High field conduction in heat resistant polymers at elevated temperature for metallized film capacitors

Improved high temperature polymeric dielectrics are in demand for applications such as hybrid electric vehicles, advance aircraft, and deep oil/gas well drilling. Metallized polymeric film capacitors have the advantage of graceful failure as a result of self-healing. As no dielectrics are perfect insulators, trace amount of electrical conduction is always present, especially at high electric field and/or elevated temperature. In this work, high field conductivity and conduction mechanisms of polyphenylene sulfide (PPS) and polyethylene terephthalate (PET) were investigated. Results suggest charge injection through Schottky mechanism and conduction through hopping in both polymers. The average activation energies of PPS and PET were 0.90 and 1.03 eV, respectively.