Polyethylene Terephthalate: How it’s made, Properties, Uses and The Olden Days

Updated: Mar 5

How is it made?

The uncomplicated version would be: Polyethylene Terephthalate occurs when Ethylene glycol and Terephthalic acid go through this mechanism called Step-growth Polymerisation. Then, it comes out in the form of a molten, sticky mass that can be turned immediately into fibre or solidified for plastic production.


Polyethylene Terephthalate is a rigid, strong and clear material that works as a good barrier to oxygen, water and carbon dioxide. Not only it is hard to break it’s also compatible with most solvents, including hot ones. Some might know it as Dacron by DuPont or by one of its most famous alias: PET.

PET fibres are no exception either. Their rigidity makes them of great value - since they do not deform easily and are very resistant to wrinkling in fabric - they are often blended with rayon, wool, and cotton. In the fashion industry Polyethylene Terephthalate is best known as: Polyester.

Common Uses

It’s one of our favourites when it comes to plastic bottles for soft drinks, water, juice, beer and mouthwash. We also like to use it for food jars for our peanut butters, jellies, jams and pickles. If we’re in the mood for it we can even pop it in oven or microwave it as food trays and/or containers.

After we use it and abuse it, when recycled - which is something we will talk about in the weeks ahead - we can make it into fibres for carpets, cosy fleece jackets, tote bags. It can also be (re)transformed into containers for food and beverages – which is something we will, indeed, talk about it in the weeks ahead.

The olden days

PET was patent in 1941 by J. Rex Whinfield and James T. Dickson in Great Britain, but because the world had its hands full, per se, its production didn’t start up until 1954.