Journal of Polymer Science Part A: Polymer Chemistry, Vol.46, No.16, 5414-5430, 2008
Hydroxyl-terminated hyperbranched aromatic poly(ether-ester)s: Synthesis, characterization, end-group modification, and optical properties
Novel AB(2)-type monomers such as 3,5-bis(4-methylolphenoxy)benzoic acid (monomer 1), methyl 3,5-bis(4-methylolphenoxy) benzoate (monomer 2), and 3,5-bis(4-methylolphenoxy)benzoyl chloride (monomer 3) were synthesized. Solution polymerization and melt self-polycondensation of these monomers yielded hydroxyl-terminated hyperbranched aromatic poly(ether-ester)s. The structure of these polymers was established using FTIR and H-1 NMR spectroscopy. The molecular weights (M-w) of the polymers were found to vary from 2.0 x 10(3) to 1.49 x 10(4) depending on the polymerization techniques and the experimental conditions used. Suitable model compounds that mimic exactly the dendritic, linear, and terminal units present in the hyperbranched polymer were synthesized for the calculation of degree of branching (DB) and the values ranged from 52 to 93%. The thermal stability of the polymers was evaluated by thermogravimetric analysis, which showed no virtual weight loss up to 200 degrees C. The inherent viscosities of the polymers in DMF ranged from 0.010 to 0.120 dL/g. End-group modification of the hyperbranched polymer was carried out with phenyl isocyanate, 4-(decyloxy)benzoic acid and methyl red dye. The end-capping groups were found to change the thermal properties of the polymers such as T, The optical properties of hyperbranched polymer and the dye-capped hyperbranched polymer were investigated using ultraviolet-absorption and fluorescence spectroscopy. (C) 2008 Wiley Periodicals, Inc.
Keywords:degree of branching;end-group modification;functionalization of polymers;hyperbranched;hyperbranched aromatic poly(ether-ester)s;hyperbranched polymer;light-emitting materials;optical properties;polyesters