Evaluation of fatigue property of PET tyre cord and rubber by using thermoluminescence

Glow curves have been measured at different heating rates for samples of polyethylene terephthalate (PET) tyre cords and tyre rubber before and after fatigue. From these measurements values of the thermoluminescence activation energy (E) and frequency factor (S) have been derived. E and, most strikingly, S, both increased during fatigue. It is suggested that the changes observed in E and S offer a new approach to the study of fatigue resistance in organic polymers. (U.K.)