Assessment of Interfacial Interaction in Graphene Nanoplatelets and Carbon Fiber-Reinforced Epoxy Matrix Multiscale Composites and Its Effect on Mechanical Behavior

Delamination and fiber pull-out remain significant problems with carbon fiber-reinforced epoxy composites due to the brittle nature of epoxy and weak fiber–matrix interface. The present study approaches overcome these problems by fabricating a multiscale carbon fiber-epoxy composites laminated composite with graphene nanoplatelets reinforced matrix, using a vacuum-assisted resin infusion method. Incorporation of 0.2 wt.% graphene nanoplatelets in carbon fiber-reinforced epoxy composites enhances fracture toughness by ~ 35% and ultimate tensile strength by ~ 22%, owing to significant adhesion between fiber and matrix. Thorough fiber–matrix interfacial characterization revealed improved modulus gradient across the interface, ~ 38% more energy absorption during delamination, and ~ 42% higher fiber pull-out strength from the matrix.