Evaluation of fiber surface treatment on the interfacial behavior of carbon fiber-reinforced polypropylene composites

Carbon fiber reinforced polypropylene (CFRPP) has been widely used in many engineering fields because of its high specific strength and stiffness. However, polypropylene (PP) does not adhere well with carbon fibers because it has a low free surface energy. In addition, high viscosity in the melted phase causes poor impregnation. In this study, surface treatment methods, i.e., coupling agents with plasma treatment on carbon fibers, were applied to increase the interfacial strength between the carbon fibers and the PP matrix. The modified carbon fiber surfaces were analyzed by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). To analyze the effectiveness of the surface treatment method, the interlaminar shear strength (ILSS) was measured using the three points bending test. From the test results, the ILSS of the specimens treated with the silane coupling agent after the plasma treatment increased by 48.7% compared to those of the untreated specimens.