Electrical discharge resistance of polymeric nanocomposites

The trend of choosing insulating materials has changed in the past few decades, and a considerable shift has occurred from conventional ceramic to non-ceramic insulating materials. The addition of inorganic fillers has greatly improved the thermal conductivity, discharge resistance, hydrophobicity recovery, and vandalism-resistance properties of polymeric insulating materials. Since the beginning of the present century, the field of nanomaterial research has gained much attention. Several studies have been conducted to investigate and analyze polymer nanocomposites by adding nanoparticles of varying size and concentration as fillers. The aim is to improve the characteristics and reformation of thermal, electrical, and mechanical properties of existing polymeric insulation materials. However, certain inconsistencies are prevalent with results obtained for polymer nanocomposites. A comprehensive review is presented based on available literature focussing on the advancement from polymeric insulating materials to polymeric nanocomposites and its impact on partial discharge resistance, surface charging, and tracking and erosion resistance. It is observed that the weight percent and dispersion of nano- or micro-sized particles into the base polymer matrix governs the performance of polymer composites. At higher filler loading, resistance to partial discharge and tracking and erosion decreases as a result of the agglomeration of fillers, whereas resistance to surface charge accumulation increases at higher filler loading because the formation of shallow traps increases the charge decay rate. It is suggested that when both micro- and nanofillers are mixed in proper proportion, micro–nano hybrid composites provide better performance than composites filled with only nano- or microfillers.