Tuning the interface of graphene platelets/epoxy composites by the covalent grafting of polybenzimidazole

This paper reported a facile one-pot strategy for covalent functionalization of graphene platelets (GnPs) by polybenzimidazole, and the fabrication of their composites with epoxy resin. The functionalized GnPs (fGnPs) was prepared by subsequently acylation reaction between dicarboxylic acid and GnPs, and in-situ polymerization of polybenzimidazole. Spectroscopic studies and elemental analysis confirmed the successful grafting of polymer chains and the highly integrated structure of fGnPs, while TEM images demonstrated the well exfoliated state of fGnPs in organic solvent. As a consequence of the good dispersion state of fGnPs in matrix, and the covalent interactions between fGnPs and epoxy, the fGnPs/Epoxy composites showed significantly improved Young's modulus, tensile strength and fracture toughness as compared to neat epoxy or unmodified GnPs reinforced epoxy. The improved dynamic mechanical properties and thermal stabilities of composites filled with fGnPs were also demonstrated.