X-ray photoelectron spectroscopic studies of carbon fiber surfaces. 22. Comparison between surface treatment of untreated and previously surface-treated fibers

IM7 PAN-based carbon fibers, with a proprietary surface treatment applied by the manufacturer, were analyzed by X-ray photoelectron spectroscopy (XPS). The surface treatment applied by the manufacturer was removed by heating in a vacuum. The fibers detreated in this manner were then subjected to electrochemical treatment. The electrochemical behavior of the as-received fibers and detreated fibers were measured and analyzed. When the same electrochemical treatment was applied to the as-received fibers with their commercial surface treatment intact, a different surface chemistry was observed for the detreated fibers. This study shows that the surface chemistry of treated fibers depends closely on the initial surface chemistry of the fibers and its detreatment. This work shows the importance of using untreated or detreated fibers as precursors for applying reproducible surface treatment so that one can understand and control the surface chemistry of fibers and their interfacial interaction in composites.