Space charge behaviors of low-density polyethylene blended with polypropylene copolymer

In this study, the space charge behaviors of the blend polymers of low-density polyethylene (LDPE) and polypropylene copolymer were investigated by the pulsed electro-acoustic method (PEA) with the electrode system of aluminium/specimen/semiconductive layer. The blend specimen composed by 90 wt% LDPE and 10 wt% polypropylene copolymer (B10) showed a larger amount of space charge than pure LDPE (PE) under a DC field of 50 MV m−1 at both 30 and 60 °C. Positive carriers moved more slowly in B10 than in PE under a positive DC voltage applied to the semiconductive electrode at 30 °C. DC currents were also measured under the same experimental condition as the space charge measurement. The DC current of B10 was lower than that of PE at 30 °C, but higher at 60 °C. The experimental results were explained by the introduction of traps by blending.