The synthesis of thioxanthone-benzotriazole as a one component photoinitiator and the investigation of this initiator in photopolymerization

3H-5-Thia-1,2,3-triaza-cyclopenta[b]anthracene-10-one (TX-BT) was synthesized as a novel photoinitiator based on thioxanthone structure. TX-BT has one component photoinitiator character. Photopolymerization experiments were performed for Methyl methacrylate (MMA) as monomer by using of various concentrations of TX-BT in Dimethylformamide (DMF) with or without N-Methyldiethanolamine in either air or nitrogen atmosphere. NMDEA were added for the formulatios where experiments were performed under air. Photocuring of multifunctional acrylates were also performed for Trimethylolpropanetriacrylate (TMPTA) and Epoxyacrylate (EA + % 25 Tripropyleneglycoldiacrylate) at three different concentrations of TX-BT in the presence of NMDEA by using of Photo Differantial Scanning Calorimeter (Photo- DSC). The same formulations were coated on tracing paper as a 12 ? thickness and cured until no visible deformation was observed by Mini-UV-Cure Unit; the speed of belt of Mini-UV-Cure Unit was employed as 15-50 m/min . Real Time Fourier Transform Infrared Spectroscopy (RTFTIR) were also used to find out the rate of polymerization and conversion percentages of multifunctional acrylates with TX-BT in the presence of NMDEA. Photobleaching of TX-BT were recorded for certain period of irradiation time by using of medium pressure mercury lamp. It was observed that TX-BT consumed totally after 120 seconds irradiation time in the presence of NMDEA. Fluorescence quantum yield was calculated as fF= 0.178 when diphenylanthracene was used as standard and excitation and emission spectrum of TX-BT was obtained as mirror image of each other when solution was excited at 380 nm. Key Words: Photoinitiator, free radical polymerization, 3H-5-Thia-1,2,3-triazacyclopenta[ b]anthracene-10-one (TX-BT), photopolymerization