Space charge and breakdown strength behaviour of PP/POE/MgO nanocomposites

Polypropylene (PP) is considered a competitive candidate to replace widely used cross-linked polyethene (XLPE) in cable material application, as it can potentially withstand higher operating temperature and has excellent electrical properties. Besides, it is a more environment-friendly material, since PP does not require crosslinking and, therefore, can be easily recycled at the end of its life. This paper investigated the influence on the tensile strength, space charge and breakdown behaviours of the PP by adding polyolefin elastomer (POE) and Magnesium Oxide (MgO) nanoparticles. 10 or 20 wt. % of POE and 5 or 10 wt. % of nano-MgO were introduced into PP. Results show that the PP with 10 wt. % of PE02 and 5 wt. % of surface treated-MgO has the highest breakdown strength among all systems. Also, the introduction of POE and nano-MgO can significantly improve the mechanical flexibility. In combination with the observed suppression of space charge accumulation, which shows that PP/POE/MgO nanocomposites are a viable option for high voltage (HV) cable insulation material in the future