Effect of graphene filler structure on electrical, thermal, mechanical, and fire retardant properties of epoxy-graphene nanocomposites-a review

The use of graphene materials, i.e. graphene oxide, reduced graphene oxide, graphene nanoplatelets and their functionalized forms as fillers of epoxy composites, is reviewed. The purpose of the time- and reagent consuming functionalization methods of graphene materials is justified by the noticeable improvement of dispersity and adhesion of the graphene sheets to the epoxy matrix, which affects the final properties of graphene-epoxy composites. The state-of-the-art of multifunctional graphene-epoxy composites developed over the last years is critically reviewed. The influence of the graphene filler structure and dispersion preparing procedure on the morphology of epoxy-graphene composites and, consequently, their electrical and thermal conductivities, mechanical strength and flame retardant characteristics is considered. An evolution from epoxy-graphite microcomposites to epoxy-graphene nanocomposites is presented, showing the benefits of graphene materials for composites. Some recent works on the epoxy composites reinforced with hybrid graphene fillers and combinations of graphene materials with other fillers are described.