Fabrication and characterization of Chitosan/Poly (vinyl alcohol)-co-(vinyl acetate)-co-(itaconic acid) hydrogel membranes

A pH sensitive hydrogel was developed by freeze thaw method based on chitosan and Poly (vinyl alcohol)-co-(vinyl acetate)-co-(itaconic acid) (PVACO). The hydrogel membranes were characterized by FTIR (Fourier transform infrared) spectroscopy, X ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The mechanical properties of the blend membranes were evaluated by tensile strength test. FTIR spectral characterization showed probable molecular interactions between the natural and synthetic polymer. The swelling investigation indicated that hydrogels were highly sensitive to pH of the surrounding environment. The swelling ratios of the gels in stimulated gastric fluid (SGF, pH 1.4) were higher than those in stimulated intestinal fluids (SIF, pH 7.4). The SEManalysis of the freeze dried hydrogels reveals highly porous morphology of blend hydrogels with uniformly arranged pores of 20-100 mu m size and it was found that porosity eventually increases with increasing ratio of chitosan in the prepared hydrogels. Mechanical properties were found to be sufficient in all the developed membranes.