Viscose Rayon, Sulphur

Carbon di.sulphide, CSg, is a volatile liquid (b.p. 46°), highly refractive, insoluble in water but soluble in ethyl alcohol and ether. It is made by the action of sulphur vapour on electrically heated coke. Its main uses are as a solvent and in the manufacture of CCI4 (p. 290), thiocarbanilide and viscose rayon ... 

Coagulation of xanthate is performed in 10% aqueous sulphuric acid. The xanthic acid derivative that is formed is not stable and is decomposed, and cellulose is regenerated. Viscose rayon fibres and cellophane films have been produced by this method. 

In addition to several empirical methods involving the evaluation of the a-cellulose content or the copper number of cellulose, there are methods such as the determination of furfural, mentioned in Chapter VI. Interest was also paid to the determination of sulphur in viscose rayon. 

Artificial fibres are as much in common use as the plastics and have equally interesting histories, as documented in Jenkins (2003). One of the first artificial fibres was rayon, the starting point for which is cellulose from wood pulp. It was first discovered in 1855 and was commercially produced by 1924 in the USA. Rayon is produced in two stages. First, cellulose is mixed with sodium hydroxide and carbon disulphide to produce viscose which, as its name suggests, is a thick, sticky liquid. As in the case of Terylene, the viscose is then forced through fine holes in a cylinder (a spinneret) as a jet and into dilute sulphuric acid to produce rayon. This is a fine, almost silky thread with multiple uses which include textiles, tyres and carpets. 

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