Effects of low-pressure plasma surface modification on the surface properties of carbon fibers

Carbon fiber reinforced polymer (CFRP) composites are widely used in industrial applications due to their high specific strength and stiffness. However, the interfacial bonding between carbon fibers (CFs) and polymer matrices is often inadequate because of the chemical inertness and low surface energy of CFs. In this study, low-pressure plasma treatment was employed to enhance the interfacial adhesion between CFs and Polyetheretherketone (PEEK), with the underlying mechanism systematically investigated. Results demonstrate that the treatment significantly improves the interfacial shear strength (IFSS) by 36.0% at the optimal 3-minute exposure duration. Meanwhile, the CF/PEEK composites exhibited significantly enhanced mechanical properties. This enhancement is attributed to the increased oxygen-containing functional groups on fiber surfaces, and augmented surface roughness, as confirmed by XPS, SEM and AFM analyses.