Types of synthetic fibers

RAYON:

Towards the end of the nineteenth century, scientists were successful in obtaining a fiber having properties similar to that of silk. Such a fiber was obtained by chemical treatment of wood pulp. This fiber was called rayon or artificial silk. Although rayon is obtained from a natural source, wood pulp, yet it is a man-made fiber.  

Rayon is produced from the natural fiber in the following steps:

• Pure cotton or cellulose is soaked in 30% solution of caustic soda for three hours.
• The caustic soda solution is then removed and the product is gently warmed with carbon disulphide. The product so formed is called cellulose xanthate.
• Cellulose xanthate is again dissolved in caustic soda solution, when it forms another product commonly called viscose solution. This solution is carefully filtered to remove any insoluble impurities.
• The viscose solution is then slowly passed through a spinneret placed in the bath of dilute sulphuric acid. The viscose hardens to form a very fine filament. The filament is then wound on a spool.

Characteristics of Rayon:

• Rayon is cheaper than silk and can be woven like silk fibers.
• Rayon is highly absorbent, soft and comfortable.
• It is easy to dye in a wide range of colors, and drapes well.

Uses of Rayon:

The filament of rayon can be woven like any other natural fibers. They have a feel and texture of natural silk. Following are the uses of rayon :

• Rayon filaments are blended with wool in the manufacture of carpets.
• Rayon filaments are blended with cotton to make smooth silky cloth, which can be used for making bed sheets.
• Long filaments of rayon are used for making reinforced automobile tyres.

NYLON:

Nylon is another man-made fiber. In 1931, it was made without using any natural raw material (from plant or animal). It was prepared from coal, water and air. It was the first fully synthetic fiber. Nylon fiber is strong, elastic and light. It was lustrous and easy to wash. So, it became very popular for making clothes.

It is a superior type of synthetic fiber, which is truly artificial, as it does not use any natural fiber as its raw material. It is prepared by the polymerization of amide molecules. The amide molecules are obtained from petroleum products by complex chemical process. The nylon fiber consists of a very long chain of polyamide molecules. The nylon fibers are elastic, strong and water resistant.

The term Nylon used for polyamide molecules is named after two cities, New York in USA and London in Great Britain. NY stands for New York and Lon for London. It is because this product was developed by the collective effort of scientists of two countries.

Nylon fiber is highly elastic, tensile and has silk like appearance. The women’s stockings made from Nylon were instant hit in the market, when they were introduced in 1939.

However, in 1939 when this product was introduced, the World War II started. So, most of its production was diverted to making parachutes.

However, when the war ended in 1945, the production of stocking again started. There was such a great demand that supply could not match. There was a huge black market for this product. Women have to wait for hours in queues to get a pair of stockings.

Uses of Nylon:

• It is used for making fabric for clothing and parachutes. It is used for making stockings on account of its high elasticity.
• It is used for making ropes for rock climbing and fishing nets.
• It is used for making common household articles, such as tooth brushes, combs, zip-fastener, hooks.
• It is used for making tyre cords and strings for tennis racquets, etc.
• It is used for making small parts of machines, such as washers, pulleys.

POLYESTER

Polyester is another synthetic fiber. Fabric made from this fiber does not get wrinkled easily. It remains crisp and is easy to wash. So, it is quite suitable for making dress material. Terylene is popular polyester. It can be drawn into very fine fibers that can be woven like any other yarn. PET is a very familiar form of polyester. It is used for making bottles, utensils, films, wires and many other useful products.

Esters are the compounds formed, when alcohol is made to react with organic acids, such as acetic acid, phallic acid. The esters have fruity smell. The ester molecules can be polymerized to form polyester. The polyester can be drawn into very fine filaments so as to form artificial fiber. There are a number of varieties of esters, depending upon the alcohol and the organic acid used to form the molecules of ester.

TERYLENE OR TERENE OR DACRON:

These polymers are obtained by polymerising the molecules of phallic acid and ethene glycol. Terylene filaments are similar, but superior in properties than nylon. They are put to following uses:

Uses of Terylene:

• It is largely used for making fabrics for shirts, trousers, sarees and other dress materials. The fabrics are sold by the trade names of polycot or terrycot, polywool, etc. As the name suggests polycot or terrycot is a blend of cotton and polyester or terylene fibers. Similarly, polywool or terywool is a blend of wool and polyester or terylene.
• It is used for making sails for sailing boats.
• It is used for making fire hoses and conveyor belts.

POLYETHENE TETRAPHTHALATE (PET):

It is prepared by the polymerisation of ethene tetraphthalate. It can be easily drawn into very fine filaments, which can be woven like any other yarn.

Uses:

• It is largely used for making synthetic clothes. These clothes have a permanent crease and are easy to wash.
• It is used for making containers for packaging food and soft drinks. PET bottles are commonly used in industry for selling all kinds of soft drinks, oils and other food articles.
• It is used for making magnetic tapes used in audio cassette recorders and video cassette recorders.

ACRYLIC:

We wear sweaters and use shawls or blankets in the winter. Many of these are actually not made from natural wool, though they appear to resemble wool. These are prepared from another type of synthetic fiber called acrylic. The wool obtained from natural sources is quite expensive, whereas clothes made from acrylic are relatively cheap. They are available in a variety of colors. Synthetic fibers are more durable and affordable which makes them more popular than natural fibers.

Acrylic fiber is obtained by the polymerisation of molecules of acrylonitrite (which is a complex molecule obtained by complex chemical processes from petroleum products). These fibers are very light and soft like wool. They are resistant to weathering.

Uses of Acrylic Fibers:

They are used for making yarn for hand knit sweaters. They are also used for making blankets and shawals, which are very light and as warm as woollen blankets. Articles made from acrylic are very cheap as compared to the articles made from wool.

KOROSEAL:

It has a trade name of high polymer of vinyl chloride.

Uses of Koroseal:

Koroseal is water proof as well as air proof. It is used for coating fabrics of silk, rayon or cotton to make them waterproof. Waterproof fabrics so obtained can be used on rainy days or as bathroom curtains.