Thermal and crystallization behavior of engineering polyblends. II. Unfilled polyphenylene sulfide with poly (ethylene terephthalate)

The melting and crystallization behavior of blends of poly(phenylene sulfide) (PPS) with poly(ethylene terephthalate) (PET) has been investigated. The component polymers in the blend exhibited separate crystallization peaks and overlapping melting peaks. The nonisothermal DSC scans indicated that the crystallization parameters for PET become modified to a greater extent than do those for PPS in the blends. The PET crystallization peak became narrower with a higher heat of crystallization, suggesting a faster rate of crystallization as a result of blending with PPS. The isothermal crystallization studies revealed that the nucleation of PPS is facilitated by the presence of PET. This contention has been substantiated by polarized light microscopic observations. The spherulites of PPS were found to be smaller in the blends as compared to those in neat PPS. This enhancement in the nucleation of PPS has been attributed to the possibilities of chemical interactions between the component polymers. On the other hand, the increase in the rate of crystallization of PET has been attributed to the heterogeneous nucleation provided by the alreadycrystallized PPS. The melt crystallized blends exhibited slightly higher heats of fusion compared to the values computed from the rule of proportional additivity