Experimental study on property of space charge for polyethylene doped with nano-powder

In this study, packet-like space charge behavior in linear low-density polyethylene (LLDPE) and LLDPE doped with two different nano-powder (Al₂O₃, MgO) were investigated by the pressure wave propagation (PWP). This paper focuses on the space charge dynamics and the isothermal decay process in LLDPE doped with Al₂O₃ and MgO by sligt concentration (0.01 wt%, 0.05 wt%, 0.1 wt%, 0.2 wt%, 0.5 wt%, 1 wt%). The 1 mm sheet samples, sandwiched by semi-conductive electrodes, were submitted to DC high voltage of 40 kV/mm for 3 hours at 40degC. The results show that, Al₂O₃/LLDPE with doping concentration more than 0.2 wt% can be effective to suppress the charge injection. For MgO/LLDPE sample, the value is 0.5 wt%.