rayon

thumb|Rayon is made by dissolving cellulose and then precipitating it into a fiber. One method is shown here using a blue solution of cellulose (Schweizer's reagent|cuprammonium hydroxide used to dissolve) and colorless sulfuric acid to precipitate. The blue color fades from the fiber over time.

Rayon, also called viscose, is a semi-synthetic fiber made from natural sources of regenerated cellulose, such as wood and related agricultural products. It has the same molecular structure as cellulose. Many types and grades of rayon fibers and films exist. Some imitate the feel and texture of natural fibers such as silk, wool, cotton, and linen. It can be woven or knitted to make textiles for clothing and other purposes. Rayon production involves solubilizing cellulose fibers. Three common methods are as follows: The cuprammonium process (obsolete), using ammoniacal solutions of copper salts The viscose process (most common) using alkali and carbon disulfide The Lyocell process, using amine oxide, avoids neurotoxic carbon disulfide but is more expensive