REGENERATED FIBRES

VISCOSE

Viscose rayon
• Viscose was the first man-made fibre to be produced
• It was first introduced in 1905

• It is manufactured from wood pulp cellulose
• As it cannot be dissolved in it's original form, the polymer is first chemically altered
• It is then dissolved in a sodium hydroxide solution
• The liquid polymer is regenerated by extrusion into a dilute sulphuric acid solution (wet-extrusion)
• The resulting filament is called Viscose

• Using this basic process a range of viscose fibres with different charactoristics can be produced
• These charactoristics could include, additional strength, texture or addition of a high moisture absorbancy factor

• Viscose fibres are chemically similar to those of cotton
• Viscose fibres are fairly weak and best when blended with other fibres

MODIFIED FIBRES

THE RAYONS

Diacetate rayon
• The cellulose polymer is reacted with water
• Then the polymer is dissolved in acetone
• The solution is extruded into hot air using the solvent-dry process
• The solvent evaporates leaving the polymer in the fibrous form

• Acetate rayon fibre is spun to produce a fabric that is soft to the touch and drapes like silk
• A common brand name is Dicel

Triacetate rayon
• Triacitate rayon is similar to Diacetate but needs a different solvent
• The polymer is reacted with acetic anhydride in acetic acid
• It is then dissolved in dichloromethane before being extruded in the same way as diacetate

• The Triacetate filament is not absorbent, and does not shrink or stretch
• It is usually blended with other fibres for use in knitting yarns
• The two common brand names are Tricel and Arnel

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