SYNTHESIS AND CHARACTERIZATION OF HYDROGEL FROM CELLULOSE DERIVATIVES OF WATER HYACINTH (Eichhornia crassipes) THROUGH CHEMICAL CROSS-LINKING METHOD BY USING CITRIC ACID

Hydrogels are defined as a three-dimensional polymer structures that can be formed from natural or synthetic polymers and are able to retain large amounts of water. Hydrogels can be made in two ways, i.e. physical cross-linking and chemical cross-linking. The stable structure and effective swelling of the hydrogel can be obtained through the chemical cross-linking process. In this study, hydrogel was made by natural polymer that is non-toxic. Hydrogels were synthesized by using cellulose or its derivatives (Carboxymethyl Cellulose (CMC)) through chemical crosslinking process with citric acid as crosslinking agent. Cellulose is derived from water hyacinth plant, as one of the potential sources of cellulosic fibres in producing of CMC. Various conditions of preparation, such as citric acid concentration and variations in the value of the degree of substitution of NaCMC, were observed through the hydrogel characterization results. Variations of variables in this research consist of the concentration of citric acid of 5, 10, and 15% and the ratio of composition isobutyl-isopropyl alcohol solvent in order to get the value of degree of substitution of CMC. Based on the results, the hydrogel with the highest swelling ratio is when the composition of isobutyl-isopropyl alcohol is 2: 8 and the concentration of citric acid is 10%.