Polypropylene-based soft ternary blends for power cable insulation at low-to-high temperature

Although cross-linked polyethylene (XLPE) has been widely used as a power cable insulation material in electricity infrastructure for decades, it is necessary to find alternatives that exhibit higher performance than XLPE to meet the increasing demand of the industry. To this end, polypropylene (PP) ternary blends that are soft and exhibit high temperature stability were fabricated by melt blending isotactic PP, ethylene-1-octene polyolefin elastomer and ethylene-propylene random copolymer. These blends exhibited improved higher impact resistance at low temperatures (-40 degrees C) and room temperature than pristine iPP. The blends were mechanically stable even when the temperature was increased to similar to 120 degrees C, unlike XLPE that exhibited rapid degradation of its modulus above similar to 90 degrees C. Moreover, the soft ternary blends exhibited increased direct current volume resistivity and breakdown strength. Our work realizes the development of high-performance insulators for power cables that can be used over a wide range of temperatures from cold to hot environments.