Gelatin/Montmorillonite and Gelatin/Polyvinyl Alcohol/Montmorillonite Bionanocomposite Hydrogels: Microstructural, Swelling and Drying Properties

Gelatin/montmorillonite bionanocomposite hydrogels containing 0, 5 and 10 wt.% of montmorillonite were prepared via two different techniques, either a cooling or drying method. In addition, gelatin/polyvinyl alcohol/montmorillonite bionanocomposite hydrogels having gelatin/polyvinyl alcohol ratios of 1/1, 1/2 and 2/1, loaded with 0, 5 and 10 wt.% of montmorillonite, were prepared via a cyclic freezing-thawing technique. The microstructural properties of both types of the prepared bionanocomposite hydrogels were investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The gel fraction, swelling behavior and drying kinetics of all prepared bionanocomposite hydrogels were also studied. The XRD and SEM results showed a porous structure with a possible exfoliated morphology for both types of the prepared bionanocomposite hydrogels. In addition, the gel fraction of the bionanocomposite hydrogels increased and a more entangled and crosslinked network with a decreased pore size was obtained by increasing the loading level of montmorillonite for both types of the bionanocomposite hydrogels. The swelling ratio and drying rate of both types of the bionanocomposite hydrogels could be increased by decreasing the PVA portion or MMT loading level, while the swelling and drying ability of the gelatin/montmorillonite bionanocomposite hydrogels prepared via the cooling method was higher than those of the corresponding samples prepared via the drying method.