Benzophenone/triethylamine-photoinitiated polymerization of methyl acrylate

Benzophenone-sensitized photopolymerization of methyl acrylate was shown to be remarkably enhanced by the addition of small amounts of triethylamine. This was attributed to the efficient formation of an electron-transfer complex between photoactivated benzophenone and ground-state amine. Ketyl and amine free radicals derived from this complex were postulated to be the chain-initiating species. Quantum yield experiments indicated that methyl acrylate itself was also a quencher of the benzophenone triplet state.