The influences of the irradiation temperature, comonomer content, sample thickness, and photoinitiator concentration on the polymerization kinetics of hyper-branched acrylated aromatic polyester (HAAPE) were investigated with photo-differential scanning calorimetry and IR measurements. The maximum photopolymerization rate increased with the temperature rising up to 110degreesC but decreased beyond 110degreesC. An activation energy of 16 kj mol(-1) for the photopolymerization was obtained below 110degreesC from an Arrhenius plot, but it was negative beyond 120degreesC. A remarkable synergistic effect between HAAPE and the comonomer trimethylolpropane triacrylate with a molar fraction of around 0.4 was observed from a photopolymerization kinetic study of the resins. The final unsaturation conversion in an ultraviolet-cured film decreased with the sample thickness, and this became more remarkable as the photoinitiator concentration increased. (C) 2003 Wiley Periodicals, Inc.