Green Bulb Light Source Induced Epoxy Cationic Polymerization under Air Using Tris(2,2′-bipyridine)ruthenium(II) and Silyl Radicals

An approach for the cationic ring-opening polymerization of epoxy monomers using a system based on Ru(bpy)32+ and a very convenient green fluorescence bulb irradiation device was proposed. The EPOX films (25 μm thick) deposited on a BaF2 pellet were irradiated under air inside the IR spectrometer cavity. The stability of the prepared formulations was excellent when the two silanes, tris(trimethylsilyl) silane (TTMSS), diphenylsilane (DPS), were used as additives for the cationic photo-polymerization. ESR-Spin Trapping (ST) experiments were carried out using X-band spectrometer and the radicals were produced under a xenon lamp exposure and trapped by phenyl-N-tert-butyl nitrone (PBN). A good to excellent polymerization was observed when a green bulb irradiation and the Ru/TTMSS/diphenyliodonium hexafluorophosphate (Ph2I+) three-component photoinitiating system was used.