The influence of mono and divalent cations on dilute and non-dilute aqueous solutions of sodium alginates

A broad study of the viscous behavior of three different sodium alginates in dilute and non-dilute solution in the presence of different electrolytes has been performed. In dilute solutions, we have determined the molecular weight of three different samples of sodium alginate from the same source through the Mark–Houwink–Sakurada equation. We have confirmed for the three chains the Pals–Hermans relation in a wide range of ionic strength. The quality of the solvent in this range of ionic strength has also been studied. For non-dilute systems, we have evaluated the behavior of alginates not only in salt-free conditions but also with the addition of monovalent and divalent cations. The transition from Newtonian to non-Newtonian behavior and the variation of the viscosity have been found to be profoundly affected by the addition of these electrolytes.