Environmental impact investigation on the interlaminar properties of carbon fibre composites modified with graphene nanoparticles

Abstract

Graphene nanoparticles have been widely studied for their all-round promising positive effects. In this study, the effect of adding functionalised 2% NH2-graphene nanoparticles to carbon fibre/epoxy composite was assessed, before and after hygrothermal and ultraviolet exposure. The interlaminar shear strength and glass transition temperature of the filled and unfilled were experimentally determined, after being immersed in water at 25 °C, 40 °C and 70 °C until partially saturated. Other samples were exposed to ultraviolet for 700 and 1400 h. With graphene, samples showed up to 43.9% better water uptake resistance. The interlaminar shear strength decreased after immersion in water by an average of 5.8% with graphene, however, after ultraviolet exposure the ILSS loss commonly attributed to UV exposure was reduced by 12.1% with graphene. This improvement can be explained by the GNPs offering stability against free-radical ageing, slowing the rate of scissions and the eventual transformation to constituent monomers. Dynamical mechanical analysis on immersed samples showed that the graphene reduced glass transition temperature by only 1%. Filled samples exposed to UV for 1400 h suggested a reduction in glass transition temperature of 1 °C. Scanning electron microscopy revealed good dispersion of the GNPs in the epoxy matrix but with no strong bonding. • Graphene in carbon fibre had vast improvements to water uptake resistance of 43.9%. • Graphene improved strength resistance considerably after UV exposure by 12.1%. • Interlaminar shear strength decreased by 5.8% with graphene due to poor bonding.