Polyesters dielectric analysis

Dielectric spectra measurements, upon crystallization of PPSu, have been performed by Soccio et al [22], Ciystallization was performed at 25°C. After a controlled period of time the sample was rapidly cooled to -25°C at 5°C/min to perform a frequency swept. PPSu at -25 C that is a temperature above the glass transition temperature exhibits two main relaxations processes characteristic of most polymers, a and in order of increasing frequency. It was foimd that for the polyester the a and relaxations appear simultaneously and are well resolved in the experimental frequency window. The relaxation was used to characterize the ciystalline structural development while the a relaxation was used to collect information about the evolution of the amorphous phase dynamics. In this way structural development could be characterized by a single experiment during the crystallization process. The analysis of the dielectric loss supported the existence of precursors of crystallization in the induction period. 

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