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The photoinduced polymerization of acrylic monomers using dyes in a protein-restricted medium is reported. We studied dyes of different families as potential polymerization catalysts, exploiting the observation that the photophysical properties of some dyes are altered when bound to biopolymers. The light induced polymerization of acrylic monomers in the presence of bovine serum albumin or gelatin using triphenylmethane and azo dyes proceeded smoothly. Using GE Miser 120 W spotlights as a convenient illumination source, we found polymerization could be achieved in some cases within 60 min of irradiation. The polymerization rates were found to be dependent on the concentrations of the dye and the protein. In the absence of protein or dye polymerization was virtually non-existent. When the reaction mixture was blanketed with nitrogen, polymerization was observed to be faster than that that in air equilibrated samples. We believe these photopolymerizations may proceed via a free-radical pathway. Our results suggest the possible role of some of these dyes as polymerization catalysts, though they had previously seemed inert in fluid solutions. [ABSTRACT FROM AUTHOR]

The photocatalytic bleaching of dyes using TiO2 has appeared promising in laboratory studies, but little attention has been focused on whether other species such as might be found in wastewater have a deleterious effect on the photobleaching. This study describes the effects that result from the presence of ionic species, organic solvents and humic substances on the photobleaching of several dyes. The manner in which the photobleaching was affected by the presence of adventitious materials was carefully examined with an eye toward elucidating the mechanistic origin of the loss of the photochemical efficiency in the reaction. The overall retardation effects can be attributed to the combination of light attenuation, inhibition and competition effects. [Copyright &y& Elsevier]