Surface modification of PEEK by UV irradiation for direct co-curing with carbon fibre reinforced epoxy prepregs

Adding a layer of thermoplastic resin on the surface of thermoset composites enables welding as a possible joining method for thermoset composites. Adhesion at the thermoset/thermoplastic interface was achieved by direct co-curing of an UV irradiation treated PEEK film with aerospace grade carbon/epoxy prepregs. The effectiveness of UV irradiation for surface modification of PEEK was characterized Using Fourier-Transformed InfraRed (FTIR) spectroscopy and contact angle measurement. The adhesion quality at the thermoset/thermoplastic interface was evaluated using a double cantilever beam test and Atomic Force Microscopy (AFM). UV treatment was found to effectively modify the chemical structure of PEEK surface and improve the wettability, which enables the development of a thermoset/thermoplastic interface by direct co-curing.