The effect of ionic strength on copolymerization of acrylamide with sodium salt of 2-acrylamido-2-methylpropanesulfonic acid in aqueous solutions

The kinetics of homogeneous free-radical copolymerization of acrylamide (M-1) and sodium salt of 2-acrylamido-2-methylpropanesulfonic acid (M-2) initiated by a potassium peroxosulfate-sodium bisulfite system and carried out at pH 9 and 50 degrees C in water and aqueous solutions of NaCl was studied. It was shown that the rate of copolymerization and the reaction order with respect to M-2 increase as the concentration of this monomer increases and upon addition of NaCl. The apparent rate constant of copolymerization initially grows as the ionic strength increases and then remains unchanged with an increase in the concentration of M-2. The molecular mass of the resulting copolymer grows with an increase in the concentration of the comonomers and drops upon the addition of NaCl. It was demonstrated that the content of M-2 units in the copolymer increases as the concentration of M-2 in the (M-1 + M-2) mixture increases and as the content of NaCl grows.