Surface functionalization of thermoset composite for infrared hybrid welding

Fusion assembly is a highly promising technique for joining thermoplastic composite to thermoset composites, enabling the use of both the most affordable composite material and process for each substructure. However, some major challenges need to be addressed such as functionalizing the thermoset composite surface through co-curing with an appropriate thermoplastic interlayer or realizing a fast and robust welding process that meets all quality and mechanical requirements. In this paper, we investigated the potential of polyetheretherketone (PEEK) and its amorphous (PEEK A) and semicristalline (PEEK SC) states as interlayer materials, co-cured onto thermoset composites. A surface preparation involving the atmospheric plasma process demonstrated that both PEEK state materials can be used as interlayer with favorable adhesion properties. The influence of the plasma treatment on surface properties and morphology was also experimentally characterized.