Insulative ethylene-propylene copolymer-nanostructured polypropylene for high-voltage cable insulation applications

Abstract

Worldwide, various efforts to replace crosslinked-polyethylene (XLPE) as an insulation layer in the cable industry, is becoming increasingly popular for improved recycling of polymer waste. Polypropylene (PP) has been proposed as a representative candidate because of its excellent thermomechanical and electrical performances. However, overcoming the mechanical limitations of intrinsic rigidity is required for cable applications. Herein, PP-based insulating materials were prepared via melt-blending with rubbery ethylene-1-octene copolymer (EOC), followed by mixing an ethylene-propylene random copolymer (rPP) as a surfactant for high-voltage power cable applications. Simple melt-blending of rPP formed a core-shell nanostructure composed of EOC/rPP and a fine dispersion of macron-sized EOC domains. The nanostructured PP ternary blends exhibited multiple advantages in terms of thermal stability, mechanical properties, dielectric performances, and long-term stability compared to the existing XLPE. This study provides a straightforward, rational design of environmental insulation materials for high voltage power cable applications.