Accelerated life studies of polyimide film under electrical andthermal multistress

摘要

Accelerated life studies on a high-temperature polyimide film(Kapton) were conducted under simultaneous electrical and thermal stressat 60 Hz and 400 Hz. The breakdown strength and the agingcharacteristics were obtained at test temperatures of 23° C,100° C and 200° C. The two-parameter Weibull distribution was usedin the evaluation of the experimental data. The experimental resultsshow that electrical aging, by increasing the applied voltage or theapplied frequency, is the mechanism responsible for failure under theseconditions, and that thermal aging is not a major degradation factor forthe Kapton film in the applied temperature range, particularly at thehigher frequency of 400 Hz. Several theoretical models were consideredto obtain the best approximation to the experimental data. The analysisshows that present physical models cannot take into account accelerationof aging with the applied frequency