Space Charge and Conduction Character of PP/POE Composites Under High Temperature

The mechanical properties of polypropylene (PP) can be effectively improved by adding elastomers to meet the requirements of cable manufacture. However, the insulation property of PP/elastomer composites will be weakened. The temperature can greatly influence the space charge accumulation in DC condition. And then the electric field distribution and breakdown voltage can be significantly influenced by temperature. This paper studied the electrical properties of PP and elastomer composites at high temperature. The results show that the conduction current densities and the conductivity of the PP and PP/POE composites increase with the temperature rises. The increase at 60 °C is significantly higher than at 40 °C, and the increase of the composites material is much higher than that of PP. The space charge of the PP is stable at high temperature, the amount of space charge accumulation of composites increases with the increase of temperature, and the amount of space charge increases sharply at high temperature. The POE phase begins to soften between 40-60 °C, the molecular chain changes, leading to the decrease of insulation performance at high temperature.