Void reduction in graphene interlayer enhanced carbon fibre thermoplastic composites

Abstract

Graphene enhanced CF/PEEK composites are excellent candidates for aerospace applications where enhanced conductivity is integral, however including nanomaterials within the composite can also cause mechanical degradation, notably void formation. Surfactant stabilised graphene suspensions were used to generate graphene thin films for enhancing the interlaminar spaces in CF/PEEK. The presence of voids and mechanical strength was investigated with F108 and F68 surfactants and heat treatment of the thin film before hot pressing or hot embossing consolidation. Pluronic F68 yielded 3-4 layer graphene compared to F108, and when hot pressed had a 22% increase in shear strength compared to the control. The heat treated then hot pressed F108 graphene sample had the lowest void percentage of 1.7vol%. Heat treatment of thin films to remove excess surfactant combined with F68 surfactant will likely yield low void defect graphene enhanced CF/PEEK composites.