阅读说明：本技术 碳纤维纸的制备方法 (Preparation method of carbon fiber paper ) 是由 陈辉 沈志刚 李磊 于 2019-10-24 设计创作，主要内容包括：本发明涉及一种碳纤维纸的制备方法,特别是涉及一种低成本、导电和机械性能良好、可用于质子交换膜燃料电池气体扩散层的碳纤维纸的制备方法,主要解决现有技术中存在的碳纤维活化过程耗时耗能、条件不易控制、效果不显著的问题。采用一种碳纤维纸的制备方法,包括以下步骤：1)将经短切、脱胶后的碳纤维,在辐照介质中进行辐照处理,辐照剂量率为10～10000Gy/s,辐照总剂量为10～2000kGy；2)将经辐照处理得到的碳纤维中加入分散剂和粘合剂,采用湿法造纸技术制成碳纤维纸前驱体；然后用热固性酚醛树脂进行浸渍,再经固化、碳化,制得所述碳纤维纸的技术方案,较好地解决了该问题,可用于碳纤维纸的工业生产中。(The invention relates to a preparation method of carbon fiber paper, in particular to a preparation method of carbon fiber paper which has low cost, good electric conductivity and mechanical property and can be used for a gas diffusion layer of a proton exchange membrane fuel cell, and mainly solves the problems that the activation process of carbon fiber in the prior art consumes time and energy, the condition is not easy to control and the effect is not obvious. The preparation method of the carbon fiber paper comprises the following steps: 1) carrying out irradiation treatment on the chopped and degummed carbon fibers in an irradiation medium, wherein the irradiation dose rate is 10-10000 Gy/s, and the total irradiation dose is 10-2000 kGy; 2) adding a dispersing agent and an adhesive into the carbon fiber obtained by irradiation treatment, and preparing a carbon fiber paper precursor by adopting a wet papermaking technology; then impregnating with thermosetting phenolic resin, curing and carbonizing to obtain the carbon fiber paper.)

1. A preparation method of carbon fiber paper comprises the following steps:

1) carrying out irradiation treatment on the chopped and degummed carbon fibers in an irradiation medium, wherein the irradiation dose rate is 10-10000 Gy/s, and the total irradiation dose is 10-2000 kGy;

2) adding a dispersing agent and an adhesive into the carbon fiber obtained by irradiation treatment, and preparing a carbon fiber paper precursor by adopting a wet papermaking technology; then, thermosetting phenolic resin is used for impregnation, and the carbon fiber paper is prepared after curing and carbonization.

2. The method for preparing carbon fiber paper according to claim 1, wherein the carbon fiber is one or more of polyacrylonitrile-based carbon fiber and pitch-based carbon fiber.

3. The method for producing a carbon fiber paper according to claim 1, wherein the carbon fiber has a resistivity of 0.001 to 0.01 Ω -cm.

4. The method for preparing carbon fiber paper according to claim 1, wherein the length of the chopped carbon fiber is 3-18 mm.

5. The method for preparing carbon fiber paper according to claim 1, wherein the degumming process is extraction in an organic solvent; the organic solvent is preferably one or a mixture of two of acetone and ethanol.

6. The process for the preparation of carbon fiber paper according to claim 1, characterized in that the irradiation medium is air, nitrogen, argon, helium, epichlorohydrin, preferably epichlorohydrin.

7. The method for producing a carbon fiber paper according to claim 1, characterized in that the temperature of the irradiation treatment is 60 ℃ or lower; the irradiation treatment time is less than or equal to 120 min.

8. The method for preparing carbon fiber paper according to claim 1, wherein the dispersant is one or a combination of two or more of polyacrylamide, methylcellulose, sodium hydroxymethylcellulose, or hydroxyethylcellulose.

9. The method for preparing carbon fiber paper according to claim 1, wherein the binder is one or a combination of two or more of polyvinyl alcohol and phenolic resin.

10. A carbon fiber paper produced by the production method according to any one of claims 1 to 9.

Technical Field

The invention relates to a preparation method of carbon fiber paper, in particular to a preparation method of carbon fiber paper which has low cost and good electric conduction and mechanical properties and can be used for a gas diffusion layer of a proton exchange membrane fuel cell.

