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Polyester is made up of a long chain of several ester units. It is a result of condensation polymerization reaction taking place between carboxylic acid and alcohol. Apart from the chemically prepared polyesters, there are many natural polyesters too. Natural polyesters including some synthetic ones are biodegradable but rest of them are not. Depending upon the structure of the polyesters, they can be thermoplastic or thermoset.

Types of Polyester

Polyesters can be divided into two categories, saturated and unsaturated.

Saturated Polyester: These polyesters have a saturated backbone. This is the reason why they are not as reactive as unsaturated ones. With low molecular weight they are used as plasticizers and are used to make linear, high molecular weight thermoplastics like Dacron and Mylar which are polyethylene terephthalate.

Unsaturated Polyester: As the name suggests, the backbone of these polyesters are made from an unsaturated substance which is alkyl thermosetting resin. It is more reactive than saturated polyesters and is used in making reinforced plastics.

Characteristic Properties

Let's find out the characteristic properties of a polyester.
  • Polyesters have immense strength. They are strong and hence their products are very durable and long-lasting.
  • They are bad absorbents of water hence, polyester fabric dries very fast.
  • They are resistant to chemicals and many biological agents like mold, mildew, etc.
  • They can be easily washed as the dirt does not enter the fibers.
  • Polyesters are resistant to wrinkles, shrinking, stretching, abrasion etc. Hence, they are very durable.
  • They can be used for the purpose of insulation.
  • They are highly inflammable and care should be taken if they are worn as garments.
Uses

Polyester has many beneficial properties which makes it very useful and significant. Following are some of its uses.
  • Polyester is used as a fabric. With the help of extruder, very fine thread of PET is produced which is used as polyester fabric. It is silky and smooth to touch. It was one of the most famous fabrics in the 70s and the disco clothing of that era was made out of polyester. Even today you get garments made out of this fabric which are durable and very useful.
  • It is also used in home furnishings like curtains, bedspreads, carpet, sheets, pillows, etc. They are easy to wash and quick to dry hence, they can be washed at home.
  • Polyester is used in wet and damp environment because of its hydrophobic characteristic. It can be coated with water resistant coating which will add to its non water absorbing quality.
  • It is used to make climbing suits, sleeping bags, winter dry suits, etc. This is because of the insulating quality of polyester. It does not allow the air to come in and trap the warmer air inside.
  • Polyesters are used in making PET bottles. These bottles can be recycled and hence, are not harmful to nature.
  • They are used in making decorative balloons. This is made from a kind of polyester known as Mylar.
  • Apart from the above mentioned uses, polyesters are also used as sails, floppy disk liners, high strength ropes, thread, hoses, power belting, etc.
Take proper polyester fabric care so as to increase the shelf life of your clothes.