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).