Effect of nanoparticle surface modification on charge transport characteristics in XLPE/SiO2 nanocomposites

This paper focuses on the effect of nanoparticle surface modification on the charge transport characteristics in XLPE/SiO₂ nanocomposites. A titanate coupling agent (TC9) and a 3- (Methacryloyloxy)propyltrimethoxysilane (KH570) were used for the surface modification of SiO₂ nanoparticles. It was found that both KH570 and TC9 coupling agents improve the nanoparticle dispersion compared with unmodified SiO₂ nanoparticles. The improvement in dispersion was found to be due to increased surface hydrophobicity of the treated SiO₂ nanoparticles. In addition, it was found that the surface modification improved the DC conductivity, dielectric characteristics, and space charge properties as compared to XLPE or XLPE/SiO₂ nanocomposites without surface modification. The results of the TSC measurements showed that the introduction of SiO₂ nanoparticles into XLPE increased the trap density and produced more trap energy levels. Improving the nanoparticle dispersion was found to further increase the corresponding trap depth and trap density. The trapped homocharge formed an independent electric field and reduced the effective electric field, which reduced charge injection and increased the charge injection barrier height. Therefore, the space charge formation in the material bulk was suppressed.