic thermal protection effect. The carbon layer formed by DOPO catalysis at high temperature is combined with the carbon nanotube skeleton to form a denser flame retardant barrier, which significantly improves the flame retardancy and heat resistance of the composite material. DETAILED DESCRIPTION

[0021] To avoid redundancy, the items used in the following examples are all commercially available products unless otherwise specified, and the methods used are all conventional methods unless otherwise specified.

[0022] The sources of some raw materials used in the present invention are as follows: Carbon nanotubes, with a particle size of 1-2 mm, were purchased from Zhongke Leiming (Beijing) Technology Co., Ltd.

[0023] Example 1 A method for preparing aging-resistant conductive foam comprises the following steps: 35 g of triazine propylene glycol, 35 g of polyethylene glycol, 8 g of melamine cyanurate, 4.2 g of ethylene glycol, 1 g of silicone oil, 2.6 g of water, 10 g of modified carbon nanotubes and 0.5 g of stannous octoate were mixed evenly to prepare a mixture; the mixture was mixed evenly with 105 g of toluene diisocyanate and poured into a mold, cured at 60° C. for 1 h, and demolded to obtain aging-resistant polyurethane foam. Finally, nickel-plated conductive cloth and aging-resistant polyurethane foam were composited to obtain aging-resistant conductive foam.

[0024] The preparation method of the triazine-based propylene glycol comprises the following steps: uniformly mixing 5 g of 2,4,6-tris(4-formaldehydephenyl)-1,3,5-triazine, 9 g of 2-amino-2-methyl-1,3-propanediol, and 200 mL of N,N-dimethylformamide, heating the mixture at 60° C. for reaction for 3 h, and then removing the solvent under reduced pressure after the reaction is completed. The mixture is then subjected to column chromatography to obtain the triazine-based propylene glycol.

[0025] The preparation method of the modified carbon nanotubes is as follows: 15 g of carbon nanotubes were dispersed in a mixed acid solution of 100 ml of concentrated sulfuric acid and 50 ml of concentrated nitric acid, ultrasonically treated for 30 min, stirred at 80 ° C for 4 h, cooled to room temperature, filtered, washed with water until neutral, dried, and dispersed in 150 mL of 50 wt% ethanol aqueous solution; 2.5 g of KH550 was added, heated at 50 ° C for 3 h, filtered after the reaction was completed, the solid was collected, washed and dried to obtain amino carbon nanotubes; 4 g of caffeic acid was dissolved in 20 mL of dimethyl sulfoxide, and amino carbon nanotubes, 2 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide, and 2 g of N-hydroxysuccinimide were added. The mixture was stirred at 70 ° C for 7 h, filtered, the solid was collected, washed and dried, and then added to 200 mL of N,N-dimethylformamide, 1.5 g of DOPO and 0.5 g of tetrabutylammonium bromide were added, and the mixture was heated to 70 ° C for 4 h under nitrogen protection. The reaction was filtered, the solid was collected, washed and dried to obtain modified carbon nanotubes.

[0026] Example 2 A method for preparing aging-resistant conductive foam comprises the following steps: 30 g of triazine propylene glycol, 30 g of polyethylene glycol, 5 g of melamine cyanurate, 2 g of ethylene glycol, 0.5 g of silicone oil, 1 g of water, 5 g of modified carbon nanotubes and 0.5 g of stannous octoate were mixed evenly to prepare a mixture; the mixture was evenly mixed with 100 g of toluene diisocyanate and poured into a mold, cured at 50°C for 0.5 h, and demolded to obtain aging-resistant polyurethane foam. Finally, nickel-plated conductive cloth and aging-resistant polyurethane foam were composited to obtain aging-resistant conductive foam.

[0027] The preparation method of the triazine-based propylene glycol comprises the following steps: uniformly mixing 5 g of 2,4,6-tris(4-formaldehydephenyl)-1,3,5-triazine, 7.5 g of 2-amino-2-methyl-1,3-propanediol, and 200 mL of N,N-dimethylformamide, heating the mixture at 50° C. for 4 h, and removing the solvent under reduced pressure after the reaction is completed. The mixture is then purified by column chromatography to obtain the triazine-based propylene glycol.

