viscose rayon (cotton modification)

Viscose Rayon

Presented By: Kazi Sazed Salman

ID No: 111-23-130

Rayon:Rayon is a manufactured regenerated cellulose fiber.

Type of rayon differs in manufacturing process and properties of the finished product.

The types of rayon:

Viscose Modal Lyocell

Viscose RayonViscose is a solution of cellulose xanthenes made by treating a cellulose compound with Sodium hydroxide (NaOH) & Carbon disulfide (CS2). The viscose solution is used to spin the fiber viscose rayon. It is soft man-made fiber commonly used in dresses, shirts, shorts, coats, jackets and other outer wear. It is also used as industrial yarns like tire cord, upholstery and carpets.

Chemical reaction for Viscose Rayon production The cellulose is treated with 17.5% solution of NaOH which converts it into Soda-cellulose.

cell-OH + NaOH => cell-ONa + H2O Soda-cellulose reacts with CS2 to form Na-

cellulose Xanthate.

cell-ONa + CS2 => cell-O-CS-SNa Na-cellulose Xanthate remains desolved in

a dilute solution of cauctic soda. It is extruded into H2SO4 which regenerates the cellulose. Then it forms in the long fillaments (Viscose Rayon).

cell-O-CS-SNa + H2SO4 => cell-OH + Na2SO4

Steps of Viscose Rayon manufacturing processPulp PreparationStipping &

PressingShreddingAgeing

ChurningMixing(Solution)

RipeningSpinning

Purification

Physical Properties of Viscose RayonMoisture

Absorption13% Tensile

StrengthDry:

1.5-2.4 g/dWet:

0.7-1.2 g/dElasticity 2-3% Elongation at

Break15-30%

Density 1.5 g/cc Specific Gravity

1.5

Melting Temperature

176-240* C Abrasion Resistance

Low

Dimensional Stability

High Flammability Burns like cotton

CHEMICAL Properties of VISCOSE RAYON

Acid: Hot acids may cause damage but have resistance among cold weak acids.

Alkali: Concentrated Alkalis cause swelling & reduce strength.

Solvent: Resistant to organic solvents

Bleach: Attacks by strong oxidizing bleaches.

Biological agents: Attacks by moulds & mildew.

Light: UV light may reduce the strength.

Dye ability: Better affinity with vat, direct & sulphure dye.

Comparison of different fibers

Types of Viscose Rayon

Regular RayonHigh Wet ModulusHigh Tenacity RayonCupramonium

RayonTrade names of Viscose Rayon

Zantral (USA)Avril (USA)Fibro HSO (USA)Grasim (India)

Viscose Rayon made Yarns & Fabrics

Thank YouWish you have enjoyed the presentation.