两亲改性碳纤维制备质子交换膜燃料电池用碳纸的研究

Study on Preparation of Carbon Paper for Proton Exchange Membrane Fuel Cell by Amphiphilic Modified Carbon Fibers

为了提高短切碳纤维在水中的分散性及碳纤维与后期浸渍树脂的相容性,对碳纤维进行了两亲表面处理:首先通过氧化处理使其获得亲水性官能团-OH及-COOH,在此基础上进一步接枝亲油基团,以获得两亲碳纤维,并将其制备碳纸。结果表明,两亲处理的碳纤维表面-OH含量可达8. 2%。在碳纤维表面改性过程中,铬酸氧化在提高碳纤维表面亲水性官能团的同时会降低碳纸的抗张强度;而接枝亲油性官能团能提高碳纤维与树脂的黏结能力,部分弥补了表面处理所造成的负面影响;碳纤维与树脂黏结力的提高有利于碳纸导电性的提高,两亲改性碳纤维制备的碳纸与未处理碳纤维制备碳纸相比电阻率降低了31. 4%,达到10. 5 mΩ·cm。

In order to improve the dispersibility of short carbon fibers in water and the compatibility of the carbon fibers with the impregnating resin,the carbon fibers were subjected to multiple surface treatments. Firstly,some hydrophilic groups were treated on the surface of carbon fibers by oxidation treatment. Furthermore,the carbon fibers grafted lipophilic functional groups with part of hydrophilic functional groups,obtained the amphiphilic modified carbon fiber and carbon paper. The results showed that the surface of amphiphilic carbon fibers had the hydroxyl content of 8. 2%. In the process of carbon fiber surface modification,chromic acid oxidation increased the hydrophilic group on the surface of carbon fiber while reduced the tensile strength of carbon papers. The lipophilic functional groups were beneficial to the bonding between carbon fibers and the resin. The improvement of bonding strength partially compensated for the negative effects caused by the oxidation surface treatment. The adhesion between the carbon fibers and the resins was favorable for the conductivity of the amphiphilic modification carbon papers. The resistivity was reduced by 31. 4% compare to untreated carbon paper,and reached to 10. 5 mΩ·cm.