Electrical breakdown of polyethylene terephthalate under hydrostatic pressure

Measurements of dc dielectric breakdown strength were made on polyethylene terephthalate films of 50 μm in thickness at temperatures of 35, 70, and 100 °C under hydrostatic pressure ranging from 50 to 500 bar. It has been found that the electrical breakdown field Eb increases with pressure and decreases with temperature. It is suggested that thermal breakdown is the dominant process.