A Convenient Room Temperature Polycondensation Toward Hyperbranched AB2-Type All-Aromatic Polyesters with Phenol Terminal Groups

As a convenient alternative to the classical melt polycondensation the one-pot solution polycondensation of suitable AB(2) monomers under mild conditions has been successfully adapted to hyperbranched all-aromatic polyester with phenol terminal groups. The polymerization was performed in solution at room temperature directly using commercially available 3,5-dihydroxybenzoic acid as monomer and 4(dimethylamino) pyridinium 4-tosylate as catalyst to suppress the formation of N-acylurea. Different carbodiimides as coupling agents were investigated to find the optimal esterification conditions. The polymers have been characterized extensively and were compared with their well-known analogs synthesized in melt. The characterization was carried out by NMR spectroscopy, size exclusion chromatography, and asymmetric flow-field flow fractionation as an alternative separation technique for multifunctional polymers. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47:5158-5168, 2009