A Novel Three-Component System in Visible Light Photo-induced Polymerization.

Enhanced visible radiation photopolymerization of dimethacrylates with the three component thioxanthone (CPTXO)–amine–iodonium salt system

“…These include enhanced polymerization rates at lower light intensities, 18,41 greater flexibility in selection of the components 41 and the ability to initiate free-radical and cationic photopolymerizations simultaneously. 46,47 However, in contrast to the two component redox photoinitiators, the three component systems are not well understood, and a number of different mechanisms using an onium salt have been proposed in the literature 11,[17][18][19]22,23,[29][30][31][32][33]39,41,48 which can be loosely grouped into two general classes. The first category applies to parallel systems where two of the three components are involved in one initiating process while a second pair of the three components react via an independent process to form other initiating species.…”

“…11,19,30,39 The second category applies to sequential reactions in which two of the three components first react with one another and the third component then reacts with the products of the first reaction. 17,18,22,23,29,[31][32][33]41 As an example of parallel initiation, Padon and Scranton 19 studied a three-component system containing Eosin Y, N-methyldiethanolamine, and diphenyliodonium chloride. Based on the photo-DSC kinetics studies and laser-induced fluorescence experiments, it was concluded that there are simultaneous ( parallel) reactions between the eosin and iodonium and between the eosin and amine.…”

Polymerization kinetics of phosphonic acids and esters using an iodonium initiator

“…In our previous studies of the polymerization kinetic and bond strength of SEAs, we employed the camphorquinone (CQ)/amine photo redox initiator system, because it is commonly used for photoinitiation of dental restoratives . Recently, three‐component photoinitiator systems have emerged because they provide much faster photopolymerization . These systems are commonly composed of a light absorbing moiety (such as CQ), an electron donor (often an amine) and an oxidizing onium salt such as a iodonium salt.…”