Heterocyclic ylide initiated photopolymerization of methyl methacrylate

Abstract

Solution polymerization of methyl methacrylate (MMA) was carried out in the presence of visible light (440 nm) using β-picolinium p-chlorophenacylide as a photoinitiator at 30°C. The initiator and monomer exponent values were calculated to be 0·5 and 1·0 ± 0·01, respectively. An average value of $\text{k}{}_{\mathrm{p}}{}^2\text{k}{}_{\mathrm{t}}$ was 4·07 × 10⁻². The polymerization was retarded in the presence of hydroquinone; however, a nonpolar solvent (cyclohexane) enhanced the rate of polymerization. Kinetic data and ESR studies indicate that the overall polymerization takes place by a radical mechanism via triplet carbene formation which acts as a source of free radicals.