Preparation, characterization and modification of hyperbranched polyester-amide with core molecules

The synthesis of hyperbranched polyester-amides based on pentaerythritol (PETL) as a core molecule and AB2 monomer containing one carboxylic group and two hydroxylic groups using core-dilution/slow monomer addition strategy have been studied. The AB2 monomer was prepared by diisopropanolamine (DIPA) and cis-1,2-clyclohexane-dicarboxylic anhydride (HHPA). Two types of hyperbranched polyester-amide (1G-HP, 2G-HP) were obtained with the molar ratio of AB2 monomer and pentaerythritol (PETL) was 4 and 8, respectively. The structures of products were characterized by IR, 13C NMR, GPC and viscosity measurement. It was shown that the hyperbranched polymers prepared had high degree of branching (DB) and narrow molecular weight distribution. As for 1G-HP and 2G-HP, the intrinsic viscosity [η] was 4.32 ml/g and 5.29 ml/g, and the viscometric radius RV was1.28 nm and 1.67 nm, respectively. The results of viscosity measurement indicated that the structures of 1G-HP and 2G-HP were compacted and had a spherical conformation. In addition, the reactions of hydroxyl end-groups with polyethylene glycol monomethyl ether (mPEG550) and glycidyl methacrylate (GMA) were conducted to provide amphiphilic and UV-curable properties of resulting polymers. The properties of the modified hyperbranched polyester-amide were also investigated initially.