TSD-study of polyethylene photochemical degradation

Thermally stimulated depolarization of PE films subjected to photochemical aging was carried out. Thermally stimulated current spectra were obtained and interpreted in terms of the classical dielectric model with discrete trapping levels. Maximums on the temperature plots of thermally stimulated currents were explained by detrapping of charge carriers through two types of competitive photoinduced processes: weakening of the intermolecular interaction responsible for relaxation processes and structuring, on the one hand, and displacement and concentration of dislocations, the appearance of microcracks, and the transformation of supermolecular entities by crosslinking of macromolecules, on the other hand. Thermally stimulated current spectra bear information on the technological history of the films. The technique of thermally stimulated depolarization is useful to obtain new information on the photochemical aging of polymers.