The effect of ionic strength on copolymerization of acrylamide with sodiumsalt 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) initi ated by a potassium peroxosulfate-sodium bisulfite system and carried out a t 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 init ially grows as the ionic strength increases and then remains unchanged with an increase in the concentration of M-2. The molecular mass of the resulti ng copolymer grows with an increase in the concentration of the comonomers and drops upon the addition of NaCl. It was demonstrated that the content o f 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.