Polymerization of A₂ with B₃ monomers: A facile approach to hyperbranched poly(aryl ester)s

Hyperbranched polymers have received significant attention due to their unique combination of low viscosity, excellent solubility, and facile synthesis. This paper describes an efficient approach to hyperbranched poly(aryl ester)s via the polycondensation of A₂ and B₃ monomers. A dilute bisphenol A (A₂) solution was added slowly to a dilute 1,3,5-benzenetricarbonyl trichloride (B₃) solution at 25°C to prepare hyperbranched poly(aryl ester)s in the absence of gelation. The molar ratio of A₂:B₃ was maintained at 1:1, and the maximum final monomer concentration was ∼0.08 M. ¹H NMR spectroscopy and derivitization of terminal groups indicated that the phenol functionalities were quantitatively consumed during the polycondensation. Two model compounds were synthesized to identify ¹H NMR resonances for linear, dendritic, and terminal units, and the final degree of branching was determined to be ∼50%. Moreover, the hyperbranched polymers exhibited lower glass transition temperatures relative to their linear analogues.