[3] The polar (organic acid) carboxyl groups render the cellulose soluble and chemically reactive.

[citation needed] An additional purification process is used to remove salts to produce pure CMC, which is used for food and pharmaceutical applications.

[6] An intermediate "semi-purified" grade is also produced, which is typically used in paper applications such as the restoration of archival documents.

The functional properties of CMC depend on the degree of substitution of the cellulose structure (i.e., how many of the hydroxyl groups have been converted to carboxymethylene groups in the substitution reaction), as well as the chain length of the cellulose backbone structure and the degree of clustering of the carboxymethyl substituents.

It is used primarily because it has high viscosity, is nontoxic, and is generally considered to be hypoallergenic, as the major source fiber is either softwood pulp or cotton linter.

It is used for a viscosity modifier or thickener and to stabilize emulsions in various products, including ice cream, mayonnaise, and beverages.

CMC molecules, negatively charged at wine pH, interact with the electropositive surface of the crystals, where potassium ions are accumulated.

[18][17][full citation needed] CMC is a common ingredient in cleaning products because of its thickening and stabilizing properties and nontoxic composition.

Additionally, CMC serves as a binding agent in non-woven fabrics, contributing to the strength and stability of the material.

The use of CMC in candy preparation ensures smooth dispersion in flavor oils and improves texture and quality.

[9][12][25][26] Some examples include: In ophthalmology, CMC is used as a lubricating agent in artificial tears solutions for the treatment of dry eyes.

[30] In veterinary medicine, CMC is used in abdominal surgeries in large animals, particularly horses, to prevent the formation of bowel adhesions.

[31] Insoluble CMC (water-insoluble) can be used in the purification of proteins, particularly in the form of charged filtration membranes or as granules in cation-exchange resins for ion-exchange chromatography.

[35] Moreover, CMC has been used extensively to characterize enzyme activity from endoglucanases (part of the cellulase complex); it is a highly specific substrate for endo-acting cellulases, as its structure has been engineered to decrystallize cellulose and create amorphous sites that are ideal for endoglucanase action.

[citation needed] CMC is desirable because the catalysis product (glucose) is easily measured using a reducing sugar assay, such as 3,5-dinitrosalicylic acid.

[citation needed] CMC is often used in conjunction with styrene-butadiene rubber (SBR) for electrodes requiring extra flexibility, e.g. for use with silicon-containing anodes.

[citation needed] Effects on inflammation, microbiota-related metabolic syndrome, and colitis are a subject of research.

[40][41][non-primary source needed] While thought to be uncommon, case reports of severe reactions to CMC exist.