Rayon

By: Alex Hammer and Kelsey Lee

Rayon is a synthetic fiber made from reoccurring monomers. In the textile industry, rayon is also referred to as viscose rayon and artificial silk. Rayon is made from cellulose from wood pulp. Cellulose is a fiber that is both biodegradable and recyclable. Cellulose from wood pulp, NaOH, Carbon Sulfide, and CS2H2SO4 combine to form silk like strands that are rayon.

Steps to Making Rayon


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Rayon is the oldest manmade commercial fiber. The process of making viscose was discovered in 1891 by C.F. Cross and E.J. Bevan. There is a wide variety of rayons due to its versatility because it is chemically engineered. There are three different ways of producing rayon fibers: viscose rayon, cuprammonium rayon and saponified cellulose acetate. Of all the methods, viscose is the least expensive and used most often. Cellulose pulp is transformed into viscose rayon through the following steps:
1. Steeping, 2. Pressing, 3. Shredding, 4. Aging, 5. Xanthation, 6. Dissolving, 7. Ripening, 8. Filtering, 9. Degassing, 10. Spinning 11. Drawing, 12. Washing, 13. Cutting



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The above picture is NaOH and CS2 added to Cellulose to form Viscose. Viscose then passes through a spinneret into dilute H2SO4 (a dehydration aid) to form rayon. Monomers of Rayon are linked by dehydration.

Although Rayon is not originally cross-linked, it has cross-linking capabilities. When formaldehyde is added to Rayon, it becomes cross-linked. By crosslinking, rayon becomes durable and does not shrink as much. When cellulose fibers react with acid aldehydes, crosslinked fibers are formed. These fibers, which make up rayon, have improved centrifuge retention capacity, fluid acquisition rate, resiliency, absorbent capacity, absorbency under load, and other absorbent properties.


Practical and Industrial Uses of Rayon
1. apparel (ex. blouses, dresses, jackets, slacks, sports wear, suits, ties, lingerie, linings, scarves, and Hawaiian shirts)
2. furnishing (ex. bed spreads, blankets, curtains, sheets, table clothes, upholstery, slipcovers)
3. industrial uses (ex. industrial products, nonwoven products, tire cord)
4. other uses (ex. feminine hygiene products, yarn)
5. medical and pharmiceutical industries (ex. medical surgical products, bandages, bottles, bags)
6. Rayon mixed with wool and other fibers to form carpets

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100% rayon skirt
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rayon fabric swatches
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100% Rayon yarn
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Rayon Skirt


Physical and Chemical Characteristics
Physical:
1. highly absorbent
2. soft
3. comfortable
4. easy to dye
5. drapes well

Chemical:
1. burns quickly
2. gives off odor when burning
3. blends easily with other fibers
4. hot dilute acids impact rayon
5. high concentration bleaches impact rayon
6. mildue under severe hot and moist rayon impact rayon
7. prolonged exposure to sunlight causes weakening of the rayon because of degradation of cellulose chains

In order to meet a variety of different uses, rayon is engineered to possess different properties. There are many different types of rayon. Some of them include:
1. High Wet Modulus Rayon
2. Polynosic Rayon
3. Flame Retardant Fibers
4. Super Absorbant Rayon
5. Micro Denier Fibers
6. Cross Section Modification
7. Tencel Rayon
8. Lyocell


Works Cited

Chemically cross-linked cellulosic fiber and method of making same. Free Patents Online. 14 May 2008.
<http://www.freepatentsonline.com/7094318.html>

Early Synthetic Polymers. 2003. Polymer Science Learning Center and University of Southern Mississippi. 14 May 2008. <http://pslc.ws/macrog/kidsmac/early.htm>

Knitting in Hollywood. WordPress. 14 May 2008. <www.knittinginhollywood.org>

Lakewood Conferences. Bill Communications Minneapolis. 14 May 2008. <www.lakewoodconferences.com>

Made-In-China.com. 14 May 2008. <www.made-in-china.com>

Man Made Organic Materials. Brodhead Garrett/Frey Resources. 14 May 2008. <http://home.att.net/~cat6a/org_mat-I.htm>

Rayon. 30 April 2008. Wikipedia-the free encyclopedia. 14 May 2008.<http://en.wikipedia.org/wiki/Rayon>

Rayon. Tripod.com. 14 May 2008. <http://wackyanne.tripod.com/studio/rayon.htm>

Rayon Fiber. Fiber Source. 14 May 2008. <http://www.fibersource.com/f-tutor/rayon.htm>

Rayon Fibers. April 2004. 14 May 2008. <http://www.engr.utk.edu/mse/Textiles/Rayon%20fibers.htm>

Rayon-- The Multi-Facetted Fiber. Ohio State University Online. 14 May 2008. <http://ohioline.osu.edu/hyg-fact/5000/5538.html>

Microbial Cellulose. Malcolm Brown. 16 May 2008. <http://www.ask.com/bar?q=Is+rayon+biodegradable%2C+recyclable+or+renewable&page=1&qsrc=0&ab=0&u=http%3A%2F%2Fwww.botany.utexas.edu%2Ffacstaff%2Ffacpages%2Fmbrown%2Fposition1.htm>