Method for modifying high-performance carbon paper based on supercritical fluid technology

Abstract

The invention discloses am ethod for modifying high-performance carbon paper based on supercritical fluid technology. Under the action of the supercritical fluid, O2 and a titanate coupling agent are used for cooperatively modifying the carbon fibers, on one hand, the oxidation time can be shortened, the roughness and oxygen-containing groups of the surfaces of the carbon fibers can be improved, the surfaces of the carbon fibers are more effectively wetted, and uniform surface modification is achieved; and on the other hand, the titanate coupling agent has molecules with two groups with different properties, so that the defect that the modification effect of a single titanate coupling agent is not obvious because the number and the variety of oxygen-containing functional groups on the surface of the carbon fiber are relatively small can be overcome, and the mechanical property and the conductivity of the carbon paper are improved.

Description

technical field [0001] The invention relates to a method for modifying high-performance carbon paper based on supercritical fluid technology, which belongs to the field of fuel cells. Background technique [0002] A fuel cell is a device that directly converts chemical energy into electrical energy. The gas diffusion layer is composed of a conductive porous material, which plays multiple roles such as supporting the catalytic layer, conducting electrons, mass transfer, heat transfer, and discharging water. It affects the performance of the electrode. one of the key components. Carbon paper is the most common gas diffusion layer substrate material, which has a uniform porous thin layer structure, good thermal and electrical conductivity, stable size, and good mechanical strength. [0003] Carbon paper is usually prepared by wet papermaking process, using carbon fiber as raw material through wet papermaking, resin impregnation, hot pressing curing, carbonization and graphitiz...

AI Technical Summary

Problems solved by technology

[0011] In order to solve at least one of the above-mentioned technical problems, the present invention provides a method for modifying high-performance carbon paper using supercritical fluid technology. In supercritical fluid, O2 and titanate coupling agents are used to synergistically modify carbon fibers. It utilizes the characteristics of supercritical fluid’s strong penetration ability and intense molecular movement. On the one hand, it can reduce the oxidation time, reduce the difficulty of controlling the depth of gas-phase oxidation without destroying the strength of the carbon fiber body, and improve the surface roughness and content of the carbon fiber. Oxygen groups can more effectively wet the surface of carbon fibers to achieve uniform surface modification; on the other hand, the oxidized carbon fibers are modified by coupling agents, because titanate coupling agents have two different properties One end of the molecule of the group can form a chemical bond with the oxygen-containing active group on the surface of the carbon fiber, and the other end can react with the phenolic resin group to endow the resin with a certain degree of toughness. Less, the single titanate coupling agent modification effect is not obvious, improve the interfacial bonding force between carbon fiber and resin, thereby improving the mechanical properties and electrical conductivity of carbon paper

Images