Polyester Plastics – Properties And Features

Polyester is a general term that encompasses all the polymers whose main polymer backbones are formed by esterification and condensation of polyfunctional alcohols and acids. The hydrolysis by acids yield long chain polyesters which are used in a number of industries. India is the known producer of high quality polyesters to be used in different industries.

Basically two classes of polyesters are known: Thermoplastics which are also known as polybutylene terephthalate (PBT) and polyethylene terephthalate (PET), and another class of polyester includes thermosets.

Thermoplastics are actually polymers which become moldable or pliable above a specific temperature but return to solid state upon cooling. Thermoplastics have high molecular weight and their chains are bounded by intermolecular forces which allows it to be remolded because intermolecular interactions spontaneously reform on cooling.

Thermoplastic polyesters are the most demanded form of polyesters with vast applications in engineering industry. The main reason behind the popularity of this material is that polyester fit into those applications which are not readily filled by other plastics, meanwhile it also compete in other applications and does necessary task which other plastics do.

On the other hand, thermoset or thermosetting plastic irreversibly cures and that may be through heat or chemical reaction or through irradiation. These are generally stronger than thermoplastic polyester due to the cross-linking or three-dimensional network of bonds. In fact thermosets are brittle.

Initially, researchers studied only linear polymers or polyesters but in 1941 Whinfield and Dickson created first PET polyester fiber. Following the research, there were several modifications and advancements which expanded the base of polyesters in different forms in different industries. India has also registered its name among the top polyester manufacturers of the industry and polyester India is demanded in various countries in one or other form.

The outstanding features of polyester plastic make it the most sought after material in the industry. Good dimensional stability, flame retardant, excellent processability, high heat resistance, chemical resistance, wonderful electrical properties, antistatic, acid resistance, bacteria resistance etc are some of the features which add to the overall demand of polyester.

Polyester plastics are used in several industries for variegated purposes. These are used in electrical/electronic applications, connectors, film, housing, engineering parts, communication, electrical parts, automotive and other fields.

Apart from having various advantages, polyester plastics are also known for some disadvantages. For instance, they are not suitable for hot water service, they are chemical resistant but poorly. One can't even ignore the chances of cracking and post-mold warpage.