Aqueous polyurethane–alginate compositions: Peculiarities of behavior and performance

A series of polyurethane–alginate (APU/AG) compositions with pH/temperature-responsive character and regulated viscosity were obtained by adding different quantities of sodium alginate into an aqueous polyurethane anionic dispersion. Rheological, thermoresponsive, mechanical properties and swelling behavior dependencies on composition have been determined. APU/AG compositions reached equilibrium swelling and deswelling states within about 60 min. They display non-Newtonian flow and posses thixotropic properties. The strength of the films increases after their treatment with CaCl2 at the expense of cross-linking of alginate with divalent calcium ions and of forming an alginate network.