Improving the Bonding Strength of CFRP by Atmospheric Pressure Plasma Jet

Carbon fiber reinforced polymer (CFRP) has been widely used in recent years due to their excellent mechanical properties, especially in aerospace and automotive fields. However, the low bonding strength of the CFRP due to its low surface energy restrains its industrial applications. Although methods including mechanical treatment, laser treatment, flame treatment and chemical treatment have been proposed to improve the bonding strength, the methods tend to involve dangerous chemical reagents, or may induce serious structural damages. In this study, we propose to use atmospheric pressure plasma jet (APPJ) to improve the surface wettability and bonding strength of the CFRP. Contact angles of water and epoxy resin, surface chemical composition, and microstructures before and after the APPJ treatments are characterized. Results indicate that the APPJ treatment can effectively improve surface wettability and bonding strength of the CFRP. The water contact angle decreases from ∼86° to ∼15.2°, while the shear strength increases from ∼5.5 MPa to ∼26.9 MPa, indicating that the APPJ may be a promising candidate for treatment of CFRP surfaces.