PET
Polyethylene Terephthalate
Glass Transition (Tg)
76–80 °C
Melting Point (Tm)
250–260 °C
Density
1.38–1.40 g/cm³
CAS Number
25038-59-9
Recycling Code
♺ 1
Category
Commodity
Repeat Unit
–[O–CH₂CH₂–O–CO–C₆H₄–CO]ₙ–
The repeating unit is the smallest structural fragment whose repetition builds the whole chain. Subscripts show the relative share of each unit in copolymers.
Key Properties
Crystallinity strongly process-dependent; excellent gas barrier when biaxially oriented; must be dried before processing to avoid hydrolytic degradation.
Applications
Beverage bottles, polyester fibre, thermoformed trays, films.