Process parameters optimization to disperse graphene nanoplatelets into epoxy polymer to improve electrical conductivity

Polymer composites have exceptional advantage over traditional materials. A primary limitation of fiber reinforced polymeric composite in aircraft applications is susceptibility to lightning strike because of poor electrical, thermal and electromagnetic properties. The current methods to mitigate the lightning strike in aircraft have added weight and reduced the performance. As a first step in this direction graphene modified epoxy nanocomposites was being developed using a scalable dispersion technique to improve electrical conductivity. Three different types of dispersion techniques were investigated in this study: mechanical mixing, sonication, and three-roll mill dispersion. The study showed that three-roll mill dispersion is most repeatable, consistent, and scalable to larger batches. In the case of three-roll mill dispersion technique, the percolation threshold was found to be 1.0 wt % of graphene. Electrical conductivity of epoxy increased around 8 log cycles over the unmodified epoxy resin.