Technical Field

Proton Exchange Membrane Fuel Cells (PEMFCs) have the characteristics of high power density, high energy conversion rate, low-temperature start, no pollution, light volume, and the like, and can be used as uninterruptible power supplies and decentralized power stations for power systems of vehicles, mobile small power supply systems and electronic devices, and emergency power supplies for military, medical, entertainment places, and the like. The PEMFC also permeates all industries and even ordinary families in the society, and has important significance for industrial structure upgrading, environmental protection and economic sustainable development.

The key components of the PEMFC are membrane Electrode three-in-one assemblies (MEA), which comprises: proton exchange membrane, catalyst layer, gas diffusion layer. The gas diffusion layer serves to support the catalyst layer, stabilize the electrode structure, and also provide gas channels, electron channels, and water discharge channels for electrode reactions. The gas diffusion layer is generally composed of a substrate layer and a microporous layer, and the substrate layer is generally made of carbon fiber paper (carbon paper), carbon cloth, nonwoven cloth, and carbon black paper. High performance carbon fiber paper has been widely used as a gas diffusion layer of PEMFCs. The carbon fiber paper has a porous structure, good permeability, good electrical conductivity, good chemical stability, high temperature resistance, corrosion resistance and high heat conductivity, and can meet the working environment of the fuel cell.

The conventional method for preparing the carbon fiber paper is to prepare porous carbon fiber base paper by dispersing and bonding chopped carbon fibers, and then form interconnected carbon matrixes on the surfaces of the fibers by a dipping carbonization process to obtain the final carbon fiber paper. The carbon fiber is different from plant fiber, the surface of the carbon fiber only contains a small amount of groups, only can produce cutting effect in the beating process, can not produce devillicate brooming phenomenon, and can not produce hydrogen bond among fibers after paper sheet forming. The problems different from plant fibers are solved in the paper-making process of the carbon fibers, and mainly focus on two aspects of dispersion and paper-making strength of the carbon fibers. High-performance carbon fiber paper generally puts higher requirements on purity, uniformity, resistivity, porosity and the like. In the production of high-purity carbon fiber paper, because the content of other sizing agents is low, the problems of dispersion and forming of carbon fibers are more prominent, and the production process is more complicated. In addition, the subsequent carbonization and graphitization process is a time-consuming and energy-consuming process, and directly determines the conductivity of the subsequent product.

Irradiation is a chemical technology for changing the molecular structure by utilizing radiation of radioactive elements, and can industrially modify macromolecules to form a network structure, thereby enhancing the thermal stability, flame retardance, chemical stability and the like of materials.

The activation of carbon fiber by the existing technical scheme of carbon fiber paper is limited to the traditional oxidation method, the effect is not obvious, and the subsequent carbonization and graphitization process consumes time and energy (CN108914681A, CN 106436439A). By carrying out irradiation treatment on the short carbon fibers, the invention solves the problems of poor dispersibility of the carbon fibers in water, poor uniformity of carbon paper and time and energy consumption in carbonization and graphitization in the prior art, and makes up for the defects in the prior art.

Disclosure of Invention

One of the main technical problems to be solved by the invention is the problems of time and energy consumption, difficult control of conditions and insignificant effect in the activation process of the carbon fiber in the prior art. The preparation method of the carbon fiber paper has the characteristics of low energy consumption, simple and convenient operation, easy control and good treatment effect.

The second technical problem to be solved by the invention is to provide a carbon fiber paper prepared by the preparation method corresponding to the first technical problem.

In order to solve one of the above technical problems, the technical scheme adopted by the invention is as follows: a preparation method of carbon fiber paper comprises the following steps:

1) carrying out irradiation treatment on the chopped and degummed carbon fibers in an irradiation medium, wherein the irradiation dose rate is 10-10000 Gy/s, and the total irradiation dose is 10-2000 kGy;

2) adding a dispersing agent and an adhesive into the carbon fiber obtained by irradiation treatment, and preparing a carbon fiber paper precursor by adopting a wet papermaking technology; then, thermosetting phenolic resin is used for impregnation, and the carbon fiber paper is prepared after curing and carbonization.

In the technical scheme, the carbon fiber is one or more than two of polyacrylonitrile-based carbon fiber and asphalt-based carbon fiber.

