On the possibility of the TSD measuring techniques application for PET films thermal endurance estimation

Experiments were conducted on samples of four types of PET (polyethylene terephthalate) film from two different manufacturers. The thermal aging of the PET films was shown to have a complex nature, expressed most markedly during the TSD measurements by changes of the space-charge peak maximum value. This behavior was found for all types of film. The peak change rate can be represented as a linear function of both the aging temperature and the expected time to withstand that thermal stress, estimated on the basis of the IEC 216 standard test. It is not possible at the present stage of study to estimate directly from the TSD measurements an equivalent to the temperature index, despite an existing correlation. Therefore, the method seems to be suitable for accelerated periodic monitoring of PET films whose thermal endurance characteristics are already known