POLYMERIZATION OF 2-HYDROXYETHYL METHACRYLATE INDUCED BY AZO-COMPOUNDS - SOLVENT EFFECTS

The rate of polymerization of 2-hydroxyethyl methacrylate in aqueous m edia, photoinitiated by aliphatic azo compounds, is proportional to th e monomer concentration and the square root of the photosensitizer con centration. These results are indicative of a simple photoinitiation m echanism, in which the monomer does not interfere with the photoinitia tor cleavage and the primary radicals add quantitatively to the monome r. 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 a nd solvophobic effects. Copyright (C) 1996 Elsevier Science Ltd