Co-cure joining of epoxy composites with rapidly UV-irradiated PEEK and PPS composites to achieve high structural integrity

Efficient joining of hybrid thermoset/thermoplastic composite joints is critical to produce high performance lightweight structures while keeping the cost low. Herein, a high‐power UV‐irradiation technique was pro- posed to rapidly active the surfaces of PEEK and PPS composites for the following co‐cure joining with epoxy composites. A single lap‐shear joint test and a double cantilever beam test were used to evaluate the mechan- ical and fracture performance of the hybrid joints. The experimental results revealed that high structural integ- rity of the hybrid joints was achieved upon applying a 6 s UV‐treatment to the thermoplastic composites. For example, the lap‐shear strength and fracture energy of the adhesive bonded hybrid joints were above 25 MPa and 800 J/m2, respectively. Overall, high‐power UV‐irradiation proved a highly efficient, rapid and low‐cost method to treat thermoplastic composites for the co‐cure joining with epoxy composites, and hence it demon- strated significant promise in industrial mass production.