NaCMC

NaCMC, or sodium carboxymethyl cellulose, is the sodium salt of carboxymethyl cellulose, a water-soluble derivative of cellulose. The polymer consists of cellulose chains in which some hydroxyl groups are replaced by carboxymethyl groups, giving an anionic, high-molecular-weight polyelectrolyte. The degree of substitution (DS)—the average number of carboxymethyl groups per glucose unit—along with molecular weight, largely determines viscosity and gel-forming behavior.

Production and forms: NaCMC is produced by etherification of cellulose with monochloroacetic acid in an alkaline medium, typically using sodium hydroxide. The resulting product is manufactured in grades with varying DS and viscosity to suit different applications. It is soluble in cold water and can form viscous solutions, gels, or pastes depending on DS, concentration, and ionic strength.

Properties: NaCMC is a hydrophilic, anionic polymer capable of thickening and stabilizing diverse formulations. It exhibits shear-thinning (pseudoplastic) behavior, provides suspension stability, and can act as a binder or film-forming agent. The performance depends on DS, molecular weight, and the presence of salts or other additives. It is generally resistant to pH changes over a broad range and is stable under many common processing conditions.

Applications: In the food industry, NaCMC is used as a thickener, stabilizer, and binder in dairy, sauces, dressings, and baked goods. It is also employed in cosmetics and personal care products as a thickener and emulsifier stabilizer, in pharmaceuticals as a binder and suspending agent, and in oil and gas drilling fluids to control viscosity and fluid loss. Additional uses include paper, textiles, coatings, and other industrial formulations.

Regulatory status: NaCMC is widely regulated as a food additive (often referenced as carboxymethyl cellulose, E466) and is generally regarded as safe when used per good manufacturing practices. Safety considerations include potential digestive sensitivity in some individuals and product-specific allergen controls where relevant. See also Carboxymethyl cellulose.