Synthesis and swelling characterization of nata-de-coco-andwater-hyacinth-based hydrogel

Abstract

Hydrogel is one type of polymers that is able to absorb and retain water in huge amount in its body. A parameter of performance of hydrogel is swelling ratio. In this research, we used water hyacinth and nata de coco. Cellulose in both materials was isolated until powdered cellulose was achieved. Next, both types of cellulose were converted into carboxymethylcellulose (CMC) and then into hydrogel using citric acid as cross linker in aqueous solution. Concentration of citric acid was varied into 3 variations, 10%, 15%, 20% (w/w CMC). Each hydrogel formed was assessed in terms of performance, existence of functional group and morphology. Swelling ratio assessment was conducted per hour, which is swelling ratio at the 1st, 2nd, 3rd and 24th hour. The result of FTIR showed that cellulose, CMC and hydrogel were successfully formed. Swelling ratio assessment showed that at concentration of 10% and 15%, the hydrogel showed huge swelling ratio but very poor gel fraction and stability. At concentration of 20%, hydrogel found stable and had swelling ratio of 2291% for nata de coco and 1862% for water hyacinth. Finally, for hybrid hydrogel at concentration of 20% citric acid and ratio of mixing between nata de coco CMC and water hyacinth CMC was 50:50, hydrogel formed shows good strength and stability, but with decreasing swelling ratio which was 1171%.