A new visible light bimolecular photoinitiator system for free radical polymerization

A new bimolecular photoinitiator system consisting of a ferrocenium salt (Fc) and N-methyl-2-pyrrolidone (NMP) is developed for free radical photopolymerization under visible light irradiation, which was delivered by a halogen lamp. Photopolymerization profiles of tripropylene glycol diacrylate (TPGDA) show that high conversion can be easily achieved. The processes associated with the Fc/NMP system are investigated by photochemical and electrochemical experiments. The results show that the photoinitiation mechanism of this bimolecular system could occur through charge transfers between Fc and NMP.

► We develop a new bimolecular photoinitiator system consisting of a ferrocenium salt (Fc) and N-methyl-2-pyrrolidone (NMP) for free radical photopolymerization under visible light.
► The photoinitiation system of Fcs as free radical photoinitiators was simplified.
► The inherent problems of using dye as a photosensitizer was solved.
► Good initiation ability and high efficiency were found in this Fc/NMP system.
► An electron transfer process occurs between an Fc and NMP.