Polymerization of mathacrylamide photo initiated by trans diazidotetraminecobalt (III) azide

Abstract

The kinetics of polymerization of methacrylamide in aqueous solution photoinitiated by trans-diazidotetramminecobalt(III)azide was systematically studied at 35°C and pH≈3. Monochromatic radiations of λ=365, 405, and 435 mμ were employed. The rate of monomer disappearance was followed bromometrically and the rate of complex disappearance spectrophotometrically. The effect of variables such as monomer concentration, light-absorption fraction by the complex, light intensity, and wave length on the kinetics was studied. The rate of polymerization was found to be proportional to the monomer concentration and independent of the light-absorption fraction (k_ε) and light intensity (I). A kinetic scheme consisting of (1) a primary photochemical act of excitation of the complex followed by electron transfer producing the azide radical, (2) initiation of polymerization by the azide radical, and (3) termination of the chain process by the excited complex molecules is proposed and discussed in the light of experimental results.