Grafting polycarbonate onto graphene nanosheets: Synthesis and characterization of high performance polycarbonate-graphene nanocomposites for ESD/EMI applications

Abstract

We have developed high performance polycarbonate-graphene nanocomposites with outstanding mechanical and electrical properties by grafting polycarbonate (PC) onto graphene nanosheets (PC-g-MGNS). The PC-g-MGNS nanocomposites were synthesized by grafting hydroxyl-terminated PC onto methylene diphenyl diisocyanate-functionalized graphene nanosheets (MGNS); the MGNS were synthesized via the alcoholysis reaction between 4,4′-methylene diphenyl diisocyanate (MDI) and chemically reduced graphene nanosheets (GNS). The resulting PC-g-MGNS nanocomposites exhibit dispersions of graphene in the PC matrix that are much better than those of PC-graphene nanocomposites prepared via simple mixing in a solvent (s-PC/GNS) and provide highly enhanced mechanical strength and electrical conductivity. For instance, the PC-g-MGNS nanocomposite containing 3.0 wt% graphene exhibits an ∼20% increase in tensile strength, an ∼23% increase in Young's modulus, and three orders of magnitude greater electrical conductivity when compared with the equivalent s-PC/GNS nanocomposite.