Comparing the properties of commercially treated and air plasma treated carbon fibers

Abstract Carbon fibers undergo aqueous electrolytic oxidation during manufacturing to remove surface graphitic layers. Significant cost reduction and lower environmental impact could however be achieved by replacing electrolytic oxidation with a dry process, such as plasma treatment. This study demonstrates how air plasma treatment can be used as a dry surface modification process for carbon fibers, thus aiding in the understanding of the influence of surface treatment on surface chemistry, mechanical properties and fiber-matrix interactions. Greater oxygen incorporation resulted from electrolytic oxidation than air plasma treatment but had similar interfacial shear strengths, indicating that chemistry may have less of an effect on fiber-matrix adhesion than previously suggested. The removal of weakly bound surface graphitic layers and increases in surface roughness, which were achieved by both methods, appear to be the most important factors influencing fiber-matrix adhesion, thereby suggesting that dry plasma treatment could replace the current wet processing.