Water-soluble polymers: 33. Ampholytic terpolymers of sodium 2-acrylamido-2-methylpropanesulphonate with 2-acrylamido-2-methylpropanedimethylammonium chloride and acrylamide: synthesis and aqueous-solution behaviour

Abstract

Synthesis and viscometric studies of a series of moderate-to-low charge-density terpolymers of acrylamide (AM) with sodium 2-acrylamido-2-methylpropanesulphonate (NaAMPS) and 2-acrylamido-2-methyl-propanedimethylammonium chloride (AMPDAC) have been conducted. Plots of apparent viscosity versus polymer concentration revealed critical overlap concentrations ($\text{C∗}$) in the range 0.10–0.14 g dl⁻¹. The dependence of the reduced viscosity of the terpolymers on temperature was minimal, with only a slight decrease in viscosity observed with increasing temperature. Reduced viscosity was shown to be a function of polymer composition, charge distribution and molecular weight of the terpolymers. The low-to-moderate charge-density terpolymers of NaAMPS with AMPDAC displayed viscosities over 100% greater than the high charge-density copolymers. The superior viscometric characteristics of the terpolymers became more evident as the polymer concentration approaches $\text{C∗}$