Formulation and Characterization of epoxidized hydroxyl-terminated hyperbranched polyester and its application in waterborne epoxy resin

A novel epoxidized hydroxyl-terminated hyperbranched polymer (HPEEX) was formulated from epichlorohydrin and hydroxy-terminated hyperbranched polyester (HPE) based on trimethylol propane (TMP) and AB(2) monomer. The obtained HPEEX was characterized with FT-IR, (HNMR)-H-1 spectroscopy, TG, WAXD and GPC analysis. Results showed that the HPEEX was formulated as expected and its molecular weight and intrinsic viscosity were 3,789 g/mol and 3.96 mL/g, respectively. Meanwhile, the HPEEX was used as cross-linking agent in the preparation of waterborne epoxy resins. Performance of the HPEEX modified epoxy resin aqueous (EP-H) dispersions and their films was evaluated by various tests. It was found that with incorporation of hyperbranched polymer into the epoxy macromolecular chain, the EP-H films exhibited excellent hardness and water-proof performance: the hardness was as high as 96 (Shore A), and the contact angle of water on the surface of this kind of film was as high as 71A degrees, resulting from branched structure, higher functionality of HPEEX, better cross-linking density and large number of hydrogen bonding in this epoxy system.