Electrothermal lifetime prediction of polyimide wire insulation with application to aircraft

This work investigates the electrothermal lifetime of a commonly used polyimide wire insulation material, Kapton ® , through the use of thermogravimetry (TG) and breakdown voltage testing. From TG, an isoconversional model‐free kinetic evaluation was used to obtain a relationship between the activation energies of degradation for Kapton as a function of weight loss. By relating the electrical life theory and the TG theory through the model defined by Toop ( IEEE Trans. Dielectr. Electr. Insul . 1971, 6, 2), the electrothermal lifetime of Kapton has been calculated for conditions of 12 and 14.7 kV over a temperature range of 250–400°C. The resulting model can be used to make lifetime predictions for wire insulation degradation in aging aircraft for improved safety and risk assessment. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1639–1644, 2013