Studies on equilibrium swelling, dye adsorption, and dynamic shear rheology of polymer systems based on chitosan-poly(vinyl alcohol) and montmorillonite

Chitosan-poly(vinyl alcohol)/clay membranes were prepared by physical blending. These hybrid systems were characterized through infrared spectroscopy, microscopy, swelling, and oscillatory rheology. Adsorption of a commercial reactive dye by these membranes was further studied. Results showed that more stable blend membranes were formed due to the strong interaction in the polymers. These membranes showed substantial percent swelling in water and shrinking in saline solution. Adsorption analysis showed the ability of the blends to fix organic dyes, and to be used in liquid waste processing. In dynamic rheology, it was observed that all measured viscoelastic properties were influenced by polymer composition and clay content. For all samples, results show a typical behavior of an entangled system in the case of low concentrated macromolecular viscoelastic fluids. The dynamic moduli exhibited higher values for blends, compared with values of the pure polymers, which is an indication of good stability and tendency of gel formation.