Lifetime characteristics of electrically and thermally preagedpolypropylene films

摘要

Constant stress voltage aging studies were conducted onelectrically and thermally preaged 25-μm-thick capacitor-gradepolypropylene (PP) films, and lifetime characteristics were determinedat room temperature. The electrical preaging level was 70% of thebreakdown voltage applied for one and two hour durations. For thermalpreaging, the film was heated at 90° C for five hours and ten hours,respectively. It is noted that both modes of prestressing seem to affectthe lower end of the test field region, where nonlinear failuremechanisms predominate. The results are presented and analyzed on thebasis of available theoretical aging models, and possible newinterpretations are discussed. A thermodynamically favorable breakdown,is indicated for electrically preaged data, while no such consistentrelation was obtained for the thermally preaged data