Regenerated cellulose
Also searched as: regenerated cellulosic, rayon, viscose, lyocell, modal
Cellulose dissolved and formed again as a manufactured textile fiber.
In detail
Regenerated cellulose fibers are manufactured by dissolving cellulose and forming it again as fiber. Viscose, modal and lyocell belong to this broader family, but their processes differ. Lenzing describes direct dissolution for lyocell and a chemical derivatization step before dissolution in its viscose route.
The science and numbers
Cellulose decomposes before it melts, because of its dense hydrogen-bonding network, so it must be dissolved and spun from solution; regeneration converts it largely from the native cellulose I crystal form to cellulose II. Three chemistries dominate. In viscose, pulp steeped in sodium hydroxide reacts with carbon disulfide to form cellulose xanthate, which dissolves in dilute alkali and regenerates in a sulfuric acid bath. In lyocell, pulp dissolves directly in aqueous N-methylmorpholine N-oxide and is spun across an air gap; Lenzing states that more than 99.8 percent of the solvent is recovered. Cupro uses Schweizer's reagent, a tetraamminecopper(II) hydroxide solution. Wet strength separates them: one comparison reports lyocell at about 32 cN/tex dry and 29 wet, while viscose loses close to half. Worker exposure to carbon disulfide is the viscose route's documented hazard; one Taiwanese study found ECG abnormalities in 25.9 percent of exposed workers against 2.7 percent of controls.
A practical example
The source of the cellulose and the name of the resulting fiber answer different questions. A wood or other plant feedstock does not mean the final fiber was mechanically extracted intact from that plant. Ask for both the generic fiber name and its feedstock information.
What to distinguish
Regenerated is not synonymous with recycled: the cellulose may originate from virgin or recovered inputs. A renewable feedstock also does not establish the environmental performance of the full production process.
Origins and history
In 1857 the Swiss chemist Matthias Eduard Schweizer found that cotton dissolves in a solution of copper salts in ammonia and can be regenerated from it. Louis-Henri Despeissis patented spinning fibers from such solutions in 1890, and by 1891 Max Fremery and Johann Urban were making filaments by this route near Aachen; Bemberg artificial silk followed from 1908. Direct-solvent lyocell came much later, brought to commercial scale by Courtaulds, and in 1996 the US Federal Trade Commission recognized lyocell as a subclass of rayon.
Related terms
Sources & further reading
- Lenzing: Fiber production technologies
- Lenzing: TENCEL Lyocell (producer page)
- Journal of Occupational and Environmental Medicine: Electrocardiographic abnormality for workers exposed to carbon disulfide at a viscose rayon plant (2006)
- FTC: FTC Approves 'Lyocell' for Use in Fabric Content Labeling (1996)
- Britannica: Cuprammonium rayon
Technical references reviewed 2026-09-22. Examples are illustrative. Industry organizations and manufacturers describe their own fields; their references are not independent product endorsements. Figures are approximate and depend on the stated test conditions.