Design, preparation, and characterization of fast cure epoxy/amine‐functionalized graphene oxide nanocomposites

Fast cure epoxy/amine‐functionalized graphene oxide (GO) nanocomposites were designed, prepared, and characterized in this work. The GO nanosheets were functionalized by aliphatic amines having the same structure but different chain length. XPS and FTIR analyses were used to probe chemical structure and elemental surface composition of nanosheets before and after functionalization. Cure kinetics analysis was performed by dynamic differential scanning calorimetry (DSC) on samples containing pristine and functionalized GO to achieve minimum possible hindered cure. Kinetic studies confirmed that addition of pristine GO brings a steric hindrance effect, as signaled by a fall in the onset temperature, exotherm temperature and the total heat of curing reaction. According to isoconversional model, activation energy of cure reaction fell from approximately 80 to slightly over 60 kJ mol−1 as a result of improved dispersion. SEM micrographs provided evidence for good dispersion of GO platelets bearing short‐arm amines; but activation energy in such system was surprisingly higher than that of the one filled with pristine GO. By contrast, network formation in nanocomposites with GO functionalized by long‐arm amine has been facilitated, signifying the dominance of aliphatic amine length over dispersion state. The accelerated/decelerated cure is inferred based on the reactivity of reaction moieties, dispersion state of GO in the epoxy matrix, and cure behavior/kinetics of nanocomposites. The developed fast cure epoxy/GO nanocomposites compete in crosslinking with blank epoxy system. POLYM. COMPOS., 39:E2016–E2027, 2018. © 2017 Society of Plastics Engineers