Influence of temperature-history on the AC breakdown of isotactic polypropylene

Isotactic polypropylene is rapidly becoming the dielectric material of choice in most of the high voltage and pulsed power capacitor applications. Polymers lend themselves to a variety of heat treatments resulting in samples possessing a wide range of crystal 1 inities and morphologies. There have not been many studies dealing with the effect of temperature history on the breakdown characteristics of polymers. Most of the existing studies have dealt with the effect of temperature history on the DC or impulse strength of polyethylene [1–3].