Influence of thermal and UV aging on electroluminescence of polypropylene films

Polymer aging appears to be an important factor which affects the electroluminescence of polyolefins subjected to a homogeneous AC field. We investigate the influence on electroluminescence emission of thermal and UV aging of commercial polypropylene films for capacitor application. Chemical and morphological changes of the materials are studied as function of aging conditions. Correlation is found between material oxidation and electroluminescence. Oxidation reduces the level of electroluminescence but does not change the spectral distribution of the light, thereby indicating that the luminescence centers are not the carbonyl groups.