Oxygen-ascorbic acid-Copper(II) initiating system. A kinetic study of the polymerisation of methyl acrylate in aqueous medium

Polymerisation of methyl acrylate (MA) initiated by O2-ascorbic acid (AA)-Cu2+ system was studied in aqueous medium at 40°C. The rate of polymerisation Rp, was found to increase, remain constant, and then decrease with increasing [Cu2+]. Rp was found to depend on [Cu2+]0,6, [AA]0, [O2]0,6, and [MA]1,3 in the increasing region, on [Cu2+]0, [AA]0, [O2]0,6, and [MA]1,6 in the constant region and on [Cu2+]-0,9, [AA]0, [O2]0,7, and [MA]2,0 in the decreasing region. Rate laws were derived assuming a plausible reaction mechanism for the different regions. Rp increased with ionic strength and decreased with [H2SO4,]. An initial increase, then steady state followed by a decrease in rate with temperature was noticed in the range 25-55°C. kp/kt½ values were calculated and compared with literature values. Chain lengths were determined viscometrically