Kotsuba T. Kinetics and Interaction Mechanism Between Photoexited Alkylaminobenzophenones and Butyl Methacrylate.

This paper devoted to study of photochemical and photophysical processes with alkylamino benzophenones in solutions of various polarity and their role in processes of initiation of polymerization of akryl monomers. Alkylaminoderivatives of benzophenone was shown to reveal fluorescence, the maximum of fluorescence spectra being substantionally shifted to red. Transition into fluorescence state is combined with substantinal charge transfer, approved by calculated dipol moment. Photochemical processes with participation of benzophenone-Michler's ketone pair in vacuum and in the presence of oxygen of air, and role of intermediates of these processes in photopolymerisation of monomer were studied. Correspondence between iduction period and s-Gammet constant of benzophenone substituent in solution of various polarities was found. The idea of possibility of formation of threefold donor-acceptor complex was put forward, dioxygen being transmitter of electrons as well as deprotonating agent. The nature and kinetic aspects of formation and decay of intermediates was studied by method of flash photolysis, appeared at photoexitation of alkylaminoderivatives of benzophenone at the absence and in the presence of monomer. It was shown for the first time that in polar solvent long lived polar intermediate appears, ascribed to intermolecular charge transfer state. The conclusion was made about free radical mechanism of polymerisation of butylmethacrylate promoted by initiator in mention. Using experimental and literature data the mechanism of photopolymerisation sensibilized by alkylaminoderivatives of benzophenone dependent on the polarity of a solvent was proposed.