Dielectric studies of poly(vinyl chloride)

Measurements of the dielectric constant and loss factor of polyvinyl chloride (PVC) have been made over a wide range of temperature and frequency. Maxima in dielectric loss were observed at a temperature corresponding to the α or glass transition temperature and secondary β transition temperature. The sensitivity of these maxima to both frequency and thermal pretreatment was investigated. It was found that the position of the β peak on the temperature axis changed markedly with frequency, while the glass transition or α peak showed only small variations. Neither the α nor the β peak were very sensitive to thermal pretreatment, but interesting changes in the minimum between these peaks were observed. In quenched samples a distinct shoulder peak at T β < T s < T α was observed; it was possible to eliminate it by a slow cooling of the samples. The effect of plasticizer content was also studied.