Morphological and Swelling Potential Evaluation of Moringa oleifera Gum/Poly(vinyl alcohol) Hydrogels as a...

Synergistic use of superabsorbent hydrogels has vital contribution to the daily life. This work gives an account of a facile approach to synthesize superabsorbent hydrogels based on Moringa oleifera gum and polyvinyl alcohol cross-linked with borax. Fourier transform infrared, X-ray diffraction, and scanning electron microscopy were employed to characterize the structure, crystallinity, and surface morphologies of the samples. The cross-link density, swelling ratio, reswelling, water retention properties, and salt sensitivity of hydrogels were investigated. Reaction parameters for the hydrogel synthesis were optimized on the basis of water absorbency, and the reaction condition of greater water absorbency after 12 h at room temperature was taken as an ideal condition. Optimum conditions were obtained as [poly(vinyl alcohol) PVA] = 10% (w/v) and [borax] = 1.05 × 10^-3 mol/L. Under the optimized conditions, the maximum swelling ratio of MOG/PVA hydrogel reached 1163 g/g in deionized water and 290 g/g in 0.9 wt % NaCl solution. Furthermore, all hydrogels exhibited salt sensitivity and excellent water retention capacity under the high temperature state and displayed smart swelling behaviors in physiological saline solutions. The water absorbency, reusability, and salt sensitivity of the hydrogels give these smart polymer wide promising applications.