Impact of cristallinity on the dielectric behavior of polyethylene naphtalate (PEN) by thermally stimulated currents (TSC) experiments

This paper, reported about dielectric characterization of four different structural stat of PEN obtained by heat treatments. The DSC had confirmed that the samples have different crystallinity rate. The use of the thermally stimulated currents technique (TSC) shows a decrease of the maximum intensity of the obtained peaks which represents a net dependence with regard to the crystallinity rate of the material and the crystallization mode. We have observed also a week evolution of fragility index with the crystallinity rate. The real and imaginary parts of the dielectric permittivity at low frequency (f = 10" Hz) have been deduced. A net dependence of the dielectric losses with regard to the crystallinity rate is observed by a net decrease of the imaginary part ε" of the dielectric permittivity when the crystallinity rate increases, Furthermore, The study of the dielectrics behaviors, by the Jonscher equation, shows that the material have a usual dielectrics behaviors, and this behaviors is strongly depending on the method to obtain this cristallinity.