Effect of Elastomer Content on AC Breakdown Performance of PP Blends

Recently, many studies have been conducted on various dielectric materials, especially polymer/elastomer blends, with the aim of examining the materials’ potential improvements in high voltage insulation. In particular, the interaction between the polymer and the elastomer acts an imperative role in the dielectric properties of the materials. Polypropylene (PP) has been blended with elastomers to improve their electrical and mechanical properties. In spite of this, adding elastomers to PP may negatively affect its electrical properties, making it a major challenge for PP modification. In this paper, a study on the morphology and AC breakdown performance of crosslinked polyethylene (XLPE), PP, and PP blends containing 10, 30, and 50 wt% of ethylene-octene copolymers (EOC) has been conducted. The morphological image results indicate uniform dispersion of EOC into the PP matrix. Although PP itself has the highest AC breakdown strength (169 kV/mm), adding up to 30 wt% of EOC to PP results in AC breakdown strength commensurate with that of XLPE (145 kV/mm). This indicates the promising use of the PP/EOC blend in replacing XLPE with respect to morphological and AC breakdown properties.