Effects of nanotitania on structure-dielectric properties of polypropylene blends

Polypropylene (PP) satisfies many of the requirements as power cable insulation thanks to its high thermal stability, ability to withstand high voltages, and eco-friendly properties. Due to the high stiffness and brittleness of PP, the extrusion of PP as power cable insulation becomes difficult. Therefore, elastomers have been blended with PP to enhance PP’s flexibility. Nevertheless, one common issue arises when blending elastomer with PP is the degradation of PP/elastomer blends’ dielectric properties. Recently, nanodielectrics have drawn utmost attention as a promising material system for improving the overall performance of polymer-based insulating materials, but such a material system has yet to be pursued for PP blend materials. The current work therefore investigates the effects of titania (TiO 2 ) on the structure and dielectric properties of PP/ethylene-based elastomer (EBE) and PP/propylene-based elastomer (PBE). While adding high amounts of TiO 2 degrades the blend materials’ breakdown strength, the inclusion of small amounts (0.5 wt% and 1 wt%) of TiO 2 improves the breakdown strength of the blend materials by as much as 10%. Notably, the effect of TiO 2 is more apparent on PP/EBE system over PP/PBE system. Mechanisms underlying changes in the breakdown strength of the materials, under both alternating current (AC) and direct current (DC) fields, are analyzed.