Two-step surface treatment of 3D braided carbon/Kevlar hybrid fabric and influence on mechanical performance of its composites

Fiber surface treatment is crucial to the properties of fiber composites. The same mechanism applies to hybrid fiber composites. In this work, a two-step surface treatment was conducted on unidirectional and three-dimensional (3D) braided carbon/Kevlar hybrid fibers, and mechanical properties of the resulting composites were evaluated. Hybrid effect of the composites with varying fiber–matrix interfacial bonding was assessed. It was found that the hybrid composites showed significant improvements in flexural strength and interfacial adhesion strength (IAS) after two-step surface treatment, suggesting this process was efficient. Furthermore, the two-step surface treated carbon/Kevlar hybrid fibers-reinforced composite showed a positive hybrid effect on flexural strength, indicating the existence of hybrid effect is related to the nature of fiber–matrix interface.