Rayon is known as artificial silk .Rayon is one of the most peculiar fabrics in commercial use today.
Strictly speaking, it is not an artificial fiber, because it is derived
from naturally occurring cellulose. It is not, however, a natural
fabric, because cellulose requires extensive processing to become rayon.
Rayon is usually classified as a manufactured fiber and considered to
be “regenerated cellulose”.
Rayon is the oldest manufactured
fiber, having been in production since the 1880s in France, where it was
originally developed as a cheap alternative to silk . Rayon is used in a variety
of textile applications, including shirts and skirts, and appears in
both woven and knitted forms. The fabric has gained an unfair reputation
because it is frequently used in cheaply constructed garments that do
not stand up to heavy wear. However, rayon is an excellent, nicely
draping alternative to silk
The manufacture of rayon begins with cellulose, frequently extracted from wood pulp. The
cellulose is steeped in caustic soda, which concentrates some of the
cellulose into soda cellulose, which is then rolled or pressed to remove
excess soda solution. After pressing, the cellulose is shredded into a
substance called white crumb.
The white crumb is allowed to oxidize, forming shorter molecular chains, and treated with carbondisulphide. The soda cellulose reacts with this substance, forming yellow crumb
due to inorganic compounds that emerge during the chemical process.
This yellow crumb is dissolved in a caustic solution, which relaxes the
hydrogen bonds in the cellulose, producing a highly viscous substance.
This substance gives its name to the manufacturing process, called the viscose process.
This viscous fluid is allowed to age, breaking down the cellulose
structures further to produce an even slurry, and then filtered to
remove impurities. Small air pockets are forced out to ensure a strong,
even fiber, and the mixture is forced through a spinner, which forms
many even strands of fine thread that enter a setting solution to form
cellulose filaments: also called rayon. The rayon is stretched to form a
strong, even bond, washed, and then formed into rayon fabric.
This complex process results in a great deal of environmental
pollution, inspiring a drive to clean up the industry. The rayon
industry has also suffered from the development of cheaper artificial
fabrics with a much shorter manufacturing process, such as nylon.
Rayon is frequently blended with true synthetic fabrics for various
applications, and it is advisable to follow individual care labels on
rayon garments, as these blends have specific handling needs.
|
