Investigation of the interfacial interactions in epoxy nano-composites filled with functionalized graphene based fillers

This work discusses the investigation of filler-matrix interfacial interactions in epoxy matrices filled with different loadings of graphene based fillers – graphene oxide (GO) and n-butylamine functionalized graphene oxide (GO-ButA). To probe whether the matrix cure reactivity has any influence on these interactions, two different curing agents have been used – a polyetheramine based and an aliphatic amine based to process the nano-composites. Interfacial interactions have been extensively investigated using rheology, DMA and fractographic analysis. As a complementary technique for a better understanding of these interactions, the use of dielectric spectroscopy has been explored. Rheology and dielectric spectroscopy confirm the fillers’ participation in the cure reaction. DMA and fractography show strong interfacial interaction signatures in the slow curing polyetheramine epoxies. The fast curing aliphatic amine epoxies are found to be less amenable in promoting these interactions. However, the filler dispersion quality is observed to be fairly impervious to the curing agent used. Besides surface functionalities of the fillers, the interfacial interactions are seen to be influenced by factors like cure reactivity of epoxy matrices too. Interestingly the thermal stability of the nano-composites is found to be influenced cumulatively by the interfacial interactions and the thermal stability of the fillers.