Rheological properties and gel formation of aqueous salt-containing solutions of sodium poly(5-vinyltetrazolate) in the presence of Cr3+ ions

The rheological properties of dilute and moderately concentrated aqueous so lutions of sodium salt of poly(5-vinyltetrazole) were studied in the presen ce of a high content of a low-molecular-mass electrolyte. As was found, at high ionic strength of aqueous salt-containing solutions (c(s) > 2 mol/l), the intrinsic viscosity of polymer is not a linear function of c(s)(-0.5). A transition from a dilute to moderately concentrated solution takes place when the concentration of polyelectrolyte is two times higher than the conc entration of crossover as estimated from the reciprocal intrinsic viscosity of the polymer. The process of gel formation in aqueous salt-containing so lutions of tetrazole-containing polymers in the presence of chromium (III) salts was studied. The minimum concentration of polymer at which gel format ion takes place coincides with the concentration boundary of the formation of a fluctuation entanglement network in the initial aqueous salt-containin g solution.