Research on Improving the Efficiency and Spectral Response of Photopolymerization

摘要

The ultimate objective of this research program is the development of a nonsilver halide photographic process based upon photopolymerization. Work toward this goal was in three main areas: (1) study of the effects of viscosity on photopolymerization; (2) elimination of oxygen inhibition; and (3) evaluation of efficient visiblelight-activated free-radical initiator systems. Studies into the kinetics of photopolymerization of acrylamide in gelatin slabs as a function of water content and the nature of the activator molecule showed that efficient polymer yields and molecular weights were obtained at water levels of 30% to 85%, but lower yields were obtained at lower water levels. Oxygen removal was investigated with bisulfite ion, oxygen-carrying metal chelates, and enzymes. Although the bisulfite approach appears useless, the other two procedures warrant additional investigation. A re-evaluation of the kinetics and mechanism of photopolymer processes activated by acetylacetone and dimedon indicated that photoinitiation results from the reaction with the monomer of a lightexcited thionine-B-diketone complex. (Author)