FLOW PROPERTIES OF MODERATELY CONCENTRATED-SOLUTIONS OF CELLULOSE-ACETATE POLYMER

Calculations of rheological properties of polymeric solutions have usually been restricted to very dilute or to very concentrated solutions. In either case, one starts with a model for the microstructure. Between these two conceptual extremes lies the broad class of moderately concentrated solutions. To cover this region theoretically, two approaches have been used; 1) network theories focusing attention on entanglement junctions, and 2) single-molecule theories focusing attention on single molecules but including intermolecular interactions. Williams, Wang, and Zimm introduced a double model; one for a particular macromolecule and another for solutions containing like molecules in which the chosen macromolecule is suspended. This approach has turned out to be quite successful.