TSDC study of electrical aging of polybutylene terephthalate (PBT)

Aging may introduce one or more modifications in a polymer when it is submitted to certain stresses. In this work, we have investigated in particular electrical aging of polybutylene terephthalate (PBT) by the thermally stimulated depolarization current (TSDC) method. This study consists in subjecting a sample to different electric fields Ea, with intensities lower than the breakdown field of the material during different times Ata. The results reveal a decrease in the polarization of the material which is probably caused by an injection of space charges. This effect induces a decrease in the activation energy, fragility index and dielectric loss factor. Also, the compensation parameters are affected by this aging.