Acridinediones: Effect of substituents on their photoinitiating abilities in radical and cationic photopolymerization

摘要

Ten acridinediones (ADs) with different substituents are prepared and investigated for their abilities to initiate a ring-opening cationic photopolymerization in combination with an iodonium salt and N-vinylcarbazole upon UV-vis light (Xe-Hg lamp; >330 nm) or visible light (halogen lamp) exposure. The structural effects in the ADs are outlined. The cationic and radical photopolymerization of an epoxide/acrylate blend in a one-step hybrid cure very efficiently leads to the formation of an interpenetrated polymer network under UV-vis light or visible light irradiation (30 s for tack-free coatings). The photochemical mechanisms are studied by molecular orbital calculations, steady-state photolysis, electron spin resonance-spin trapping, cyclic voltammetry, fluorescence, and laser flash photolysis techniques. Acridine-1,8-dione derivatives (AD) are proposed as new photinitators for polymerization under very soft irradiations (visible light, low intensity). These structures are high-performance photoinitiating systems for the ring-opening polymerization of epoxides and the radical photopolymerization of acrylates.