Synthesis of polyvinyl alcohol-based polymer hydrogel as water holding in sandy soil using gamma radiation technique and its application for urea loading

Abstract

Hydrogel loading urea has dual functions, namely retaining water and releasing urea in a controlled manner so it can be applied to sandy soil. This study aimed to examine the effect of different additives (CMC and chitosan) in preparing PVA-based hydrogels on the hydrogel properties and characteristics. In the hydrogel preparation, the PVA solution at various concentrations was mixed with chitosan and CMC solutions. The mixture was then irradiated using gamma rays to produce hydrogel. Then, the hydrogel was dried and crushed for analysis. The results showed that PVA/chitosan-based hydrogels had swelling of 7.75–25.16 g/g, water holding of 63.43–65.27 %, water retention of 22.45–26.81 % for 5 days, and urea loading of 76.50–81.43 %. Meanwhile, PVA/CMC-based hydrogels had swelling of 4.75–36.29 g/g, water holding of 63.92–65.74 %, water retention of 31.59–33.88 % for 5 days, and urea loading of 67.21–84.44 %. The PVA/CMC-based hydrogel had a lower crystallinity percentage and smoother surface morphology than the PVA/chitosan-based hydrogel.

Keywords

• Carboxymethyl cellulose
• Chitosan
• Hydrogel
• Irradiation
• Urea loading