Synthesis and characterization of triarylsulfonium salts as novel cationic photoinitiators for UV-photopolymerization

Using diaryliodonium salts as the arylating reagent and copper as a catalyst, a series of triarylsulfonium salts bearing benzoyl or benzoheterocyclic moieties were synthesized and characterized by H-1 NMR, C-13 NMR and high-resolution mass spectrometry. The photoinitiating behavior of the triarylsulfonium salts on photopolymerization of epoxy acrylate resin (UV6104) with hexane-1,6-diyldiacrylate (HDDA) as an activated monomer was investigated. The results showed that these triarylsulfonium salts could be utilized as cationic photoinitiators in the UV-curing process. A polymerization photoinitiation mechanism has been proposed.