Effects of solvent treatment on glass transition characteristics of treated poly(p-phenylene sulphide)

The relationship between solvent-crystallized morphology and glass transition characteristics of poly(p-phenylene sulphide) that had been previously processed with 1-chloronaphthalene is reported. Dielectric relaxation studies revealed a strong positive offset in glass transition temperature (Tg) of the solvent-crystallized samples compared to the corresponding amorphous sample, as well as thermally crystallized samples of similar bulk crystallinity. Additionally, the apparent activation energy for the α-relaxation was higher for the solvent-crystallized case. The dielectric relaxation strength (Δε=ε0−ε∞) determined for the solvent-crystallized PPS is small and showing weak temperature dependence, leading to an increase in Δε as the temperature increased above Tg. This was explained by the existence of a large amount of tightly bound, or rigid-amorphous materials in the solvent-treated sample. We suggested that the large amount of immobile amorphous material, and its ability to relax at temperatures above Tg, is related to strong secondary crystallization process in solvent-treated PPS.