Investigation of charge transport and breakdown properties in XLPE/GO nanocomposites part 1: The role of functionalized GO quantum wells

The charge transport characteristics and breakdown properties of cross-linked polyethylene (XLPE)/graphene oxide (GO) nanocomposites are investigated in this study. The functionalized graphene oxide (fGO) quantum wells (QWs) with quantum confinement effects were produced by chemically grafting the polycyclic aromatic compounds (PAC) onto the surface of GO QWs. The XLPE/GO nanocomposites doped with different kinds of dopants were prepared by mechanical blending, of which the DC conductivity, space charge behaviors, and breakdown strength were measured. The experimental results reveal that the GO QWs show a synergistic effect with PAC on the modification of insulating properties in XLPEs. The grafted PAC on the surface of GO QWs still retains its original function of attenuating the energy of charge carriers, while the interlayer distances of fGO QWs increase after functionalization. As a result, the XLPE/fGO nanocomposites show a much lower conductivity, fewer space charge accumulation, and higher breakdown strength than those of the other XLPEs. Based on the quantum chemistry calculation method, the role of fGO QWs in the regulation of charge transport and breakdown properties in polyethylene was revealed.