What is PET Plastic: The Basics
Before we discuss the ins and outs of PET plastic, you might be wondering what PET plastic stands for. PET is short for its chemical name: polyethylene terephthalate.
You may also see PET abbreviated as PETE, PETG, APET, PETP or PET-P. Similarly to how tissue paper is commonly referred to as “Kleenex”, PET plastic may be referred to as it’s brand names Dacron (US), Terylene (UK), or Lavsan (Russia).
PET has many properties that make it desirable for a wide range of applications. In appearance, PET is clear and transparent. It is somewhat flexible, yet still strong and will not tear easily. It is lightweight and can be easily shaped when molten.
Your house almost certainly contains many products made from PET. Bottled water, shampoo containers, soda bottles, and plastic cups are ofter made from PET plastic. Many fabric products also use PET in the form of polyester.
Is PET Plastic Safe?
Yes! PET has been safely used since the 1940’s. According to the FDA, PET plastic can be safely used with all forms of food and beverage. Numerous studies and testing confirm the FDA’s decision to label PET as safe for food use. It does NOT contain any BPA.
Is PET Plastic Recyclable?
Yes! PET is 100% recyclable. It is the most commonly recycled plastic in the world. It can be simply washed and melted down for uses in lower grade products, or hydrolysed down to monomers, which are purified and re-polymerised to make new food-grade PET. The video below shows another popular method to recycle PET, by turning it polyester clothing.
As of 2017, about 29.2% of PET plastic is recycled in the United States. If you are looking to recycle your own PET plastic products, you can identify PET material by looking for the number 1 within the continuous arrows.
While recycling is the preferred method of PET disposal, it is safe to landfill. It won’t biodegrade on its own so it will not contaminate the surrounding areas, though Japanese scientists have recently discovered a species of bacteria capable of quickly degrading PET plastic.
A Brief History of PET Plastic
Initial development of PET was done in the labs of the Calico Printers Association in the United Kingdom. It was first prepared in 1940 during a study of phthalic acid. They were granted a patent for their efforts in 1941.
The first North American use of PET was in the mid 1940’s by a group of DuPont scientists.
By the late 1950s, PET could be manipulated into PET film. Later into the 1970’s, PET was being used in many of the ways we see today. In plastic bottles for example.
The Science and Creation of PET
PET plastic comes from the polymerization of terephthalic acid and ethylene glycol. With the aid of catalysts, the two materials are heated together in low vacuum pressure to produce molten PET. As the liquid becomes thicker, the polymer chains grow. The reaction is stopped when the desired polymer chain length is achieved.
This produces thin strands of PET which are extruded and cooled. The strands are cut into pellets which can be remelted and stretched later to produce the desired material. The video below outlines the process of getting from these pellets to plastic bottles (Skip to 28 seconds in).
The chemical formula for PET is (C10H8O4)n. It has a density of 1.38 g/cm3. It melts as 482 °F and boils at 662 °F.
The Future of PET
The short term future of PET is bright. It is a cheap, lightweight material with a huge variety of uses. It keeps food and drink safe all over the world, makes some great clothing, and even is helping the fight against malaria.
The long term future depends largely on how the issue of plastic pollution is solved. Will we continue to litter our oceans and forests with plastic? Will advancements in science and technology further improve recycling processes? Will PLA continue to grow in popularity as a more environmentally friendly solution? Only time will tell!