Space charge and conduction in LDPE-polypropylene copolymer blends

In the previous paper, the electrical breakdown properties of blend polymer of LDPE and polypropylene copolymer were investigated. The impulse breakdown strength in the high temperature region (90 degreesC) was improved by blending. In the present paper, the space charge behavior and electrical conduction of the blends were studied with the electrode system of aluminium/sample/semiconductive layer. The specimen with 90 wt% LDPE and 10 wt% polypropylene copolymer (B10) had a larger amount of space charge than pure LDPE (PE) at 30 degreesC. On the other hand, the DC current of B10 was less than that of PE in this temperature region. It was found that the anode field was related to the current in both PE and B10, which suggests that the carrier injection from the anode is dominant to the electrical conduction. The DC currents of both PE and B10 showed good straight lines on the Schottky plot with the same Schottky coefficients.