Sunday, November 27, 2016

Production process and Uses of Cotton


Cotton is a soft, fluffy staple fiber that grows in a boll, or protective capsule, around the seeds of cotton plants of the genus Gossypium in the family of Malvaceae. The fiber is almost pure cellulose. Under natural conditions, the cotton bolls will tend to increase the dispersion of the seeds.


Gossypium  hirsutum
Gossypium  barbadense
Gossypium  arboreum 
Gossypium  herbaceum


Organic cotton is generally understood as cotton, from plants not genetically modified, that is certified to be grown without the use of any synthetic agricultural chemicals, such as fertilizers or pesticides..

Genetically modified (GM) cotton was developed to reduce the heavy reliance on pesticides. The bacterium Bacillus thuringiensis (Bt) naturally produces a chemical harmful only to a small fraction of insects, most notably the larvae of moths and butterflies, beetles, and flies, and harmless to other forms of life.


1. Cotton is used to make highly absorbent bath towels and robes. 
2. Most T-shirts are made from cotton.
3. Bed sheets often are made from cotton
4. Cotton also is used to make yarn used in crochet and knitting.
5. Cotton is used in fishing nets, coffee filters, tents, explosives manufacture, cotton paper, and in 
6. The first Chinese paper was made of cotton fiber.


Silk is a natural protein fiber, some forms of which can be woven into textiles. The protein fiber of silk is composed mainly of fibroin and is produced by certain insect larvae to form cocoons. The best-known silk is obtained from the cocoons of the larvae of the mulberry silkworm Bombyx mori reared in captivity.


1. Silk fibers from the Bombyx mori silkworm have a triangular cross section with rounded corners, 5–10         μm wide.
2. Silk has a smooth, soft texture that is not slippery, unlike many synthetic fibers.
3. Silk is one of the strongest natural fibers, but it loses up to 20% of its strength when wet.
4. Silk is a poor conductor of electricity and thus susceptible to static cling.
5. Silk is resistant to most mineral acids, except for sulfuric acid.
6. The addition of alanine and serine makes the fibers strong and resistant to breaking.

Production process: 

The entire production process of silk can be divided into several steps which are typically handled by different entities. Extracting raw silk starts by cultivating the silkworms on mulberry leaves. Once the worms start pupating in their cocoons, these are dissolved in boiling water in order for individual long fibres to be extracted and fed into the spinning reel.


1. Silk's absorbency makes it comfortable to wear in warm weather and while active.
2. Its low conductivity keeps warm air close to the skin during cold weather. 
3.     It is often used for clothing such as shirts, ties,blouses, formal dresses, high fashion clothes, lining,        
4. It is used for upholstery, wall coverings, window treatments (if blended with another fiber), rugs, 
        bedding and wall hangings.
5. Silk has had many industrial and commercial uses, such as in parachutes, bicycle tires.
6. Silk's attractive luster and drape makes it suitable for many furnishing applications.

To be continue.....

Properties and Production of Dacron


Polyethylene terephthalate is the most common thermoplastic polymer resin of the polyester family and is used in fibers for clothing, containers for liquids and foods, thermoforming for manufacturing, and in combination with glass fiber for engineering resins.
It may also be referred to by the brand name Dacron.


1. PET in its natural state is a colorless, semi-crystalline resin.

2. PET can be semi-rigid to rigid, and it is very lightweight. It makes a good gas and fair moisture barrier,           as well as a good barrier to alcohol and solvents.

4.     It is strong and impact-resistant.

5.     PET becomes white when exposed to chloroform and also certain other chemicals such as toluene.


Polyethylene terephthalate is produced from ethylene glycol and dimethyl terephthalate (C6H4(CO2CH3)2) or terephthalic acid. Dimethyl terephthalate process:

Polyesterification reaction in the production of PET.

In dimethyl terephthalate process, this compound and excess ethylene glycol are reacted in the melt at 150–200 °C with a basic catalyst. Methanol (CH3OH) is removed by distillation to drive the reaction forward. Excess ethylene glycol is distilled off at higher temperature with the aid of vacuum. The second transesterification step proceeds at 270–280 °C, with continuous distillation of ethylene glycol as well.The reactions are idealized as follows:

First step:

C6H4(CO2CH3)2 + 2 HOCH2CH2OH → C6H4(CO2CH2CH2OH)2 + 2 CH3OH
Second step:

n C6H4(CO2CH2CH2OH)2 → [(CO)C6H4(CO2CH2CH2O)]n + n HOCH2CH2OH


Cotton is a soft, fluffy staple fiber that grows in a boll, or protective capsule, around the seeds of cotton plants of the genus Gossypium in the family of Malvaceae. The fiber is almost pure cellulose. Under natural conditions, the cotton bolls will tend to increase the dispersion of the seeds.


Gossypium  hirsutum
Gossypium  barbadense
Gossypium  arboreum 
Gossypium  herbaceum

To be continue.....

Importance and Uses of Polyester Fibers

Polyester :

Polyester is a category of polymers that contain the ester functional group in their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate (PET). polyesters include occurring chemicals, such as in the cutin of plant cuticles, as well as synthetics through step-growth polymerization such as polybutyrate.

The main raw materials:
  •  Purified terephthalic acid (PTA) or 1,4 benzenedicarboxylic acid,
  • Dimethylterephthalate (DMT) or1,4 benzenedicarboxylic acid dimethyl ester

  • Mono Ethylene Glycol (MEG) or 1,2 ethanediol

Production of Polyester: 

Synthesis of polyesters is generally achieved by a poly condensation reaction. The general equation for the reaction of a diol with a diacid is :

(n+1) R(OH)2 + n R´(COOH)2 → HO[ROOCR´COO]nROH + 2n H2O

Aliphatic polyesters can be assembled from lactones under very mild conditions, catalyzed anionically, cationically or metallorganically. A number of catalytic methods for the copolymerization of epoxides with cyclic anhydrides have also recently been shown to provide a wide array of functionalized polyesters, both saturated and unsaturated.

Importance of Polyester:

1.    The relatively easy accessible raw materials PTA or DMT and MEG
2.    The very well understood and described simple chemical process of polyester synthesis
3.  The low toxicity level of all raw materials and side products during polyester production and processing
4.    The possibility to produce PET in a closed loop at low emissions to the environment
5.    The outstanding mechanical and chemical properties of polyester
6.    The recyclability
7.    The wide variety of intermediate and final products made of polyester.

Uses of Polyester:

      1. Polyester fiber is used as cushioning and insulating material in pillows, comforters and upholstery padding.

    2. Polyesters are also used to make bottles, films, tarpaulin, canoes, liquid crystal displays, holograms, filters, dielectric film for capacitors, film insulation for wire and insulating tapes.

     3. Polyesters are widely used as a finish on high-quality wood products such as guitars, pianos and vehicle/yacht interiors.

To be continue........