Simulation of charge transport in polypropylene-based nano-composites

Abstract

Polypropylene (PP)-based polymers are environmentally friendly and degradable materials that make them attractive alternatives to polyethylene for the electrical insulation systems of power cables in the future. To enhance the insulation performance of PP and to impede leakage currents through the material, different admixtures are utilized. In this paper, the effect of nano-fillers on charge transport characteristics in PP composites under DC electric fields is investigated by using a bipolar charge transport model accounting for mobile and trapped electrons and holes as well as ionic species. The model was validated by comparing the numerical results with the experimental data. The dynamic distributions of space charge densities and electric field in PP with and without nano-fillers are analyzed and compared. The numerical results confirmed that 0.5 phr ZnO nano-fillers can significantly improve the electric field distribution in PP nanocomposites and suppress the bulk current by reducing the charge generation rate and mobilities of charge carriers, thus resulting in a decrease in the volume conductivity. The obtained results provide a theoretical background for tailoring PP-based composites for specific applications by controlling nano-fillers.