Characterization of Synthesized Sodium Carboxymethyl Cellulose with Variation of Solvent Mixture and Alkali Concentration

CMC is one of the water-soluble polysaccharide derivatives obtained from cellulose. Alkalization and carboxymethylation process will influence the quality of the CMC. The use of a combination of mixed solvents and varying alkali concentrations in the synthesis process of CMC needs to be studied so that CMC can be synthesized with the proper characteristics. This study was conducted to determine the characteristics of carboxymethyl cellulose synthesized using various solvents and NaOH concentrations. Carboxymethyl cellulose (CMC) was synthesized using solvent mixture, namely isopropanol: isobutanol (30: 70) and isopropanol:ethanol (50: 50) with varied concentration of NaOH of 5%, 10%, 15%, 20%, 25%, respectively. Synthesized CMC was characterized by an organoleptic test, pH, infrared analysis, and degree of substitution (DS). The result showed that characteristics of synthesized CMC were different from one another. The organoleptic test showed that synthesized CMC uses isopropanol: isobutanol (30: 70) was coarse powder, odourless and tasteless, ivory until burlywood along with increasing NaOH concentration; while the synthesized CMC with isopropanol: ethanol (50: 50) was a colourless, odourless, tasteless and fine powder. The pH of synthesized CMC was neutral. Infrared profile of synthesized CMC indicated the existence of carboxyl functional groups in 1600-1640 cm region. The degree of substitution value of formula II-5, II-10, II-15, II-20, II-25, IE-5, IE-10, IE-15, IE-20, and IE-25 were 0.885;0.757; 0.685; 0.592; 0.575; 0.611; 0.906; 0.603; 0.671; 0.751, respectively. Characteristics of CMC vary depending on the type of solvent mixture and NaOH concentrations used in synthesis. The more polarity of a solvent mixture the more colourless and higher DS value of synthesized CMC. On the other hand, the more alkali concentration in synthesis CMC the more colour and higher DS value was acquired.