Curing behavior and physical properties of an epoxy nanocomposite with amine-functionalized graphene nanoplatelets

Amine-functionalized graphene nanoplatelets (AGNPs) were prepared via an easy simple one-step process, treating graphite powder with 4-aminobenzoic acid in polyphosphoric acid, and then the effects of the AGNPs on the curing and physical properties of an epoxy resin were studied. The formation of the AGNPs was confirmed by scanning electronic microscopy (SEM), Fourier transform infrared spectroscopy, and thermogravimetric analyzer. Curing behavior of the epoxy/AGNPs nanocomposite was investigated by differential scanning calorimeter. The AGNPs made the epoxide curing reaction with amine groups slightly faster. The physical properties of the epoxy/AGNPs nanocomposite were investigated by dynamic mechanical analyzer, thermomechanical analyzer, and impact test. The AGNPs improved T_g by 21.4 °C, and storage modulus and impact strength of the epoxy resin 23 and 73%, respectively, much more effective than the graphite powder at the same filler loading of 1 phr. SEM images for the fracture surfaces of the epoxy/AGNPs nanocomposite showed improved interfacial bonding between the epoxy matrix and the nanofillers due to the amine functional groups of the AGNPs.