[0028] The preparation method of the modified carbon nanotubes is as follows: 10g of carbon nanotubes were dispersed in a mixed acid solution of 100ml of concentrated sulfuric acid and 50ml of concentrated nitric acid, ultrasonically treated for 30min, stirred at 80℃ for 4h, cooled to room temperature, filtered, washed with water until neutral, dried and dispersed in 150mL of 50wt% ethanol aqueous solution; 2.5g of KH550 was added, heated at 50℃ for 3h, filtered after the reaction was completed, the solid was collected, washed and dried to obtain amino carbon nanotubes; 4g of caffeic acid was dissolved in 20mL of dimethyl sulfoxide, and amino carbon nanotubes, 1.6g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 1.6g of N-hydroxysuccinimide were added, stirred at 70℃ for 6h, filtered, the solid was collected, washed and dried, and added to 200mL of N,N-dimethylformamide, and 1.3g DOPO and 0.3 g of tetrabutylammonium bromide were heated to 50° C. under nitrogen protection for reaction for 5 h, filtered, and the solid was collected, washed, and dried to obtain modified carbon nanotubes.

[0029] Example 3 A method for preparing aging-resistant conductive foam comprises the following steps: 40 g of triazine propylene glycol, 40 g of polyethylene glycol, 10 g of melamine cyanurate, 6 g of ethylene glycol, 2 g of silicone oil, 5 g of water, 15 g of modified carbon nanotubes and 1 g of stannous octoate were mixed evenly to prepare a mixture; the mixture was mixed evenly with 110 g of toluene diisocyanate and poured into a mold, cured at 50°C for 0.5 h, and demolded to obtain aging-resistant polyurethane foam. Finally, nickel-plated conductive cloth and aging-resistant polyurethane foam were composited to obtain aging-resistant conductive foam.

[0030] The preparation method of the triazine-based propylene glycol comprises the following steps: uniformly mixing 5 g of 2,4,6-tris(4-formaldehydephenyl)-1,3,5-triazine, 10 g of 2-amino-2-methyl-1,3-propanediol, and 200 mL of N,N-dimethylformamide, heating the mixture at 70° C. for 2 h, and removing the solvent under reduced pressure after the reaction is completed. The mixture is then subjected to column chromatography to obtain the triazine-based propylene glycol.

[0031] The preparation method of the modified carbon nanotubes is as follows: 20g of carbon nanotubes were dispersed in a mixed acid solution of 100ml of concentrated sulfuric acid and 50ml of concentrated nitric acid, ultrasonically treated for 30min, stirred at 80℃ for 4h, cooled to room temperature, filtered, washed with water until neutral, dried and dispersed in 150mL of 50wt% ethanol aqueous solution; 3g of KH550 was added, heated at 60℃ for 2h, filtered after the reaction was completed, the solid was collected, washed and dried to obtain amino carbon nanotubes; 5g of caffeic acid was dissolved in 20mL of dimethyl sulfoxide, and amino carbon nanotubes, 2.5g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 2.5g of N-hydroxysuccinimide were added, stirred at 80℃ for 6h, filtered, the solid was collected, washed and dried, and added to 200mL of N,N-dimethylformamide, and 1.5g of DOPO and 0.5 g of tetrabutylammonium bromide were heated to 80° C. under nitrogen protection for reaction for 3 h, filtered, and the solid was collected, washed, and dried to obtain modified carbon nanotubes.

[0032] Comparative Example 1 35 g of 2-methyl-1,3-propanediol, 35 g of polyethylene glycol, 8 g of melamine cyanurate, 4.2 g of ethylene glycol, 1 g of silicone oil, 2.6 g of water, 10 g of modified carbon nanotubes and 0.5 g of stannous octoate were mixed evenly to prepare a mixture; the mixture was evenly mixed with 105 g of toluene diisocyanate and poured into a mold, and cured at 60° C. for 1 h. The mold was demolded to obtain aging-resistant polyurethane foam, and finally the nickel-plated conductive cloth and the aging-resistant polyurethane foam were composited to obtain aging-resistant conductive foam.

