Poly (trimethylene terephthalate)/acrylonitrile-styrene-acrylic copolymer blends were prepared and their morphology, thermal aging and mechanical properties were investigated by using the polarized optical microscopy, universal material testing machine and color-difference meter, repectively. The results suggest that ASA and PTT are partially miscible in the blends, and when TPEE content is 50%, a bi-continuous phases form in the blend. The PTT’s spherulites in the blends become smaller and even microcrystallites with increasing ASA content. ASA component has good effect on toughen PTT by increasing blends’ impact strength but depresses the tensile strength of the blends. ASA has no influence on the thermal aging properties of PTT, and PTT/ASA blend has better thermal aging resistance than that of PTT/ABS blend.

In order to prepare carboxyl-terminated hyperbranched polyester (HBP-COOH), succinic anhydride was used to modify hydroxyl-terminated hyperbranched polyester (HBP-OH), and the influences of the solvents, catalysts and time on the product’s structure were investigated. When THF is used as the solvent, sodium acetate as the catalyst, the molar ratio of succinic anhydride and hydroxyl groups is 3:1, and the reaction time is 6 h at 65°C, the modification extent of the hydroxyl groups is about 99% with about 95% yield. HBP-COOH has much lower glass transition temperature than that of HBP-OH due to its long and flexible end-groups.