Processing and properties of self-aligned Graphene/Epoxy Nanocomposites

The mechanical, thermal and electrical properties of epoxy/graphene oxide (GO) composites are studied. GO aqueous dispersion is introduced to waterborne epoxy latex and the GO sheets are chemically reduced before curing to produce composites. The epoxy latex particles not only form a continuous matrix but also stabilize the hydrophobic reduced GO (rGO). The chemical reduction improves the mechanical and thermal properties of the nanocomposites by facilitating the interaction between polymer molecules and graphene sheets. The monolayer graphene sheets with a high aspect ratio self-align into a layered structure above a critical concentration thanks to the low viscosity of aqueous dispersion and a long processing time. The aligned graphene nanocomposites display significant anisotropy where the steady-state electrical conductivity along the in-plane direction is three orders of magnitude higher than that of the perpendicular direction. The origins and the practical implications of the self-aligned layered structure of nanocomposites are discussed