Photoinitiation Mechanism and Ability of Thioxanthone‐Based Versatile Visible Photoinitiators

Abstract The development of visible photoinitiating systems is attracting increasing attention due to their great applications in various fields. Three thioxanthone (TX) derivatives differing by their substituent groups are investigated as photoinitiators (PIs) for visible photopolymerization. They can be used as one‐component PIs to initiate free radical polymerization. Furthermore, a two‐component system with an iodonium can initiate cationic polymerization and hybrid polymerization and could make interpenetrating polymer networks synthesis. The high efficiency of these systems is found as being worthwhile for photocomposites preparations. Moreover, the mechanism of these TX derivatives is clarified using computational quantum chemistry, fluorescence quenching, steady‐state photolysis, cyclic voltammetry, and electron spin resonance spin‐trapping techniques.