In the technical scheme, the resistivity of the carbon fiber is 0.001-0.01 omega cm.

In the technical scheme, the length of the chopped carbon fiber is 3-18 mm.

In the technical scheme, the degumming process is extraction in an organic solvent; the organic solvent is preferably one or a mixture of two of acetone and ethanol.

In the technical scheme, the irradiation medium is air, nitrogen, argon, helium or epoxy chloropropane; preferably epichlorohydrin, the inventors have surprisingly found that this preferred embodiment allows carbon fiber papers to be obtained with higher tensile strength and lower sheet resistance.

In the technical scheme, the temperature of the irradiation treatment is less than or equal to 60 ℃; the irradiation treatment time is less than or equal to 120 min.

In the technical scheme, the dispersing agent is one or the combination of more than two of polyacrylamide, methylcellulose, sodium carboxymethylcellulose or hydroxyethyl cellulose.

In the above technical scheme, the adhesive is one or a combination of more than two of polyvinyl alcohol and phenolic resin.

In the above technical solution, the radiation source is not particularly limited, and may be a radiation source commonly used in the art, for example, but not limited to, gamma rays or electron beams.

In order to solve the second technical problem, the invention adopts the technical scheme that: a carbon fiber paper is prepared by the preparation method in any one of the technical schemes for solving the technical problems.

According to the invention, the short carbon fibers are subjected to irradiation treatment in a special irradiation medium, so that the problems of poor dispersibility of the carbon fibers in water, poor uniformity of carbon paper and time and energy consumption in carbonization and graphitization in the prior art are solved, and the defects in the prior art are overcome.

By adopting the technical scheme, the carbon fibers are chopped and degummed, and then are subjected to irradiation treatment in a specific medium, wherein the irradiation dose rate is 10-10000 Gy/s, and the total irradiation dose is 10-2000 KGy; adding a dispersing agent and an adhesive, and preparing a carbon fiber paper precursor by a conventional wet papermaking technology; then, impregnating the mixture with thermosetting phenolic resin, and curing the mixture at a certain temperature and pressure; and finally carbonizing the paper at 800-1500 ℃ for 0.5 hour to obtain the final carbon fiber paper product. Final carbon fiber paper properties: the tensile strength is more than 15MPa, the surface resistance is less than 8.0m omega cm, the tensile strength of the preferred scheme is more than 30MPa, and the surface resistance is less than 6.0m omega cm, thereby obtaining better technical effect.

The invention is further illustrated by the following specific examples.

Detailed Description

[ example 1 ]

Chopping and degumming carbon fibers, and then irradiating the carbon fibers in an air atmosphere at the irradiation dose rate of 10Gy/s, the irradiation time of 1000s, the total irradiation dose of 10kGy and the irradiation temperature of 20 ℃. Then adding a dispersant and a binder, and preparing a carbon fiber paper precursor by a conventional wet papermaking technology (defibering, pulping, papermaking and drying); then, impregnating the mixture with thermosetting phenolic resin, and curing the mixture at the temperature of 150 ℃ and under the hot-pressing pressure of 5 MPa; and finally carbonizing the paper at 800-1500 ℃ for 0.5 hour to obtain the final carbon fiber paper product. The tensile strength (GB _ T20042.7-2014 proton exchange membrane fuel cell part 7 carbon paper characteristic test method) is 17MPa, and the surface resistance (GB _ T20042.7-2014 proton exchange membrane fuel cell part 7 carbon paper characteristic test method) is 7.5m omega cm.

[ example 2 ]

Chopping and degumming carbon fibers, and then irradiating the carbon fibers in an air atmosphere, wherein the irradiation dose rate is 1000Gy/s, the irradiation time is 2000s, the total irradiation dose is 2000kGy, and the irradiation temperature is 20 ℃. Then adding a dispersing agent and an adhesive, and preparing a carbon fiber paper precursor by a conventional wet papermaking technology; then, impregnating the mixture with thermosetting phenolic resin, and curing the mixture at the temperature of 150 ℃ and under the hot-pressing pressure of 5 MPa; and finally carbonizing the paper at 800-1500 ℃ for 0.5 hour to obtain the final carbon fiber paper product. Tensile strength of 22MPa and surface resistance of 6.3m omega cm.

