Aqualon™ sodium carboxymethylcellulose
Aqualon sodium carboxymethylcellulose (CMC) is made by reacting sodium monochloroacetate with alkalicellulose under rigidly controlled conditions. The resultant anionic polymer is purified and dried. Purified CMC for personal care and cosmetic applications is typically sold at 99.5 percent minimum purity. In addition to thickening aqueous systems, CMC is used in personal care products for water binding, syneresis control and its ability to suspend pigments and active ingredients in solution. Aqualon CMC is an anionic, water-soluble polymer.
A variety of CMC grades are available, with varying degrees of substitution, viscosities and particle sizes. S-types provide smooth solutions, based on uniform substitution. O-types provide solubility and viscosity stability on storage in low pH media. Aqualon CMC grades designated P or PH are compliant with the monograph requirements of the National Formulary.
Ashland provides cellulose gum under the trade names Aqualon, Blanose™ and Bondwell™ depending on the region in which we serve you.
CMC is a cellulose ether, produced by reacting alkali cellulose with sodium monochloroacetate under rigidly controlled conditions.
The top figure shows the structure of the cellulose molecule; it is visualized as a polymer chain composed of repeating cellobiose units (in brackets). These, in turn, are composed of two anhydroglucose units (ß-glucopyranose residues). In this structure, n is the number of anhydroglucose units (which are joined through 1,4 glucosidic linkages), or the degree of polymerization, of cellulose.
Each anhydroglucose unit contains three hydroxyl groups. By substituting carboxymethyl groups for some of the hydrogens of these hydroxyls, as shown in bottom figure, sodium carboxymethylcellulose is obtained. The average number of hydroxyl groups substituted per anhydroglucose unit is known as the degree of substitution, or DS. If all three hydroxyls are replaced, the maximum theoretical DS of 3.0 (impossible in practice) results.