Water-Soluble Copolymers .30. Effects of Molecular Structure on Drag Reduction Efficiency

Four series of high molecular weight, water-soluble acrylamide copolymers with specific compositions have been synthesized, characterized, and tested for drag reduction effectiveness. The comonomers sodium acrylate, sodium 2-(acrylamido)-2-methylpropanesulfonate, sodium 3-(acrylamido)-3- methylbutanoate, and diacetone acrylamide were utilized in appropriate molar ratios to provide tailored structures with varying degrees of hydrophobicity, ionic character, and propensity to form inter- or intramolecular associations. Drag reduction properties were measured in a modified rotating disk and a tube flow apparatus. A simple method of analyzing drag reduction performance was developed on the basis of hydrodynamic volume fraction normalization. This method allows comparison of diverse polymer types by efficiency curve superimposition utilizing an empirical shift factor. Drag reduction data were also analyzed by several conventional methods. Results demonstrate the dependence of drag reduction effectiveness on polymer structure as well as the importance of polymer-solvent interactions. Structure-performance analysis suggests that predictive theoretical models might be improved by inclusion of parameters reflective of solvent and associative interactions as well as hydrodynamic volume