Carboxymethyl Cellulose Properties Supporting Thickening and Stability
Carboxymethyl Cellulose (CMC) is a versatile, water-soluble anionic polymer derived from cellulose, the most abundant natural polymer on Earth. It is produced through a chemical reaction known as etherification, where cellulose from wood pulp or cotton linters is treated with sodium hydroxide and monochloroacetic acid. This process substitutes hydroxyl groups on the cellulose chain with carboxymethyl (-CH₂-COOH) groups, converting the insoluble cellulose into its water-soluble sodium salt. The degree of substitution (DS)—the average number of carboxymethyl groups per glucose unit—determines key properties like solubility, viscosity, and stability. This chemical modification creates a long-chain molecule that can thicken solutions, bind water, form films, and stabilize emulsions and suspensions.