RAYON Usage And Synthesis

Uses

Rayon, the first commercial manmade fiber, is composed of cellulose in a quite pure form. It is produced by the treatment of wood pulp with alkali and carbon disulfide to form a viscous solution of cellulose xanthate. This viscous solution, called viscose, is extruded through spinnerets into an aqueous acid bath that coagulates the cellulose xanthate, decomposes it, and regenerates the cellulose.
Rayon fibers are easily wetted by water and provide easy access to dye molecules. Dyeing may take place by absorption or by reaction with the hydroxyl groups. Rayon fibers may also be dyed with mordant and vat dyes.

Uses

Nonwoven fabrics, surgical dressings, mechan- ical rubber goods, coated fabrics, felts and blankets, blends with cotton for home furnishings, etc.

Definition

Generic name for a semisynthetic fiber composed of regenerated cellulose as well as man- ufactured fibers composed of regenerated cellulose in which substituents have replaced not more than 15% of the hydrogen of the hydroxyl groups. Rayon was first made

Preparation

Viscose rayon is obtained by reacting the hydroxy groups of cellulose with car- bon disulfide in the presence of alkali to give xanthates. When this solution is poured (spun) into an acid medium, the reaction is reversed and the cellulose is regenerated (coagulated).

Definition

An artificial fiber formed from wood pulp (cellulose). There are two types. Viscose rayon is made by dissolving the cellulose in carbon disulfide and sodium hydroxide. The solution is forced through a fine nozzle into an acid bath, which regenerates the fibers. Acetate rayon is made by dissolving cellulose acetate in an organic solvent, and forcing the solution through a nozzle. The solvent is evaporated, and the cellulose acetate thus obtained as fibers.

Definition

rayon: textile made from cellulose.There are two types, both madefrom wood pulp. In the viscoseprocess, the pulp is dissolved in carbondisulphide and sodium hydroxideto give a thick brown liquidcontaining cellulose xanthate. Theliquid is then forced through finenozzles into acid, where the xanthateis decomposed and a cellulose filamentis produced. The product is viscoserayon. In the acetate process cellulose acetate is made and dissolvedin a solvent. The solution isforced through nozzles into air,where the solvent quickly evaporatesleaving a filament of acetate rayon.

Hazard

Flammable, not self-extinguishing, moder- ate fire risk.

Industrial uses

Rayon is a general name for artificial-silk textile fibers or yarns made from cellulose nitrate, cellulose acetate, or cellulose derivatives. In general, the name rayon is limited to the viscose, cuprammonium, and acetate fibers, or to fibers having a cellulose base. Other synthetic-fiber groups have their own group names, such as azlon for the protein fibers and nylon for the polymeric amine fibers, in addition to individual trade names.
Viscose rayon is made by treating the cellulose with caustic soda and then with carbon disulfide to form cellulose xanthate, which is dissolved in a weak caustic solution to form the viscose.
Rayons manufactured by the different processes vary both chemically and physically.