[ example 3 ]

Chopping and degumming carbon fibers, and then irradiating the carbon fibers in an air atmosphere, wherein the irradiation dose rate is 1000Gy/s, the irradiation time is 1000s, the total irradiation dose is 1000kGy, and the irradiation temperature is 20 ℃. Then adding a dispersing agent and an adhesive, and preparing a carbon fiber paper precursor by a conventional wet papermaking technology; then, impregnating the mixture with thermosetting phenolic resin, and curing the mixture at the temperature of 150 ℃ and under the hot-pressing pressure of 5 MPa; and finally carbonizing the paper at 800-1500 ℃ for 0.5 hour to obtain the final carbon fiber paper product. Tensile strength 24MPa, surface resistance 6.7m omega cm.

[ example 4 ]

Chopping and degumming carbon fibers, and then irradiating the carbon fibers in an air atmosphere at the irradiation dose rate of 10000Gy/s, the irradiation time of 1s, the total irradiation dose of 10kGy and the irradiation temperature of 20 ℃. Then adding a dispersing agent and an adhesive, and preparing a carbon fiber paper precursor by a conventional wet papermaking technology; then, impregnating the mixture with thermosetting phenolic resin, and curing the mixture at the temperature of 150 ℃ and under the hot-pressing pressure of 5 MPa; and finally carbonizing the paper at 800-1500 ℃ for 0.5 hour to obtain the final carbon fiber paper product. The tensile strength is 16MPa, and the surface resistance is 7.8m omega cm.

[ example 5 ]

Chopping and degumming carbon fibers, and then irradiating the carbon fibers in an air atmosphere, wherein the irradiation dose rate is 1000Gy/s, the irradiation time is 200s, the total irradiation dose is 200kGy, and the irradiation temperature is 20 ℃. Then adding a dispersing agent and an adhesive, and preparing a carbon fiber paper precursor by a conventional wet papermaking technology; then, impregnating the mixture with thermosetting phenolic resin, and curing the mixture at the temperature of 150 ℃ and under the hot-pressing pressure of 5 MPa; and finally carbonizing the paper at 800-1500 ℃ for 0.5 hour to obtain the final carbon fiber paper product. Tensile strength is 25MPa, and surface resistance is 6.5m omega cm.

[ example 6 ]

Chopping and degumming carbon fibers, and then irradiating the carbon fibers in an air atmosphere at the irradiation dose rate of 10000Gy/s, the irradiation time of 20s, the total irradiation dose of 200kGy and the irradiation temperature of 20 ℃. Then adding a dispersing agent and an adhesive, and preparing a carbon fiber paper precursor by a conventional wet papermaking technology; then, impregnating the mixture with thermosetting phenolic resin, and curing the mixture at the temperature of 150 ℃ and under the hot-pressing pressure of 5 MPa; and finally carbonizing the paper at 800-1500 ℃ for 0.5 hour to obtain the final carbon fiber paper product. Tensile strength 23MPa, surface resistance 6.6m omega cm.

[ example 7 ]

Chopping and degumming carbon fibers, and then irradiating the carbon fibers in an air atmosphere, wherein the irradiation dose rate is 1000Gy/s, the irradiation time is 100s, the total irradiation dose is 100kGy, and the irradiation temperature is 20 ℃. Then adding a dispersing agent and an adhesive, and preparing a carbon fiber paper precursor by a conventional wet papermaking technology; then, impregnating the mixture with thermosetting phenolic resin, and curing the mixture at the temperature of 150 ℃ and under the hot-pressing pressure of 5 MPa; and finally carbonizing the paper at 800-1500 ℃ for 0.5 hour to obtain the final carbon fiber paper product. Tensile strength 21MPa, surface resistance 6.9m omega cm.

[ example 8 ]

Chopping and degumming carbon fibers, and then irradiating the carbon fibers in a nitrogen atmosphere at the irradiation dose rate of 1000Gy/s, the irradiation time of 200s, the total irradiation dose of 200kGy and the irradiation temperature of 20 ℃. Then adding a dispersing agent and an adhesive, and preparing a carbon fiber paper precursor by a conventional wet papermaking technology; then, impregnating the mixture with thermosetting phenolic resin, and curing the mixture at the temperature of 150 ℃ and under the hot-pressing pressure of 5 MPa; and finally carbonizing the paper at 800-1500 ℃ for 0.5 hour to obtain the final carbon fiber paper product. Tensile strength 23MPa, surface resistance 6.2m omega cm.

