Abstract

The rate of polymerization of 2-hydroxyethyl methacrylate in aqueous media, photoinitiated by aliphatic azo compounds, is proportional to the monomer concentration and the square root of the photosensitizer concentration. These results are indicative of a simple photoinitiation mechanism, in which the monomer does not interfere with the photoinitiator cleavage and the primary radicals add quantitatively to the monomer. The polymerization rate has been measured for a series of solvents and solvent mixtures. The rate correlates with the cohesive energy of the co-solvent, being faster in monomer/water mixtures. The high rates in these systems are explained in terms of the polymer conformation and solvophobic effects. Copyright © 1996 Elsevier Science Ltd.