What is viscose?

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Viscose or more commonly known as Rayon,  was made  to substitute for the more expensive silk fiber. Though rayon is considered to be synthetic it is made from tree cellulose. It was first manufactured by an American Company named, Avtex Fibers Inc in 1910. There are different kinds of rayons, and most of them are highly absorbent, easy to dye, soft on the skin  and became very popular when it was first produced.

 

How is Rayon processed?

  • Viscose is manufactured by treating purified cellulose in caustic soda solution  to form a salt of soda cellulose.
  • It is pressed to remove excess caustic soda  
  • the soda cellulose is then squeezed and shredded to increase the surface area so as to make it more pliable to processing. This is also known as white crumbs.
  • The white crumb is then exposed under controlled conditions to oxygen so as to oxidize it. This involves careful monitoring so that the length of the fibers is short enough to manage the viscosity of the solution but long enough to  produce good fibers.
  • The  soda cellulose aged fiber is then treated with carbon disulphide, CS2. This results in formation of xanthate esters plus some inorganic impurities which gives the fibers a yellow color and from her eon called as yellow crumb.
  • Yellow crumb is again dissolved in aqueous caustic soda to form a highly viscose liquid and so the name is called viscose process.
  • After ripening and filtering, degassing is done to remove any air bubbles in the fabric,
  • stretching is done to draw it into filaments and textile fabrics.
  • It is washed using several techniques
  • After this it is pretty much processed like cotton.

 

Applications of viscose

Viscose is soft, absorbent and feels comfortable when worn on the skin. Viscose is used in the preparation of shirts, trousers, diapers, napkins, towels and many other products. Viscous fiber material is present in many home products. Viscose material is softer than cotton and more springy than silk. Viscose is comfortable to wear and it can be used for dying as well. There are two types of fibers namely natural and artificial. Natural fibers are cotton, wool and silk and artificial are synthesized with petrochemicals like nylon and polyester.

 

Viscose comes under both of them as the raw material used for viscose is cellulose which is broken down and forms fibers. Cotton consists of 90% cellulose, so viscose is considered a natural fiber. Viscose is used in making cellophane. Cellophanes are often used in wrapping gifts and food items etc. To prepare the cellophanes it undergoes a special process during which the wood cellulose is mixed with sodium hydroxide and carbon disulphide.  Viscose is not expensive and used as a cheaper alternative to silk. Manufacturing of Viscose  has created a  lot of pollution due to carbon disulfide used in the preparation of viscose and so, this has resulted the reduction in the usage of viscose. Moreover with modern technology much richer fabrics have been created thus diminishing its use.