[0033] The preparation method of the modified carbon nanotubes is as follows: 15 g of carbon nanotubes were dispersed in a mixed acid solution of 100 ml of concentrated sulfuric acid and 50 ml of concentrated nitric acid, ultrasonically treated for 30 min, stirred at 80 ° C for 4 h, cooled to room temperature, filtered, washed with water until neutral, dried, and dispersed in 150 mL of 50 wt% ethanol aqueous solution; 2.5 g of KH550 was added, heated at 50 ° C for 3 h, filtered after the reaction was completed, the solid was collected, washed and dried to obtain amino carbon nanotubes; 4 g of caffeic acid was dissolved in 20 mL of dimethyl sulfoxide, and amino carbon nanotubes, 2 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide, and 2 g of N-hydroxysuccinimide were added. The mixture was stirred at 70 ° C for 7 h, filtered, the solid was collected, washed and dried, and then added to 200 mL of N,N-dimethylformamide, 1.5 g of DOPO and 0.5 g of tetrabutylammonium bromide were added, and the mixture was heated to 70 ° C for 4 h under nitrogen protection. The reaction was filtered, the solid was collected, washed and dried to obtain modified carbon nanotubes.

[0034] Comparative Example 2 A method for preparing aging-resistant conductive foam comprises the following steps: 35 g of triazine propylene glycol, 35 g of polyethylene glycol, 8 g of melamine cyanurate, 4.2 g of ethylene glycol, 1 g of silicone oil, 2.6 g of water, 10 g of modified carbon nanotubes and 0.5 g of stannous octoate were mixed evenly to prepare a mixture; the mixture was mixed evenly with 105 g of toluene diisocyanate and poured into a mold, cured at 60° C. for 1 h, and demolded to obtain aging-resistant polyurethane foam. Finally, nickel-plated conductive cloth and aging-resistant polyurethane foam were composited to obtain aging-resistant conductive foam.

[0035] The preparation method of the triazine-based propylene glycol comprises the following steps: uniformly mixing 5 g of 2,4,6-tris(4-formaldehydephenyl)-1,3,5-triazine, 9 g of 2-amino-2-methyl-1,3-propanediol, and 200 mL of N,N-dimethylformamide, heating the mixture at 60° C. for reaction for 3 h, and then removing the solvent under reduced pressure after the reaction is completed. The mixture is then subjected to column chromatography to obtain the triazine-based propylene glycol.

[0036] The preparation method of the modified carbon nanotubes is as follows: 15g of carbon nanotubes were dispersed in a mixed acid solution of 100ml of concentrated sulfuric acid and 50ml of concentrated nitric acid, ultrasonically treated for 30min, stirred at 80℃ for 4h, cooled to room temperature, filtered, washed with water until neutral, dried and dispersed in 150mL of 50wt% ethanol aqueous solution; 2.5g of KH550 was added, heated at 50℃ for 3h, filtered after the reaction was completed, the solid was collected, washed and dried to obtain amino carbon nanotubes; 4g of caffeic acid was dissolved in 20mL of dimethyl sulfoxide, and amino carbon nanotubes, 2g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 2g of N-hydroxysuccinimide were added, stirred at 70℃ for 7h, filtered, the solid was collected, washed and dried to obtain modified carbon nanotubes.

[0037] Comparative Example 3 A method for preparing aging-resistant conductive foam comprises the following steps: 35 g of triazine propylene glycol, 35 g of polyethylene glycol, 8 g of melamine cyanurate, 4.2 g of ethylene glycol, 1 g of silicone oil, 2.6 g of water, 10 g of modified carbon nanotubes and 0.5 g of stannous octoate were mixed evenly to prepare a mixture; the mixture was mixed evenly with 105 g of toluene diisocyanate and poured into a mold, cured at 60° C. for 1 h, and demolded to obtain aging-resistant polyurethane foam. Finally, nickel-plated conductive cloth and aging-resistant polyurethane foam were composited to obtain aging-resistant conductive foam.

[0038] The preparation method of the triazine-based propylene glycol comprises the following steps: uniformly mixing 5 g of 2,4,6-tris(4-formaldehydephenyl)-1,3,5-triazine, 9 g of 2-amino-2-methyl-1,3-propanediol, and 200 mL of N,N-dimethylformamide, heating the mixture at 60° C. for reaction for 3 h, and evaporating the solvent under reduced pressure after the reaction is completed to obtain the triazine-based propylene glycol.

[0039] The modified carbon nanotubes are prepared by mixing 15 g of carbon nanotubes, 4 g of caffeic acid, and 1.5 g of DOPO and stirring them uniformly.

