Study of Interfacial Properties of Carbon Fiber Epoxy Matrix Composites Containing Graphene Nanoplatelets

Two-dimensional functionalized graphene nanoplatelets were incorporated in carbon fiber epoxy matrix composites to prepare a novel class of hierarchical composites. The nanoplatelets were coated on the surface of fibers by electrophoretic deposition prior to the preparation of composites. Later the nanoplatelet-deposited fibers were impregnated with epoxy resin by a combination of hand layup and vacuum bagging process. The composites were characterized microstructurally by spectroscopy, and optical and electron microscopy. The mechanical characterization was performed by flexural and interlaminar shear tests. It was observed that nanoplatelets possessed different functional groups responsible for making interactions with epoxy and carbon fibers. The flexural strength of composites increased by ~41 %, flexural modulus by ~26 % while interlaminar shear strength increased by ~24 %. The observation of the fractured surfaces of composites provided qualitative evidences of the improved interfacial adhesion. The enhancement in the properties is attributed to hydrogen bonding and mechanical interlocking of nanoplatelets with carbon fibers and epoxy resin. Electron microscopy revealed the retention of nanoplatelets on carbon fibers after manufacturing the composites. Such hierarchical composites are ideal candidate materials for improved through-thickness properties especially for futuristic aerospace structural applications.