Synthesis and characterization of sodium‐carboxymethylcellulose from cotton, powder, microcrystalline and nanocellulose

Abstract Cotton cellulose, powder cellulose, microcrystalline cellulose and nanocellulose were carboxymethylated with monochloroacetic acid by the suspension method in an ethyl alcohol medium. The effects of reaction conditions such as cellulose materials, sodium hydroxide concentration, molar NaOH/anhydroglucose unit ratio, monochloroacetic acid consumption, reaction temperature and etherification time on product quality, especially the degree of substitution, degree of polymerization and water solubility of sodium‐carboxymethylcellulose, were studied. By controlling these parameters, completely water‐soluble sodium‐carboxymethylcellulose samples with a high degree of substitution within 0.75, 1.47, 0.88, and 1.23 were obtained from cotton cellulose, powder cellulose, microcrystalline and nanocellulose. The boundaries of complete solubility of the obtained sodium‐carboxymethylcellulose were at low degrees of substitution (0.6, 0.44, 0.43, 0.33) and degrees of polymerization (880, 490, 240, 150) obtained from cotton cellulose, powder cellulose, microcrystalline cellulose and nanocellulose, respectively.