rayon

Rayon is a man-made fiber, a semi-synthetic material composed of regenerated cellulose derived from natural sources such as wood pulp or cotton linters. Although produced by chemical processing, rayon originates from cellulose found in plants and is not considered a purely synthetic polymer like polyester.

Most widely used varieties are viscose rayon, produced by dissolving cellulose in caustic soda and carbon disulfide to form a viscous solution that is regenerated into fibers by spinning. A newer process, lyocell, uses an amine oxide solvent in a closed loop to dissolve cellulose and spin fibers, often marketed separately. Other rayon types include modal, a high-tenacity form mostly from beech tree pulp, and cupro, produced from copper ammonium rayon.

Rayon fibers exhibit excellent comfort, high moisture absorption, and good drape, but can be weaker when wet and are prone to shrinking and wrinkling. They take dye readily and are used in clothing such as dresses and linings, as well as upholstery, medical textiles, and industrial applications.

Historically, rayon emerged in the late 19th century as a cellulose-based alternative to silk. The viscose process involves hazardous chemicals; early production used carbon disulfide, raising health concerns. Modern processes have reduced emissions, especially with lyocell's closed-loop solvent recovery, but rayon production remains more chemically intensive than cotton or wool. Rayon is generally considered biodegradable.

While rayon is derived from natural cellulose, it is classified as a semi-synthetic fiber because it requires substantial chemical processing.