阅读说明：本技术 一种高弹性高导热的三维碳纳米管复合材料的制备方法 (Preparation method of high-elasticity high-heat-conductivity three-dimensional carbon nanotube composite material ) 是由 封伟 张飞 冯奕钰 高龙 吕峰 于 2018-09-04 设计创作，主要内容包括：本发明公开一种高弹性高导热的三维碳纳米管复合材料的制备方法,利用硫酸铜附着在碳纳米管表面,然后通过高温处理使得硫酸铜分解为氧化铜,再通过高温下氢气还原成单质铜,由于铜也具有高导热性能,铜颗粒附着在碳纳米管的表面,在碳管的节点处形成焊接的节点,从而提高热量在碳管之间的传递,增强了材料的整体性和致密性,提高了碳纳米管海绵体的导热性能和力学性能,其导热系数>2W/mK,压缩50％后回弹率在95％以上。(The invention discloses a preparation method of a high-elasticity high-heat-conductivity three-dimensional carbon nanotube composite material, which is characterized in that copper sulfate is attached to the surface of a carbon nanotube, then the copper sulfate is decomposed into copper oxide through high-temperature treatment, and then the copper oxide is reduced into simple substance copper through hydrogen at high temperature, copper particles are attached to the surface of the carbon nanotube, and welded nodes are formed at the nodes of the carbon nanotube, so that the heat transfer between the carbon nanotubes is improved, the integrity and the compactness of the material are enhanced, the heat conductivity and the mechanical property of a carbon nanotube sponge body are improved, the heat conductivity coefficient is more than 2W/mK, and the resilience rate is more than 95% after the carbon nanotube sponge body is compressed by 50%.)

1. The preparation method of the three-dimensional carbon nanotube composite material with high elasticity and high heat conductivity is characterized by comprising the following steps of:

step 1, dipping a carbon nano tube sponge in a copper sulfate solution to obtain a copper sulfate coated carbon nano tube sponge;

and 2, placing the copper sulfate coated carbon nano tube sponge body obtained in the step 1 into a tube furnace, heating to 600-700 ℃ from the room temperature of 20-25 ℃ at the heating rate of 1-10 ℃ per minute in the atmosphere of inert protective gas, carrying out heat preservation reaction to decompose copper sulfate to generate copper oxide particles, then cooling to 400-500 ℃ at the cooling rate of 1-10 ℃ per minute, carrying out heat preservation treatment by taking hydrogen and inert protective gas as the atmosphere to reduce copper oxide, converting the copper oxide into copper particles, and finally cooling to the room temperature of 20-25 ℃ along with the furnace.

2. The method for preparing the three-dimensional carbon nanotube composite material with high elasticity and high thermal conductivity as claimed in claim 1, wherein in the step 1, copper sulfate is uniformly dispersed in an organic solvent to form a copper sulfate solution, and the concentration of the copper sulfate is 0.1-0.5 g/ml.

3. The method for preparing the three-dimensional carbon nanotube composite material with high elasticity and high thermal conductivity according to claim 2, wherein the organic solvent is N, N-dimethylformamide, N-dimethylacetamide or tetrahydrofuran.

4. The method of claim 1, wherein the step 1 is performed by dipping in a vacuum environment for 1-5 hours.

5. The method for preparing the three-dimensional carbon nanotube composite material with high elasticity and high thermal conductivity according to claim 1, wherein in the step 2, the inert shielding gas is nitrogen, helium or argon.

6. The method for preparing the three-dimensional carbon nanotube composite material with high elasticity and high thermal conductivity according to claim 1, wherein in the step 2, the temperature rising speed is 5-10 ℃ per minute, and the temperature lowering speed is 5-10 ℃ per minute.

7. The method for preparing the three-dimensional carbon nanotube composite material with high elasticity and high thermal conductivity according to claim 1, wherein the reaction is carried out at 600-700 ℃ for 30-90 min, preferably at 650-700 ℃ for 30-60 min.

8. The method for preparing the three-dimensional carbon nanotube composite material with high elasticity and high thermal conductivity according to claim 1, wherein in the step 2, the reaction is carried out at 400-500 ℃ for 30-90 min, preferably at 450-500 ℃ for 30-60 min.

