Radical Polymerization of Alkali Acrylates in Aqueous Solution

Abstract

Monomer conversion versus time profiles for the radical polymerization of ionized acrylic acid (AA), 0.6 to 0.8 mol L-1 in aqueous solution, are measured at 50 degrees C via inline near-infrared spectroscopy mostly on fully ionized AA, i.e., of alkali acrylates. Ionization reduces polymerization rate with the size of this effect being dependent on the type and on the concentration of the alkali counter cation, which is varied from lithium to rubidium. Polymerization rate becomes very small upon shielding the cation by complexation, whereas an enhancement of cation concentration, by addition of alkali chloride, may enhance polymerization rate such as to even reach the high rates observed with the radical polymerization of nonionized AA.