[ example 9 ]

Chopping and degumming carbon fibers, then irradiating in epichlorohydrin, wherein the irradiation dose rate is 1000Gy/s, the irradiation time is 200s, the total irradiation dose is 200kGy, and the irradiation temperature is 20 ℃. Then adding a dispersing agent and an adhesive, and preparing a carbon fiber paper precursor by a conventional wet papermaking technology; then, impregnating the mixture with thermosetting phenolic resin, and curing the mixture at the temperature of 150 ℃ and under the hot-pressing pressure of 5 MPa; and finally carbonizing the paper at 800-1500 ℃ for 0.5 hour to obtain the final carbon fiber paper product. Tensile strength 31MPa, surface resistance 5.5m omega cm.

[ example 10 ]

Chopping and degumming carbon fibers, then irradiating in epichlorohydrin, wherein the irradiation dose rate is 10000Gy/s, the irradiation time is 20s, the total irradiation dose is 200kGy, and the irradiation temperature is 20 ℃. Then adding a dispersing agent and an adhesive, and preparing a carbon fiber paper precursor by a conventional wet papermaking technology; then, impregnating the mixture with thermosetting phenolic resin, and curing the mixture at the temperature of 150 ℃ and under the hot-pressing pressure of 5 MPa; and finally carbonizing the paper at 800-1500 ℃ for 0.5 hour to obtain the final carbon fiber paper product. Tensile strength of 30MPa and surface resistance of 5.7m omega cm.

[ COMPARATIVE EXAMPLE 1 ]

And chopping and degumming the carbon fiber. Then adding a dispersing agent and an adhesive, and preparing a carbon fiber paper precursor by a conventional wet papermaking technology; then, impregnating the mixture with thermosetting phenolic resin, and curing the mixture at the temperature of 150 ℃ and under the hot-pressing pressure of 5 MPa; and finally carbonizing the paper at 800-1500 ℃ for 0.5 hour to obtain the final carbon fiber paper product. The tensile strength is 8MPa, and the surface resistance is 12.0m omega cm.

[ COMPARATIVE EXAMPLE 2 ]

Chopping and degumming carbon fibers, and then irradiating the carbon fibers in an air atmosphere at the irradiation dose rate of 10000Gy/s, the irradiation time of 1000s, the total irradiation dose of 10000kGy and the irradiation temperature of 20 ℃. Then adding a dispersing agent and an adhesive, and preparing a carbon fiber paper precursor by a conventional wet papermaking technology; then, impregnating the mixture with thermosetting phenolic resin, and curing the mixture at the temperature of 150 ℃ and under the hot-pressing pressure of 5 MPa; and finally carbonizing the paper at 800-1500 ℃ for 0.5 hour to obtain the final carbon fiber paper product. Tensile strength is 7MPa, and surface resistance is 6.7m omega cm.

[ COMPARATIVE EXAMPLE 3 ]

Chopping and degumming carbon fibers, then irradiating in epichlorohydrin at an irradiation dose rate of 10Gy/s, an irradiation time of 100s, a total irradiation dose of 1kGy and an irradiation temperature of 20 ℃. Then adding a dispersing agent and an adhesive, and preparing a carbon fiber paper precursor by a conventional wet papermaking technology; then, impregnating the mixture with thermosetting phenolic resin, and curing the mixture at the temperature of 150 ℃ and under the hot-pressing pressure of 5 MPa; and finally carbonizing the paper at 800-1500 ℃ for 0.5 hour to obtain the final carbon fiber paper product. Tensile strength 9MPa, surface resistance 10.5m omega cm.

Obviously, by adopting the technical scheme of the invention, the short carbon fibers are subjected to irradiation treatment, so that the problems of poor dispersibility of the carbon fibers in water, poor uniformity of carbon paper and time and energy consumption in carbonization and graphitization in the prior art are solved, the defects of the prior art are overcome, and the method can be used in the industrial production of carbon fiber paper.