PHOTOPHYSICS AND PHOTOCHEMISTRY OF P-NITROANILINE AS PHOTOINITIATOR

Steady-state (313 and 365 nm) and laser (308 and 337 nm) photolysis ha ve been employed to carry out a structure-reactivity investigation on p-nitroaniline as photoinitiator of polymerization. Detailed studies o n the spectroscopy of the molecule were accomplished. Quantum yields o f p-nitroaniline photoreduction induced by a tertiary amine, 2-(N,N-di ethylamino) ethanol have been determined. The dependence of the photor eduction behaviour on several factors, such as photoinitiator concentr ation, proportion of the aliphatic amine added to p-nitroaniline as re ducing agent, nature of the coinitiator, irradiation energy, and wavel ength has been studied. The analysis by gas chromatography-mass spectr oscopy technique of the photolysed solutions allowed 1,4-benzenediamin e to be identified as the main photoreduction product. A mechanism for the p-nitroaniline photoreduction induced by the aliphatic amine is s uggested. (C) 1997 Elsevier Science S.A.