Chemically modified graphene oxide/polybenzimidazobenzophenanthroline nanocomposites with improved electrical conductivity

Graphene/polybenzimidazobenzophenanthroline nanocomposites were prepared through the liquid-phase exfoliation of graphene oxide (GO) and reduced graphene oxide (rGO) in methanesulfonic acid with subsequent solution mixing. Various chemical and combined chemical-thermal methods were examined to be effective for producing rGO with highly graphitic structure and excellent electrical conductivity. Raman and X-ray photoelectron spectroscopy showed higher degree of reduction of the GO with the combined chemical-thermal method compared to other chemical reduction processes. Structural characterization of the nanocomposites by X-ray diffraction, scanning electron microscopy and transmission electron microscopy showed good exfoliation and dispersion of both GO and rGO fillers in the polymer matrix. The thermogravimetric analysis found that the nanocomposites with rGO have higher onset and maximum weight loss temperatures than those with GO. Compared with the pure polymer, the electrical conductivity of the nanocomposites containing 10 wt% GO and GO reduced by the combined chemical-thermal treatment showed a remarkable increase by four and seven orders of magnitude, respectively. Long-term in-situ thermal reduction was performed to further improve the conductivities of the nanocomposites.