Rayon

Rayon, artificial textile material, composed of cellulose obtained from the pulp of trees such as spruce. Since the introduction of rayon about 1900, it has been used in many textile fields. At first rayon was called artificial silk because, in its filament form, it resembles silk; however, the chemical composition of rayon is entirely different from that of silk.

Rayon can be made by either the viscose process or the cuprammonium process. In the viscose process purified cellulose is treated with sodium hydroxide, then with carbon disulphide, to form a viscous yellow liquid called viscose. In the cuprammonium process purified cellulose is treated with cuprammonium liquor, then with sodium hydroxide, to form viscose. The manufacture of rayon filaments—and all manufactured fibres—is done by means of an extrusion process called spinning. In this procedure the fibre-forming liquid is forced through tiny holes in a nozzle or spinneret into a liquid bath containing chemicals that produce filaments of pure cellulose, which can be spun into yarn. The filaments are drawn together to form both fibres and yarn in a single, continuous process.