Effect of multi-dimensional zinc oxide on electrical properties of polypropylene nanocomposites for HVDC cables

Polypropylene (PP) is one of the most important high voltage direct current (HVDC) cable insulation materials, which has been widely used in recent years. However, the accumulation of space charge is the most notable problem to limit the practical application of PP. In this paper, the PP nanocomposites filled with polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS) and multi-dimensional zinc oxide composite fillers (co-ZnO) prepared by melt blending method showed excellent properties due to the good compatibility between the co-ZnO filler and PP/SEBS blends. The dielectric permittivity of the composites can be up to 3.1 with 1 wt% doping of co-ZnO. Compared with PP/SEBS, the introduction of co-ZnO filler can largely suppress the space charge accumulation as well as the electric field distortion, and improve the breakdown strength by 14%. It is promising to make the PP/SEBS/co-ZnO composites as one better candidate for HVDC cable insulation materials.