Enhancing Epoxy Composites with Graphene and Graphene Oxide: Thermal and Mechanical Insights

Abstract

This paper shows the graphene and graphene oxide nanoflakes as the 0.1, 0.5, 1, 2, and 4 wt.% reinforcement of epoxy-resin matrix to enhance the thermal and mechanical characteristics of the composite. Experimental measurement of the glass transition temperature and thermal expansion coefficient indicated that the addition of nanostructural filler improving the glass transition temperature about ~12 °C for nanocomposite filled carbon-based nanoparticles for both heating and cooling cycles compared to the bare epoxy resin. Young's elastic modulus measured by nanoindentation and the stress versus strain curves for different weight fractions of graphene nanoflakes additives during uniaxial compression and tension considered were obtained from the experiments. The distributions of logarithmic strain field for the transverse, axial and shear components on the nanocomposites sample surfaces, during the uniaxial tension process for quasi-static strain rates, were analyzed. The tensile strengths show improvement for nanocomposites with less than 1 % weight fraction of carbon-based nanoparticles. The compressive yield stress increased to a maximal value (at the recorded peak on the curve) for an epoxy nanocomposite having 2 wt.% oxidized graphene flakes, where both parameters were enhanced with the oxidized form of graphene for the more effective dispersion in the epoxy resin matrix over the bare graphene filler.