Rheological properties of three different microstructures of water-soluble polymers prepared by solution polymerization

Polymer chains consisting of water-soluble polyacrylamides hydrophobically modified with low amount of hydrophobic groups, with varying hydrophobic chain structure (C-16 and C-di8) and with varying localization of the hydrophobe along the chain (telechelic, multisticker, and combined polymers) were investigated. The viscoelastic behavior of these associative polymers has been studied in semidilute solutions using steady-flow and oscillatory experiments. The effect of type and localization of the hydrophobic groups on the viscosity of the associative polymer solution was investigated. It can be inferred that the high viscosity presented by these polymers, is due largely to G (0), which represents the number of associations in the medium at any given time and less so on T (R), which represents the duration time of any given association. On all studied samples, T (R) as well as G (0), were affected by the type (di-substituted or linear) and localization of the hydrophobic groups (telechelic, multisticker, or combined).