Real-time FTIR-ATR spectroscopy to study the kinetics of ultrafast photopolymerization reactions induced by monochromatic UV light

Real-Time FTIR-ATR spectroscopy was used to study the kinetics of photopolymerization reactions induced by monochromatic UV light. Various photoinitiator systems were tested for their efficiency to start the curing reaction of acrylates on irradiation at 313 or 222 nm. The effect of physical and chemical factors such as photoinitiator concentration, light intensity, temperature, monomer functionality and inertization on kinetic parameters like polymerization rate, induction period and final conversion was studied. The contribution of the postcuring to the final conversion was determined by following the decay of the double bonds during and after irradiation with single or multiple short UV flashes with a duration of 50-200 ms. Finally, some investigations of samples from practical applications such as UV-curable powder coatings, printing inks, and release coatings of silicone acrylates will be reported. (C) 1999 Elsevier Science B.V. All rights reserved.