Chapter 6

Chapter 6 - Chapter 6 Manufactured Cellulosic Fibers:...

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Chapter 6 – Manufactured Cellulosic Fibers: Rayon: 1 st regenerated fiber (regenerated cellulose) a manufactured fiber composed of regenerated cellulose unmodified cellulosic fiber “artificial silk” First produced in US First manufactured fiber Unmodified cellulosic fibers viscose rayon regular rayon high-wet-modulus Rayon (HWM) high-tenacity rayon Cuprammonium rayon Lyocell Modified cellulosic fibers acetate triacetate Viscose Rayon: wood pulp (major source) cotton fibers – linters bamboo (goes through the same processes as viscose rayon) Viscose Rayon Processing:
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timber harvested eucalyptus tree spruce tree southern pine chips treated dissolving pulp 95% cellulose pressed into blotter-like sheets (95% cellulosic) Manufacturing Steps of Viscose Rayon: 1. slurrying ( steeping ) soaked in sodium hydroxide (soak blotter-like sheets) swells polymer chains (easier to break and dissolve – prepares for step 2) alkali cellulose shredded into “white crumbs” (shred those sheets) 2. Ageing polymer chains broken easier to dissolve 3. xanthation carbon disulfide polymers pushed apart 4. in sodium hydroxide
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viscous like honey 5. filtration insoluble particles removed delustering agent, pigment added PLACE TO PUT ADDITIVES 6. extrusion wet spun dilute sulfuric acid bath *RAYON HAS SO MANY STEPS WITH CHEMICALS – IT IS NOT “GREEN” TO MAKE – ILLEGAL TO MAKE IN U.S. – NOW PRODUCED IN ASIA* Modifications: high-wet-modulus rayon (HWM) modal , polynosic rayon = HWM Better than regular Rayon resistance to deformation when wet
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This note was uploaded on 01/19/2012 for the course HUEC 2040 taught by Professor Staff during the Fall '08 term at LSU.

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Chapter 6 - Chapter 6 Manufactured Cellulosic Fibers:...

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