Reinforcement of Epoxy Resin by Additives of Amine-Functionalized Graphene Nanosheets

In this study, graphene oxide (GO) nanosheets were modified with an amine functional group to obtain amine-functionalized graphene (AMG) nanosheets and then blended with the aniline curing agent of bisphenol-A (BPA) epoxy resin to crosslink BPA epoxy resin. The AMG-blended curing agent and BPA epoxy resin formed an intermolecular hydrogen bond that was stronger than the π–π stacking force between benzene rings of graphene nanosheets. Therefore, AMG nanosheets exhibited excellent dispersion in the aniline curing agent. The amine group of AMG-blended curing agents and the epoxy functional group of BPA epoxy resin exhibited strong chemical activity and underwent crosslinking and polymerization. AMG nanosheets were mixed with BPA epoxy resin to form a crosslinked structure through the epoxy ring-opening polymerization of the resin. The mechanical properties of the epoxy resin nanocomposites were significantly improved by the added 1 wt.% AMG nanosheets. The tensile strength was enhanced by 98.1% by adding 1 wt.% AMG in epoxy. Furthermore, the impact resistance of the epoxy resin was enhanced by 124.4% after adding 2.67 wt.% of AMG nanosheets. Compared with other reinforced fillers, AMG nanosheets are very light and can therefore be used as nanocomposite materials in coating applications, the automotive industry, aerospace sheet materials, wind power generation, and other fields.