9. The method for preparing a three-dimensional carbon nanotube composite material with high elasticity and high thermal conductivity as claimed in claim 1, wherein in step 2, the flow rate of hydrogen is 100 to 500sccm, the flow rate of inert shielding gas is 100 to 500sccm, preferably the flow rate of hydrogen is 100 to 300sccm, and the flow rate of inert shielding gas is 100 to 300 sccm.

10. The method for preparing the three-dimensional carbon nanotube composite material with high elasticity and high thermal conductivity as claimed in claim 1, wherein in step 1, the sample is dried in an oven after dipping to obtain a copper sulfate coated carbon nanotube sponge, and the drying is selected to be carried out at 80-100 ℃ for 20-24 hours.

Technical Field

The invention belongs to the technical field of composite materials, and particularly relates to a method for preparing a high-thermal-conductivity and compression-resilience three-dimensional carbon nanotube material, which relates to a method for preparing a high-thermal-conductivity and elastic carbon nanotube/copper composite material by using a metal node welding technology.

Background

With the continuous development of science and technology, the miniaturization and high power of electronic products are more and more popularized, and the heat management becomes an important factor for restricting the further development of the electronic products. Heat conduction and heat dissipation are a key problem in the mechanical and electronic industries, and along with the continuous strengthening and upgrading of the performance of electrical equipment, the integration level of electronic elements is higher, the heat generated in unit area is continuously increased, the heat cannot be timely transferred, and the heat accumulation can cause the advanced aging and damage of the electronic elements, so that the performance and the service life of instruments and equipment are influenced. Meanwhile, vibration extrusion accompanied by the mechanical electronic equipment in the operation process also puts new requirements on materials. The traditional heat conduction material has high density, high thermal expansion coefficient and no elasticity, is easy to damage and lose efficacy in the reciprocating extrusion process, and can not meet the requirement of future development. The carbon nano tube has ultrahigh thermal conductivity, elasticity and strength, and simultaneously has the properties of low density, chemical corrosion resistance, low thermal expansion and the like, and is the most potential heat conduction material in the future. Since carbon nanotubes are a one-dimensional nanomaterial, their thermal conductivities in various directions vary greatly. In many applications in the aspect of heat conduction, an isotropic high-heat-conduction three-dimensional bulk material is needed, and how to prepare a three-dimensional carbon material with excellent performance becomes a hotspot of modern scientific research.

At present, the carbon material is mainly used for preparing graphene, crystalline flake graphite, expanded graphite, carbon fiber and the like which are high-heat-conducting materials. The preparation of composite materials using three-dimensional structures of carbon nanotubes has attracted the attention of some researchers, and some patents have been issued or published. The publication No. CN104525120A is that the graphene and carbon nanotube composite material is obtained by mixing the carbon nanotube and the graphene oxide through liquid phase, and then solidifying and reducing the mixture, and the composite material is mainly used as an oil-absorbing foam material. CN104445173A describes a method for preparing a composite material of carbon nanotubes and graphene by hydrothermal reaction, in which carbon nanotubes and graphene oxide foam are mixed and then reduced to obtain the composite material, and the carbon nanotubes and graphene are connected by van der waals force, so the bonding force is poor, the mechanical properties are poor, and the material is easily damaged during compression, which cannot meet the practical application. Meanwhile, the prepared material has poor heat-conducting property due to the lack of connection among the nano-particles, and few research reports on how to prepare the high-heat-conducting carbon nano-tube three-dimensional composite material are reported.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a preparation method of a high-elasticity high-heat-conductivity three-dimensional carbon nanotube composite material, aiming at the problems that the porosity of a carbon nanotube sponge is large, the connection between a carbon tube and the carbon tube is short, the heat conductivity is poor, the connection part of the carbon tube is welded, and the preparation method of the three-dimensional carbon nanotube/copper composite material with isotropic heat conductivity and good compression resilience is prepared. The coefficient of thermal conductivity in all directions is not less than 2W/mK; meanwhile, the compression resilience is isotropic, and the rebound resilience after 50% compression is more than 95%.

The technical purpose of the invention is realized by the following technical scheme.

A preparation method of a three-dimensional carbon nanotube composite material with high elasticity and high heat conductivity is carried out according to the following steps:

step 1, dipping a carbon nano tube sponge in a copper sulfate solution to obtain a copper sulfate coated carbon nano tube sponge;

in the step 1, copper sulfate is uniformly dispersed in an organic solvent to form a copper sulfate solution, wherein the concentration of the copper sulfate is 0.1-0.5 g/ml; the organic solvent is N, N-dimethylformamide, N-dimethylacetamide or tetrahydrofuran.

