Preparation of starch-graft-acrylic acid/bentonite composite gel

A hydrogel is a hydrophilic polymer with a three-dimensional network that can retain a large amount of water and have swelling behaviour without dissolving in water. A hydrogel can be applied in various fields. Some are for Enhanced Oil Recovery (EOR), water harvesting, and diapers. Regarding its application, the hydrogel needs to have a high water absorption capacity. This research is aimed to prepare hydrogel that has a high absorption capacity by modifying the structure of the polymer, which was done by modifying the crosslinker. The hydrogel was prepared by grafting partially neutralised acrylic acid onto gelatinised starch in a reactor using potassium persulfate as an initiator with the temperature of 60 °C. Then, it was added by N,N'-methylene-bis-acrylamide (MBA) as a crosslinker to create three-dimensional networks. This hydrogel was characterised by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and water absorbency. The result demonstrated that the highest absorption of water with variable concentration of crosslinker was 512.12 g/g.