Synthesis and Characterization of Carboxyl-terminated Hyperbranched Polyester

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 degrees 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.