Crystallization Effects on Space Charge Accumulation in Polypropylene under DC Voltage

Polypropylene (PP) is a potential recyclable solid dielectric with promising applications in high voltage engineering. It is known that the crystallization of polypropylene influences its mechanical properties. However, there is no clear correspondence between morphological features and space charge accumulation in PP. In the present work, the polypropylene material was thermally treated at 110°C to recrystallize the sample. Using the principle of the pulse electroacoustic (PEA) method, the effect of re-crystallization on charge accumulation was investigated. It has been found that while re-crystallization occurs, the mesophase and charge traps in PP crystallization increase, leading to the charge migration rate and the total charge accumulation increasing.