Hyperbranched polyesters based on polycondensation of 1,3,5‐tris(2‐hydroxyethyl) cyanuric acid and 3,5‐dihydroxybenzoic acid

A series of hyperbranched polyesters was produced by the condensation of the monomer 3,5-dihydroxybenzoic acid with 1,3,5-tris(2-hydroxyethyl) cyanuric acid as a trifunctional central core. The monomer-to-core ratio was varied between 3 and 45. The resulting polymers were phenolic-terminated polyesters. The degree of branching of the polyesters was calculated according to the method described by Frechet and was found to be in the range of 0.7–0.8. The number-average molecular weights calculated via 1H NMR spectroscopic degree-of-polymerization values are in reasonable agreement with the predicted values derived from the monomer-to-core ratio for all prepared polyesters. Thermal and photophysical properties were also studied. Glass-transition temperatures were determined by differential scanning calorimetry and were found to be relatively independent of the theoretical molar mass. The polyesters were found to be blue emitters, and the solutions exhibited intense fluorescence, with a maximum of 430 nm. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3278–3288, 2005