Polymeric amine bearing side-chain thioxanthone as a novel photoinitiator for photopolymerization

Abstract

Novel polymeric photoinitator (PTX) was synthesized by introducing thioxanthone (TX) moieties to polymeric amine side-chain. Compared with low-mulecular weight model compound, PTX has similar UV–vis absorption and weaker fluorescence emission, and some radicals are trapped in the macromolecular coil cage. The kinetics for polymerization of trimethylolpropane triacrylate using PTX as photoinitiator was studied by photo-DSC. It shows that PTX is an efficient photoinitiator, and that PTX concentration and light intensity have similar effect on photopolymerization. The increase in PTX concentration and light intensity leads to the increase in the polymerization rate and the final conversion. The increase in temperature also results in the increase in the polymerization rate and final conversion, due to the enhanced molecular mobility and delay in vitrification at high temperature. At the late stage of polymerization, the reaction becomes more diffusion-controlled than that at early stage of polymerization.