Rayon Emily L. & Meaghan O.

Introduction Rayon is technically neither an artificial fibre or a natural fibre. It is derived from cellulose which is a natural product but it requires a lot of processing to become Rayon.

Viscose Process The vast majority of rayon is fabricated using the viscose process. This process started in the early 1900’s.

Step 1: Cellulose; The purified cellulose that is used in the fabrication of rayon comes from processed wood pulp that is of a higher grade that that used for paper. Also known as “dissolving cellulose” or “dissolving pulp”. It is composed of long chain molecules. Step 2: Steeping; The sheets of cellulose are saturated in sodium hydroxide and left to set so that the sodium hydroxide can penetrate the sheets and transform it into “soda cellulose”. Step 3: Pressing; The soda cellulose is wrung out to remove the excess sodium hydroxide. Step 4: Shredding; The sheets of cellulose are shredded so they can be processed easier. Shredded cellulose is commonly referred to as “white crumb”. Step 5: Aging; Because white crumb has such a high alkalinity, so it is oxidized to lower molecular weights. Step 6: Xanthation; the cellulose crumbs are allowed to react with carbon disulphide to form cellulose xanthate. Step 7: Dissolving; The yellow crumb is disolved in an aqueous solution.

Step 8: Ripening; The viscose is allowed to stand for a period of time. Step 9: Flitering; It’s filtered to remove any undesolved materials that could cause defects. Step 10: Degassing; Bubbles of air that could also cause defects are removed. Step 11: Spinning; the material is moved into a bath containing; sodium sulphate, sulphuric acid and zinc sulphate. This causes the rayon filaments to bond together tightly. Step 12: Drawing; the newly bonded rayon filaments are stretched. Step 13: Washing; the rayon gets washed to remove any impurities that may remain. Step 14: Cutting; to be made usable the rayon is passed through a rotary cutter to create a fibre that can be processed the same as any other.

Properties High lustre, easily made to look like several types of fabric. (cheaper version of those fabrics) Highly absorbent. Does not insulate body heat. Not very durable. The original type of rayon was dry-clean only. It has a low elastic recovery (does not reclaim its original shape easily)

Pros Cheap Easily dyed Versatile Can be woven or knit Biodegradable Breathable Easily dyed Biodegradable Soft

Cons The production method releases harmful chemicals into the environment. The fabric yellows with age. There are cheaper fabrics (i.e. nylon) Some people are allergic.

Bibliography "Making Rayon Fiber." Mindfully.org | Mindfully Green. Web. 9 June 2010. <http://www.mindfully.org/Plastic/Cellulose/Rayon-Fiber.htm>. "Rayon Fiber - Rayon Staple Fiber, Rayon Textile Filament Fiber, Rayon Industrial Filament Fiber." FiberSource: The Manufactured Fiber Industry. Web. 10 June 2010. <http://www.fibersource.com/f-tutor/rayon.htm>. "What Is Rayon?" WiseGEEK: Clear Answers for Common Questions. Web. 10 June 2010. <http://www.wisegeek.com/what-is-rayon.htm>.