Synthesis of hydrogel film based on carrageenan extracted from Kappaphycus alvarezii

Abstract

Hydrogel based on kappa carrageenan extracted from Kappaphycus alvarezii was synthesized by film immersion in glutaraldehyde solution (GA 4% w/w) as crosslinker for 2 min and then followed by thermal curing at 110 °C for 25 min. The obtained crosslinked films were washed using ethanol to remove the unreacted crosslinker and finally dried to constant weight. The aim of this research was to investigate the effect of carrageenan recovery method on the prepared hydrogel properties. The method of carrageenan extraction strongly determined the swelling properties of crosslinked carrageenan. Hydrogel obtained from alkali treated carrageenan showed higher swelling ability compared to hydrogel from nonalkali treated carrageenan. Hydrogel from alkali treated carrageenan showed the ability of sensitive to pH media. Swelling degree of alkali treated carrageenan based hydrogels increased by increasing pH solution from about 5 g/g for neutral pH to 20 g/g for pH~13.