NONISOTHERMAL CRYSTALLIZATION KINETICS OF POLY(PHENYLENE SULFIDE) VECTRA-B BLENDS

The non-isothermal crystallization behaviour of blends of poly(phenylene sulfide) (PPS) with the thermotropic liquid-crystalline copoly(ester amide) Vectra-B950 (VB) was studied by means of differential scanning calorimetry. The PPS crystallization temperature and the crystallization rate coefficient were found to increase markedly upon addition of 2-50% VB. It was shown that the Ozawa equation is valid not only for neat PPS but also for the blends. The values of the Avrami exponents are in fair agreement with those found previously by isothermal analysis, and do not depend on the presence and the concentration of VB. It has been suggested that the slope of the plots of the cooling crystallization function versus T can be a criterion for the overall non-isothermal crystallization rate. It has been concluded that the non-isothermal crystallization of PPS is strongly accelerated by the presence of the VB phase, whereas the type of nucleation and the geometry of crystal growth do not change, and no reduction of the PPS degree of crystallinity could be noticed.