Abstract: A rosin based hyperbranched polyester(HBP) was prepared by copolycondensation of maleopimaric acid(MPA), trimethylolpropane(TMP), and glycerin. When the mole ratio of alcohol to acid was 3:1, the effects of reaction temperature, material ratios, and catalyst contents on the hyperbranched polyester synthesis were discussed. The results showed that the optimal conditions were as follows: the mole ratio of glycerin to TMP 1:1, the dosage of catalyst 0.2%, reaction temperature 220 ℃. Under these conditions, the polydispersity index(PDI) was small. The structure and performance of the polyester was characterized by FT-IR, GPC, DSC, and TG. The results showed that HBP contained a large number of ester and hydroxyl groups; the number average molecular weight was 2 308; the temperature with thermal weight loss of 50% was 402 ℃; the glass transition temperature(T_g) was 42.9℃; the intrinsic viscosity was 2.11 mL/g. When the polymer was further modified by methacrylic acid, the obtained hyperbranched polyester contained terminal vinyl groups(VHBP). The structure and performance of VHBP was characterized by FT-IR, DSC, and TG. The results showed that VHBP contained terminal vinyl groups; the temperature of 50% thermal weight loss was 379 ℃; the T_g was -31.78 ℃; the intrinsic viscosity was 1.1 mL/g. HBP and VHBP had good solubility. The UV-cured film of VHBP had good flexibility and resistance to water, alcohol, and alkali. And the adhesion force was 1 grade; the impact resistance was over 50 kg/cm; gel rate was 85%; film hardness by pencil was 3H.

Key words: maleopimaric acid, rosin based hyperbranched polyester, terminal-vinyl hyperbranched polyester, UV curing