Uniform modification of carbon fibers surface in 3-D fabrics using intermittent electrochemical treatment

An intermittent electrochemical treatment method was developed in this work which was used to modify the surface of carbon fibers in three-dimensional fabrics. The effects of this treatment on the surface chemical components of the fibers in both interior and surface regions of the fabrics were analyzed by X-ray photoelectron spectroscopy. The wettability of the fabrics was evaluated by liquid-drop method. A microdebonding method was employed to determine the uniformity of interfacial shear strength between the fibers and the matrix in different regions of the carbon fabric/phenolic composites. The compressive strength was also tested to evaluate the effects of treatment. The results indicated that the intermittent electrochemical treatment significantly improved the interfacial adhesion by etching and generating oxygenic and nitrogenous functional groups. The processibility of the fabrics was also improved due to improved impregnation of phenolic resin with the fabrics. The compressive strength was significantly increased due to optimized intermittent electrochemical treatment. Moreover, comparing with the traditional continuous electrochemical treatment which the treatment degrees of the fibers in different region of the fabrics were different, the intermittent treatment was a useful method to obtain the relatively uniform properties throughout the fabrics.