Polymerization of methyl methacrylate in the presence of ferric nitrate

Abstract

Abstract The polymerization of methyl methacrylate in the presence of ferric nitrate was studied. In spite of the conventional concept that the ferric salt is an inhibitor, the rate of polymerization was found to increase with increasing concentration of ferric nitrate in the range below 1.0·10 −3 mole·1 −1 , and is represented by An interaction between methyl methacrylate and ferric salt was detected by means of visible and infrared absorption spectra. As the effect of ferric salt shows up in the CO band rather than CC band, the ferric salt is considered to coordinate to the oxygen of the carbonyl group of methyl methacrylate to form a complex. The polymerization reaction proceeds via a radical mechanism, and probably is initiated by the decomposition of the complex. On the copolymerization of methyl methacrylate with styrene and methacrylamide, no effect of ferric salt is observed with respect to the compositions of the resulting copolymers. It is considered that the ferric salt initiates the polymerization only within a range of its lower concentrations. At higher concentrations, the ferric salt terminates the polymerization.