Effect of PTW on crystallization kinetics of toughened PBT/PC blends

Abstract

Poly(butylenes terephthalate) (PBT)/polycarbonate (PC)/poly(ethylene- butylacrylate-glycidyl methacrylate copolymer) (PTW) blends containing PTW as toughening modifier were obtained by extrusion and injection molding. The effect of PTW on the melt rheology of PBT/PC blend was examined by means of capillary calorimetry. The rheological properties of the blends suggested high reactivity between epoxy groups in PTW and terminal carboxylic acid group and/or hydroxyl group of PBT inhibited transesterification between PBT and PC. The effect of PTW on the crystallization of PBT in the PBT/PC/PTW blends was investigated by crystallization kinetics analysis under isothermal and nonisothermal conditions. Isothermal crystallization experiments were performed at crystallization temperature and analyzed based on the Avrami equation. A decrease of the half time of PBT crystallization t1/2, as well as an increase of the overall crystallization rate of PBT in the PBT/PC/PTW blends have been observed. Nonisothermal crystallization experiments were performed at given cooling rate. The Ozawa analysis is used to describe its nonisothermal crystallization behavior. It is observed that at a given cooling rate, the PTW increases the overall crystallization rate of PBT in the PBT/PC/PTW blends. This is consistent with the result obtained under isothermal crystallization condition.