Abstract: Acrylonitrilestyreneacrylates terpolymer(ASA) was employed to toughen polybutylene terephthalate (PBT). Scanning electron microscope (SEM) and dynamic rheometer were used to investigate the phase morphology and rheological property of PBT/ASA blends. It was clear that ASA could effectively improve the melt strength of PBT, and the PBT/ASA blend was a partly compatible system with compositon dependence. The microphase of the blends showed a typical “seaisland” structure at low ASA content, and a phase inversion occurred in an ASA content range of 40 wt %～60 wt%.

Key words: polybutylene terephthalate, acrylonitrilestyreneacrylates terpolymer, phase morphology, rheological property, phase inversion