Blue LED Light-Sensitive Benzo Pyrazolo (or Imidazo) Isoquinolinone Derivatives in High-Performance Photoinitiating Systems for Polymerization Reactions

Isoquinolinone derivatives (IQ) have been synthesized and combined with different additives (an amine, 2,4,6-tris(trichloromethyl)-1,3,5-triazine, an iodonium salt, or N-vinylcarbazole) to produce reactive species (i.e. radicals and cations) being able to initiate the radical polymerization of acrylates, the cationic polymerization of epoxides, the thiol-ene polymerization of trifunctional thiol/divinylether, and the synthesis of epoxide/acrylate interpenetrated polymer network IPN upon exposure to very soft polychromatic visible lights, blue laser diode or blue LED lights. Compared with the use of camphorquinone based systems, the novel combinations employed here ensures higher monomer conversions (approximate to 50-60% vs. approximate to 15-35%) and better polymerization rates in radical polymerization. The chemical mechanisms are studied by steady-state photolysis, fluorescence, cyclic voltammetry, laser flash photolysis, and electron spin resonance spin trapping techniques. (c) 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 567-575