Abstract
Carboxymethyl cellulose (CMC) forms a gel when mixed with acid as a result of replacement of sodium in carboxymethyl group with hydrogen; hydrogen bonds are formed among CMC molecules. CMC gel having new properties can be formed by mixing CMC with other materials. Konjac glucomannan (KM) is a water-soluble glucomannan with high molar mass and has high viscosity in low concentration aqueous solution. Previous study showed that CMC-KM-acid gel was stronger than CMC-acid gel, however, the strength depended on the molar mass of KM. When KM with high molar mass was mixed with CMC and acid, the gel was uniform, however, turbid at first glance, showing that compatibility of CMC and KM with high molar mass was not so good. However, when KM with low molar mass was mixed with CMC and acid, the gel was uniform and transparent, showing good compatibility of CMC and KM. Molar mass of KM showing good compatibility was less than 300 kDa. Scanning electron micrographs taken under moist condition clearly showed uneven and even surfaces for gels made using high molar mass and low molar mass KM, respectively. The compatibility of CMC and KM affected the mechanical properties of the CMC-KM-acid gels.
