PET has a highly symmetrical molecular structure, a good crystal orientation ability, and an excellent optical property and weather resistance. Amorphous PET enjoys outstanding optical transparency. In addition, PET has superior wear resistance, friction, dimensional stability, and electrical insulation.

Bottles made from PET have characteristics of high strength, good transparency, non-toxicity, anti-penetration, lightweight, and high production efficiency. This article will introduce seven aspects of PET, including profile, development, classification, synthesis process, application, and recycled one.
PET is short of polyethylene terephthalate. The color is milky white or light yellow. When it becomes a highly crystalline polymer, its surface is smooth and shiny. Its physical and mechanical property is very fine and long-term usage temperature could reach 120℃. What’s more, its electrical insulating property is excellent and it can remain pretty good electrical performance even under high temperature and frequency.
molecular structural formula of PET
The above picture is the molecular structural formula of PET.
As a member of the thermoplastic polyester family, its body (main chain) contains DNA molecules of “-COO-” and PET is a linear polymer. There are many polymers similar to PET, like PBT, PTT, PCT, PEN, PBN, etc. They generally share the same application of engineering plastic and synthesized from an aromatic diacid and various dihydric alcohol. The below table is the performance contrast between PET and other thermoplastic polyesters.
contrast between PET and other thermoplastic polyesters
In 1946, The United Kingdom published the first patent for PET manufacturing.
In 1949, the UK ICI company finish the test.
In 1953, the USA Dupont company realized industrial production first in the world.
At the initial stage, nearly all the PET is used for synthetic fiber, which is called dacron in China. Since the 80’s, there has been a breakthrough development for PET as an engineering plastic. The nucleating agent and crystallization promoter have been developed successively.
PET is divided into fiber grade and non-fiber grade. And non-fiber PET can be classified into Non-engineering plastic grade and engineering plastic grade.
Synthesis Process
PET Synthesis Progress Flow Chart
1 Polyester Fiber
Polyester has many excellent textile properties and wearability. It has a wide range of applications, including pure textile production and interweaving with cotton, wool, silk, and other chemical fiber.
Terylene can also be used for non-woven fabric, which can be applied for indoor decoration, carpet backing, medical industry, liner, etc.
2 Bottles, Film Sheet and Engineering Plastics
Currently, non-fiber polyesters are mainly used in the production of bottles, films, and engineering.
When used for bottles, it has characteristics of lightweight, high transparency, heat resistance, pressure resistance, and good barrier to carbon dioxide gas.
When used for film, it is colorless transparent, and shiny. And what’s more, the films have fine mechanical properties, high hardness, and toughness.
As for engineering plastics, it is widely used in electronic and electrical, automobile, machinery, light industry, construction, national defense, and daily life.
Recycled PET
During recent years, with the update of recycled PET process technology and improvement of product quality, the recovery and reuse rate of recycled PET has been sharply increased. For more information, please find it in