Gellan Gum-O,O'-Bis(2-Aminopropyl)-Polyethylene Glycol Hydrogel For Controlled Fertilizer Release

A gellan gum-Jeffamine superabsorbent hydrogel was obtained with different crosslink densities using different amounts of (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride) and N-hydroxysuccinimide. Infrared spectroscopy and thermal analysis confirm the crosslinking. A morphology analysis indicates denser structures for samples with higher crosslinking points. The swelling degree in high-acyl gellan gum hydrogels was equivalent to 145 times their dry weight, and 77 times when low-acyl gellan gum was used. Hydrogels also showed a 450 min water retention, as opposed to 280 min for pure water, evidencing good humidity control, suitable for use in arid climates. They also demonstrated a maximum release of commercial fertilizer of about 400 mg per gram for KH2PO4 and about 300mg per gram for NPK 20-5-20. (C) 2017 Wiley Periodicals, Inc.