4-methyl-4-[2-(naphthalene)-2-oxoethyl] morpholin-4-ium iodide as a water soluble photoinitiator

Abstract

Quaternary ammonium salt namely 4-methyl-4-[2-(naphthalen-2-yl)-2-oxoethyl] morpholin-4-ium iodide (WSMPM) was synthesized and characterized. High molar absorptivity at 347 nm (1910 L･mol-1･cm-1) and good solubility in distilled water (10-2 M) allows WSMPM to be used as an effective photoinitiator also in water-soluble systems. Photopolymerization of acrylamide monomer with WSMPM (10-3 M) and a tertiary amine (N-methyldiethanolamine), resulted in 84.4% monomer to polymer conversion. Based on laser photolysis and electron spin resonance, a photoinitiator mechanism was proposed.