Synthesis of chitosan-polyethylene glycol-based superabsorbent for enhanced water retention in agriculture

The basic aim of this study was to develop and optimize a synthesis method for producing superabsorbent based on chitosan/polyethylene glycol (Cs-PEG) blend with improved water retention properties. The Cs-PEG blend was prepared with different Cs-to-PEG blending ratio, the swelling at neutral (pH 7), basic (pH 9), and acidic (pH 5) was studied and Cs-PEG 0.06 exhibiting the best performance. The synthesized superabsorbent was studied through SEM, FTIR and XRD. SEM confirmed hierarchical surface characteristics from smooth homogeneity to granular porosity with enhanced water retention, making the Cs-PEG film ideal for applications as seed coating and soil conditioning. XRD showed a sharp diffraction peak at 20.06° with (020) plane, corresponding to the semi-crystalline structure of chitosan’s carbon skeleton. In Cs-PEG films, the intensity of this peak is significantly reduced, that helped in improved water absorption and retention. Moreover, the efficacy of Cs/PEG superabsorbent polymer blends were accessed in agricultural applications, including biodegradability in soil, moisture retention and their impact on crop growth parameters. The plant growth study indicated that seed germination, root length, and shoot length were significantly enhanced in Cs-PEG 0.06. This study provided an optimal balance between hydrophilicity, structural integrity, and biodegradability, making it a promising superabsorbent material for agricultural applications.