DIELECTRIC RELAXATIONS IN POLY[2,2-PROPANE-BIS-(4-PHENYL THIOCARBONATE)]
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Date
1992
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Abstract
The dielectric relaxation properties of poly[2,2-propane-bis-(4-phenyl thiocarbonate)] (PTC) have been studied. The existence of crystallinity, which can be eliminated by quenching, is detected. The degree of crystallinity of polymer samples was determined by differential scanning calorimetry in order to investigate the effect of this factor on the dielectric behaviour of this polymer. The thermal degradation of the samples was studied by thermogravimetry. The degradation of the polymer begins before the glass transition temperature T(g). The dielectric spectrum is complex showing several relaxation phenomena. With increasing temperature a gamma-relaxation can be observed at - 100-degrees-C (5 kHz). The activation energy obtained from an Arrhenius plot (ln f vs T-1) is 6 kcal mol-1. At 160-degrees-C the alpha-relaxation which is associated with the glass transition temperature T(g) is detected. The dielectric behaviour of this poly(thiocarbonate) is compared with the corresponding poly(carbonate).
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RELAXATIONS, ACTIVATION ENERGY, MOLECULAR MOTIONS, DIELECTRIC SPECTRUM