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Rayon-The first man made fiber

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Abhilesh Patwal
Abhilesh Patwal

The presentation is about the rayon fiber for school going students. In it, I have covered its making process, chemical composition, things that can be made out of it and how good or bad it is for our environment.

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Rayon -the first man-made fibre. Name: Nikita Negi Class: 8th A Roll no.: 40
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.
Rayon Production: Wet spun rayon (viscose) High wet modulus (HWM) rayon Physical structure: Natural bright Can be solution dyed Regular rayon: Serrated cross section. HWM rayon: Rounder cross section and better performance.
Chemical Formula of Rayon
Viscose Process The vast majority of rayon is fabricated using the viscose process. This process started in the early 1900s.
Manufacturing Process Purification of 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. Steeping Process: 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. Shredding or cutting process: The sheets of cellulose are shredded so they can be processed easier. Shredded cellulose is commonly referred to as white crumb.
Ageing Process: Because white crumb has such a high alkalinity, so it is oxidized to lower molecular weights. Churning Process or Xanthation: The cellulose crumbs are allowed to react with carbon disulphide to form cellulose xanthate. Mixing or dissolving Process: The yellow crumb is dissolved in an aqueous solution. Ripening Process: The viscose is allowed to stand for a period of time. Filtering: Its filtered to remove any undissolved materials that could cause defects.
Degassing: Bubbles of air that could also cause defects are removed. Spinning Process: The material is moved into a bath containing; sodium sulphate, sulphuric acid and zinc sulphate. This causes the rayon filaments to bond together tightly. Drawing: The newly bonded rayon filaments are stretched. Washing: The rayon gets washed to remove any impurities that may remain. 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.
Rayon-The first man made fiber
Rayon Properties Physical: Fluid drape, soft hand, control lustre, length, diameter. Mechanical: Regular: Weak, especially wet. HWM: Stronger, adequate breaking elongation. Chemical: Absorbent, dyes well, high regain, smooth, soft, good heat & static conductor. Appearance retention: Moderate Regular: poor resiliency, progressive shrinkage HWM: less wrinkling, accepts durable press & dimensional stability finishes, can be mercerized Care: Regular: limited wash ability (wrinkling, loss of sizing, excessive shrinkage) dry clean HWM: greater wash ability, less wrinkling, shrinkage may be controlled
Environmental Impacts of Fabric: Rayon Rayon requires raw wood, usually hemlock or pine, and a great deal of water and energy to process. Here's a fun fact: Port Angeles, WA was once home to a pulp mill that produced the raw cellulose needed to make rayon and a number of other products. Today, it's a toxic clean-up site. The company's name? Rayonier. This is another artificial fibre, made from wood pulp, which on the face of it seems more sustainable. However, old growth forest is often cleared and/or subsistence farmers are displaced to make way for pulpwood plantations. Often the tree planted is eucalyptus, which draws up phenomenal amounts of water, causing problems in sensitive regions. To make rayon, the wood pulp is treated with hazardous chemicals such as caustic soda and sulphuric acid.
Rayon-The first man made fiber

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Rayon-The first man made fiber

  • 1. Rayon -the first man-made fibre. Name: Nikita Negi Class: 8th A Roll no.: 40
  • 2. 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.
  • 3. Rayon Production: Wet spun rayon (viscose) High wet modulus (HWM) rayon Physical structure: Natural bright Can be solution dyed Regular rayon: Serrated cross section. HWM rayon: Rounder cross section and better performance.
  • 5. Viscose Process The vast majority of rayon is fabricated using the viscose process. This process started in the early 1900s.
  • 6. Manufacturing Process Purification of 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. Steeping Process: 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. Shredding or cutting process: The sheets of cellulose are shredded so they can be processed easier. Shredded cellulose is commonly referred to as white crumb.
  • 7. Ageing Process: Because white crumb has such a high alkalinity, so it is oxidized to lower molecular weights. Churning Process or Xanthation: The cellulose crumbs are allowed to react with carbon disulphide to form cellulose xanthate. Mixing or dissolving Process: The yellow crumb is dissolved in an aqueous solution. Ripening Process: The viscose is allowed to stand for a period of time. Filtering: Its filtered to remove any undissolved materials that could cause defects.
  • 8. Degassing: Bubbles of air that could also cause defects are removed. Spinning Process: The material is moved into a bath containing; sodium sulphate, sulphuric acid and zinc sulphate. This causes the rayon filaments to bond together tightly. Drawing: The newly bonded rayon filaments are stretched. Washing: The rayon gets washed to remove any impurities that may remain. 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.
  • 10. Rayon Properties Physical: Fluid drape, soft hand, control lustre, length, diameter. Mechanical: Regular: Weak, especially wet. HWM: Stronger, adequate breaking elongation. Chemical: Absorbent, dyes well, high regain, smooth, soft, good heat & static conductor. Appearance retention: Moderate Regular: poor resiliency, progressive shrinkage HWM: less wrinkling, accepts durable press & dimensional stability finishes, can be mercerized Care: Regular: limited wash ability (wrinkling, loss of sizing, excessive shrinkage) dry clean HWM: greater wash ability, less wrinkling, shrinkage may be controlled
  • 11. Environmental Impacts of Fabric: Rayon Rayon requires raw wood, usually hemlock or pine, and a great deal of water and energy to process. Here's a fun fact: Port Angeles, WA was once home to a pulp mill that produced the raw cellulose needed to make rayon and a number of other products. Today, it's a toxic clean-up site. The company's name? Rayonier. This is another artificial fibre, made from wood pulp, which on the face of it seems more sustainable. However, old growth forest is often cleared and/or subsistence farmers are displaced to make way for pulpwood plantations. Often the tree planted is eucalyptus, which draws up phenomenal amounts of water, causing problems in sensitive regions. To make rayon, the wood pulp is treated with hazardous chemicals such as caustic soda and sulphuric acid.