EVERYDAY MATERIALSAtlas
Polymers / Thermoplastic polyester

PET

Polyethylene terephthalate, or PET, is a polyester used in clear drinks bottles, films and fibres. The chemistry is shared, but processing creates very different structures. Stretching a bottle preform improves the useful orientation of its polymer chains; spinning and drawing a fibre makes a textile filament. PET is not polyethylene, despite the similar name, and a bottle is not necessarily made from exactly the same grade as a jacket.

See it in everyday life
AI-generated representative illustration: clear plastic bottle with a blue closed cap.Plastic drink bottleBottle wallSoap dispenserRefillable bottle

Useful properties

Why it earns its place

Clarity ↗

Suitable processing produces transparent packaging walls.

Useful gas barrier ↗

PET slows gas movement enough for many beverage-packaging designs.

Strength when oriented ↗

Stretching helps create thin, useful bottle walls and fibres.

From input to useful material.

A simplified industrial pathway. Select a stage to learn what changes. Recycled feedstock and other process variants can enter at different stages.

  1. 01 Chemical building blocks
  2. 02 Polymerization
  3. 03 Drying and preform moulding
  4. 04 Stretch blow moulding
  5. 05 Bottle filling and use

Origins & processing

PET is made by reacting chemical building blocks, commonly terephthalic acid and ethylene glycol, to form long chains. Conventional feedstocks come mainly from petrochemical routes; some ingredients can have other origins. Resin is dried and processed under controlled conditions. Bottles commonly begin as injection-moulded preforms that are reheated, stretched and blown into shape. Fibre production uses spinning instead. Recovered PET can provide feedstock, but contamination, molecular degradation and application requirements determine the additional treatment needed.

Where it turns up

A drinks bottle, polyester fleece and a thin film can share PET chemistry while demanding different purity, colour and performance. Bottle closures are often made from another polymer. Some packaging also uses coatings or extra layers, so identifying the bottle body does not establish the entire pack’s construction or recycling behaviour.

Useful, with limits.

PET has finite gas-barrier and temperature performance; not every bottle is designed for hot filling or repeated use. Colour, labels, adhesives and multilayer structures can complicate recycling. A transparent appearance is not a reliable polymer identifier. Recycled content describes an input, while recyclability describes a potential output route; one does not guarantee the other.

A next life depends on the system.

Collected bottles can be sorted, washed and processed into new feedstock, sometimes for bottles and sometimes for other products. Food-contact applications need appropriate controls. Textiles made from the same polymer usually enter different collection systems and are harder to separate from blends. Check local acceptance of the complete packaging item rather than relying only on its resin code.

Choose your next question

Keep the connection going.

Where else is it used?2 objects in this atlas link to pet.Where does it come from?Follow the industrial process and its inputs.What happens after use?Return to the whole object and its recovery choices.

Follow the evidence

Original explanations informed by the sources below. Technical and industry sources support material behaviour; industry environmental marketing is not treated as a universal comparison. Browse the source register.