Competitive relationship between electrical degradation and healing in self‐healing dielectric polymers

Abstract

The concept of self‐healing dielectric polymers has been heatedly discussed, with the expectation of high damage resistance and longer service time. However, there is still a lack of analysis on the competitive relationship between electrical degradation and self‐healing. The authors discussed this relationship in two stages: the design of self‐healing strategies and the operation of self‐healing polymers. Since the requirements for excellent insulating or mechanical properties are not consistent with the demands for high self‐healing capability, trade‐offs are necessary during the design of self‐healing polymeric systems. In the operation stage of dielectric polymers, some key factors that affect the service lifetime of non‐autonomous self‐healing dielectric polymers are analysed, including the efficiency and repeatability of self‐healing, and the frequency of healing maintenance. For autonomous self‐healing dielectrics, the simultaneous processes of ageing and healing are investigated using a self‐healing epoxy resin based on microcapsules and in situ‐generated radicals. A quicker recovery of insulating properties, in terms of partial discharge magnitude, was observed under appropriate healing voltages. However, the self‐healing ability might vanish when the voltage was too high, verifying the competitive relationship between electrical degradation and self‐healing.