Water-Soluble Polymers .60. Synthesis and Solution Behavior of Terpolymers of Acrylic Acid, Acrylamide, and the Zwitterionic Monomer 3-[(2-Acrylamido-2-Methylpropyl)Dimethylammonio]-1-Propanesulfonate

Terpolymers of acrylic acid (AA), acrylamide (AM), and the zwitterionic monomer 3-[(2- acrylamido-2-methylpropyl)dimethylammonio]-l-propanesulfonate (AMPDAPS) have been prepared by the free-radical polymerization in a 0.5 M NaCl aqueous solution using potassium persulfate as the initiator. The feed ratio of AMPDAPSAA:AM was varied from 5:590 to 402020 mol % , with the totalmonmer concentration held constant at 0.45 M. Terpolymer compositions were obtained by ‘9c NMR. Low-angle laser light scattering provided molecular weights and second virial coefficients which varied from (3.0 to 7.9) X 106 and (2.23 to 2.95) X 10-4 mL mol g2, respectively. The solubilities of the resulting terpolymers are dependent on pH as well as the amount of AMPDAPS and AA present in the feed. At pH 4 and for higher incorporation of AA and AMPDAPS in the feed (\u3e25 mol %), the terpolymers are insoluble in deionized water and 0.25 M NaC1. At pH 8, all terpolymers are soluble in deionized water and salt solutions. The dilute and semidilute solution behavior of the terpolymers were studied as a function of composition and added electrolytes. Polyelectrolyte behavior was observed for all terpolymers at pH 8 as evidenced by a viscosity decrease in the presence of added electrolytes. The terpolymers exhibit higher viscosities in the presence of NaSCN versus NaC1. Comparison of the solution behavior of the terpolymers to copolymers of AM and AA as well as copolymers of AMPDAPS and AM has been made