Enhanced Thermal and Mechanical Performance of Functionalized Graphene Epoxy Nanocomposites: Effect of Processing Conditions, Different Grades and Loading of Graphene

Graphene nanoplatelets (GnPs) belong to a category of recently innovated inexpensive materials that comprises of a small pile of graphite layers that has often been employed to augment the tensile strength of composites. In this work, acid modified Polyacroyl chloride (PACl)-functionalized GnP has been incorporated in epoxy (Epon 828) matrix and the effect of solution processing on the thermal, viscoelastic and mechanical properties of the nanocomposites was investigated. As a result of the acid treatment, hydroxl groups were incorporated on to the GnP backbone which in turn served as a site for covalent bonding with the acyl chloride groups of PACl. The unreacted acyl chloride groups bonded to the epoxy in the nanocomposite. The nanocomposites were prepared in the presence of acetone as a solvent (solvent processed) and also in the absence of solvent. The fractured surfaces of the prepared nanocomposites upon tensile testing were examined using scanning electron microscopy (SEM) which revealed the strong interfacial bonding between the functionalized GnPs and epoxy matrix. The thermal and viscoelastic properties of the nanocomposites were characterized by thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA), respectively. It could be concluded that the mechanical and thermal properties of epoxy nanocomposites were improved to an appreciable extent upon the incorporation of functionalized GnPs and the processing conditions played a pivotal role in controlling the aforementioned properties.