Design of a polymerizable dithioaniline derivative with double functions of reducing volume shrinkage and initiating polymerization for LED photopolymerization

Abstract

This work reports a photopolymerizable dithioaniline derivative (OMABS), having the double functions of reducing volume shrinkage and initiating polymerization under light emitting diode (LED) irradiation. Its photochemistry and photoinitiation properties were investigated by UV–vis absorption spectroscopy, electron paramagnetic resonance spectroscopy (EPR), real-time infrared spectroscopy (RTIR) and confocal micro-Raman spectroscopy. OMABS shows a weak absorption around 385 nm and 405 nm, but can generate arylthiyl radicals to effectively initiate the polymerization of bisphenol A glycerolate dimethacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) system and itself under 385 and 405 nm LED irradiation, and the double bond conversion reaches up to 83.2 %. Significantly, OMABS can obviously reduce the volume shrinkage of Bis-GMA/TEGDMA system, and the volume shrinkage (4.89 %) of Bis-GMA/TEGDMA with OMABS system declines by almost half compared with that (8.10 %) without OMABS system due to the existence of dynamic reversible SS bond and intermolecular hydrogen bonding interaction. Moreover, OMABS has little influence on the gel yield, thermal stability and frictional resistance of the Bis-GMA/TEGDMA system.