One-pot synthesis and characterization of hyperbranched poly(ester-amide)s from commercially available dicarboxylic acids and multihydroxyl secondary Amines

A convenient and cost-effective strategy for synthesis of hyperbranched poly(ester-amide)s from commercially available dicarboxylic acids (A(2)) and multihydroxyl secondary amine (CB2) has been developed. By optimizing the conditions of model reactions, the AB(2)-type intermediates were formed dominantly during the initial reaction stage. Without any purification, the AB(2) intermediate was subjected to thermal polycondensation in the absence of any catalyst to prepare the aliphatic and semiaromatic hyperbranched poly(ester-amide)s bearing multi-hydroxyl end-groups. The FTIR and H-1 NMR spectra indicated that the polymerization proceeded in the proposed way. The DBs of the resulting polymers were confirmed by a combination of inverse-gated decoupling C-13 NMR, and DEPT-135 NMR techniques. The DBs of the hyperbranched poly(ester-amide)s were in the range of 0.44-0.73, depending on the structure of the monomers used. The hyperbranched polymers exhibited moderate molecular weights with relatively broad distributions determined by SEC. All the polymers displayed low inherent viscosity (0.11-0.25 dL/g) due to the branched nature. Structural and end-group effects on the thermal properties of the hyperbranched polymers were investigated using DSC. The thermogravimetric analysis revealed that the resulting polymers exhibit reasonable thermal stability. (C) 2008 Wiley Periodicals, Inc.