Crystallization, thermal behavior and Compatibility in isotactic Polystyrene/Poly(o-chlorostyrene-co-p-chlorostyrene)

The dependence of the kinetics of crystallization and melting behavior in isotactic polystyrene/ poly-o-chlorostyrene-co-p-chlorostyrene (iPS/P(o-ClS-co-p-ClS) blends on temperature, thermal history, and blend composition has been investigated. The crystallization rate at a given temperature and copolymer composition decreases with increasing copolymer content in the blend when the samples are premelted. These effects can be ascribed to the reduction of mobility of the crystallizable chains due to the presence of the copolymer and to the decrease in the number of heterogeneous iPS nuclei as a result of the premelting process. The Avrami exponent values and the analysis of the blend morphology indicate that the growth mechanism of the crystals is strongly influenced by thermal treatment. From the comparison of the phase diagram for the isotactic polystyrene-containing blend with that of the atactic-containing blend, it can be concluded that in the amorphous state polystyrene with a regular configuration is slightly less compatible with the P(o-ClS-co-p-ClS) than is polystyrene with random configuration.