A Benzophenone-Naphthalimide Derivative as Versatile Photoinitiator of Polymerization Under Near UV and Visible Lights

A benzophenone-naphthalimide derivative (BPND) bearing tertiary amine groups has been developed as a high-performance photoinitiator in combination with 2,4,6-tris(trichloromethyl)-1,3,5-triazine or an iodonium salt for both the free radical polymerization (FRP) of acrylates and the cationic polymerization (CP) of epoxides upon exposure to near UV and visible LEDs (385-470 nm). BPND can even produce radicals without any added hydrogen donor. The photochemical mechanisms are studied by molecular orbital calculations, steady state photolysis, electron spin resonance spin trapping, fluorescence, cyclic voltammetry and laser flash photolysis techniques. These novel BPND based photoinitiating systems exhibit an efficiency higher than that of the well-known camphorquinone-based systems (FRP and CP) or comparable to that of bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide (FRP at 455 nm). (c) 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 445-451