CRYSTALLIZATION BEHAVIOR OF POLYPHENYLENE SULFIDE IN BLENDS WITH A LIQUID-CRYSTALLINE POLYMER

Blends of polyphenylene sulfide (PPS) with a commercial, wholly aromatic, liquid crystal copolyesteramide (Vectra-B950) have been prepared by melt-blending. The crystallization behavior of neat and blended PPS has been studied by differential scanning calorimetry (DSC), under both non-isothermal and isothermal conditions. It has been found that blending PPS with Vectra-B leads to an increase of the temperature of non-isothermal crystallization and to a pronounced acceleration of the isothermal crystallization, without any reduction of the degree of crystallinity. All these effects have been found to occur independent of the Vectra-B concentration, within the investigated range (2 to 20%, w/w). The results have been interpreted in terms of an increased nucleation density of the blends, probably due to heterogeneous substances, initially present in the Vectra-B bulk, which dissolve to saturation in the PPS phase, during melt-blending.