In step 1, the impregnation is carried out in a vacuum environment to fully impregnate for 1-5 hours.

In step 1, drying the sample in an oven after dipping to obtain a copper sulfate coated carbon nanotube sponge, and drying for 20-24 hours at 80-100 ℃.

And 2, placing the copper sulfate coated carbon nano tube sponge body obtained in the step 1 into a tube furnace, heating to 600-700 ℃ from the room temperature of 20-25 ℃ at the heating rate of 1-10 ℃ per minute in the atmosphere of inert protective gas, carrying out heat preservation reaction to decompose copper sulfate to generate copper oxide particles, then cooling to 400-500 ℃ at the cooling rate of 1-10 ℃ per minute, carrying out heat preservation treatment by taking hydrogen and inert protective gas as the atmosphere to reduce copper oxide, converting the copper oxide into copper particles, and finally cooling to the room temperature of 20-25 ℃ along with the furnace.

In step 2, the inert protective gas is nitrogen, helium or argon.

In step 2, the temperature rise rate is 5-10 ℃ per minute.

In step 2, the cooling rate is 5-10 ℃ per minute.

In step 2, reacting at 600-700 deg.C for 30-90 min, preferably at 650-700 deg.C for 30-60 min.

In step 2, the reaction is carried out at 400-500 ℃ for 30-90 min, preferably at 450-500 ℃ and for 30-60 min.

In step 2, the flow rate of the hydrogen gas is 100 to 500sccm, the flow rate of the inert shielding gas is 100 to 500sccm, preferably the flow rate of the hydrogen gas is 100 to 300sccm, and the flow rate of the inert shielding gas is 100 to 300 sccm.

In the technical scheme of the invention, the carbon nano tube sponge body attached with copper sulfate is subjected to heat treatment in a tube furnace, firstly, the heat treatment is carried out at 600-700 ℃, so that the copper sulfate is decomposed to generate copper oxide particles, the copper sulfate is attached to the tube wall of the carbon nano tube, the copper oxide particles are also attached to the surface of the carbon tube, then, the heat treatment is carried out in the atmosphere of hydrogen and inert protective gas, the copper oxide is reduced to copper, and the copper particles on the surfaces of adjacent carbon tubes are fused because the copper particles are smaller, so that the effect of connecting the carbon tubes is achieved, and the copper plays a role in welding. Copper is plated on the surfaces of the carbon nanotubes through the steps, so that connecting points of copper are formed by the adjacent carbon nanotubes, the integrity and the stability of the carbon nanotube sponge are enhanced, and meanwhile, the joint connection is favorable for the transfer of heat among the carbon nanotubes, so that the heat conductivity of the carbon nanotube sponge is improved, an isotropic elastic heat-conducting composite material is obtained, the heat conductivity coefficient of the composite material is greater than 2W/mK, and the resilience rate of the composite material after 50% compression is more than 99%.

Compared with the prior art, the technical scheme of the invention uses copper sulfate as a copper source, uses the carbon nano tube sponge as a matrix, controls the attachment of copper sulfate liquid on the surface of the carbon nano tube, and then obtains the carbon nano tube/copper composite material through thermal reduction. According to the invention, the carbon nanotubes are mutually connected together through copper, so that the same heat conductivity and elasticity in all directions are obtained, and the heat conductivity and mechanical property of the sponge are obviously improved by the joint welding of the copper, namely the application of the method in improving the heat conductivity and rebound rate of the carbon nanotube sponge is realized.

Drawings

Fig. 1 is a schematic view of a process for preparing a three-dimensional carbon nanotube composite material according to the present invention.

Fig. 2 is an SEM photograph of a three-dimensional carbon nanotube composite welded using copper using the technical scheme of the present invention.

Detailed Description

The following examples of the present invention are given to further illustrate the present invention, but not to limit the scope of the present invention. The carbon nanotube sponge was prepared according to the references adv, mater, 2010,22, 617-621, and the heat conductivity was measured using a relaxation resistant LFA467 flash emission thermal conductivity meter and the resilience was measured using an electronic tensile tester.