Enhanced Carbon/Epoxy Composite Fracture Toughness Achieved Using Atmospheric Pressure Plasma Treatments

Composite materials are used in a wide range of industry sectors including automobiles, aeronautics and sports equipment. Two types of composite joints, co-cured and secondary bonded joints are used in the industries. Co-curing of composite joints is an efficient and cost-effective method of joining composites. The objective of this research is to enhance the bond strength between the composite material and adhesive, specifically in this study the bond between carbon-epoxy prepregs and an epoxy adhesive. The research investigated how the use of atmospheric plasma treatments of the uncured composite prepreg influenced the fracture toughness of the co-cured composite joints. The use of atmospheric pressure plasma treatment in the surface activation of prepregs was examined using contact angle measurements and X-ray photoelectron microscopy (XPS). Failure mechanism of the co-cured composite joints was studied by double cantilever beam (DCB) tests. Composite interface morphology was examined by scanning electron microscopy (SEM/FIB).