Studies in condensed phosphates. Part II. Viscosities of simple and complex sodium metaphosphate solutions

Publisher Website
Google Scholar
Abstract
The viscosity‐average molecular weights M̄w of [Na4Ca(PO3)6]n and [Na4Ba(PO3)6]n polymers determined by Staudinger's equation in 0.0035N NaCl solution were found to be lower than their number‐average molecular weights M̄n determined by endgroup titration. The above anomaly has been shown to be owing to the effect of bivalent cations liberated in equilibria of the type: This has been further confirmed by measurments of M̄w by the light scattering method. In aqueous solutions the greater change in viscosity of [Na4Ca(PO3)6]n solution with dilution is also ascribed to the secondary dissociation of the polymeric anions at lower concentrations.