[0040] Performance Testing The test objects were the aging-resistant conductive foams prepared in Examples 1-3 and Comparative Examples 1-3, wherein the tensile strength was tested in accordance with GB / T6344-2008. The anti-aging performance test conditions were as follows: the samples were placed in a xenon aging test chamber, irradiated with ultraviolet rays of 290-340nm, with a rated power of 1.8kW, a temperature of (60±3)°C, a relative humidity of (50±5)%, and an ultraviolet aging time of 200h. The tensile strength of the samples before and after aging was compared, i.e., the anti-aging performance = tensile strength after aging / tensile strength before aging. The limiting oxygen index was tested in accordance with ASTM D2863-17. The test results are shown in Table 1: Table 1 Test results of aging-resistant conductive foam It can be seen from the experimental results in Table 1 that the aging-resistant conductive foam prepared in the present application has good mechanical, aging-resistant and flame-retardant properties.

[0041] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of the present invention.

Claims

1. An aging-resistant conductive foam, characterized in that: The invention comprises the following components in parts by weight: 30-40 parts of triazine propylene glycol, 30-40 parts of polyethylene glycol, 5-10 parts of flame retardant, 2-6 parts of chain extender, 0.5-2 parts of silicone oil, 1-5 parts of foaming agent, 5-15 parts of modified carbon nanotubes, 0.1-1 parts of catalyst and 100-110 parts of diisocyanate.

2. The aging-resistant conductive foam according to claim 1, characterized in that: The preparation method of the triazine-propylene glycol is as follows: 2,4,6-tris(4-formylphenyl)-1,3,5-triazine, 2-amino-2-methyl-1,3-propanediol and N,N-dimethylformamide are mixed evenly, heated for reaction, the solvent is evaporated under reduced pressure and then subjected to column chromatography to obtain triazine-based propanediol.

3. The aging-resistant conductive foam according to claim 2, characterized in that: The mass ratio of the 2,4,6-tris(4-formylphenyl)-1,3,5-triazine to 2-amino-2-methyl-1,3-propanediol is 1:1.5-2.

4. The aging-resistant conductive foam according to claim 1, characterized in that: The flame retardant is at least one of melamine cyanurate, polyphosphate cyanurate, melamine, aluminum hydroxide, and magnesium hydroxide.

5. The aging-resistant conductive foam according to claim 1, characterized in that: The foaming agent is water.

6. The aging-resistant conductive foam according to claim 1, characterized in that: The preparation method of the modified carbon nanotubes is as follows: The carbon nanotubes are dispersed in a mixed acid solution of concentrated sulfuric acid and concentrated nitric acid, heated and stirred after ultrasonic treatment, cooled to room temperature, filtered, the solids are collected, washed with water until neutral, dried, dispersed in an ethanol aqueous solution, KH550 is added, and heated to react to obtain amino carbon nanotubes; caffeic acid is dissolved in dimethyl sulfoxide, and the amino carbon nanotubes, 1-ethyl-(3-dimethylaminopropyl)carbodiimide, and N-hydroxysuccinimide are added, stirred for reaction, filtered, the solids are collected, washed and dried, and then added to N,N-dimethylformamide, DOPO and tetrabutylammonium bromide are added, the temperature is increased to react under nitrogen protection, filtered, the solids are collected, washed and dried to obtain modified carbon nanotubes.

7. The aging-resistant conductive foam according to claim 6, characterized in that: The mass ratio of the carbon nanotubes, KH550, caffeic acid and DOPO is 10-20:2-3:3-5:1.3-1.

5.

8. The aging-resistant conductive foam according to claim 1, characterized in that: The catalyst is one of stannous octoate, dibutyltin dilaurate and dibutyltin diacetate.

9. The aging-resistant conductive foam according to claim 1, characterized in that: The diisocyanate is at least one of toluene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, triphenylmethane triisocyanate, xylylene diisocyanate and p-phenylene diisocyanate.

10. A method for preparing the aging-resistant conductive foam according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: weighing raw materials according to a formula, uniformly mixing triazine propylene glycol, polyethylene glycol, flame retardant, chain extender, silicone oil, foaming agent, modified carbon nanotubes and catalyst to prepare a mixture; uniformly mixing the mixture with diisocyanate and pouring the mixture into a mold, curing the mixture at 50-60°C for 0.5-4h, demolding the mixture to obtain aging-resistant polyurethane foam, and finally compounding the conductive cloth with the aging-resistant polyurethane foam to obtain aging-resistant conductive foam.

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