Effect of elastomer type on electrical and mechanical properties of polypropylene/elastomer blends

摘要

Thermal plastic material polypropylene (PP) has been considered as a promising candidate for recyclable insulation of power cable. However, the stiffness of PP is higher than that of XLPE which makes it difficult to be used directly as cable insulation. In this work, two kinds of elastomers, i.e. polyolefin elastomer (POE) and propylene-based elastomer (PBE), have been added into isotactic polypropylene (i-PP) to modify its toughness. Effect of the elastomer type on electrical and mechanical properties of the blends has been estimated. It was found that with the increase of the elastomer content from 0wt% to 30wt%, the trap depth appeared to be shallower, and the carrier mobility tended to increase. As compared with the PP/POE blends, the PP/PBE blends showed deeper trap which may be responsible for its higher DC breakdown strength. In addition, with the growth of the elastomer content, the elongation at break was enhanced for both the two blends. The PP/PBE blends had higher elongation at break than PP/POE blends. It is suggested that the better electrical properties of PP/PBE should be attributed to its good compatibility with the base i-PP.