PMP
Polymethylpentene (TPX)
Glass Transition (Tg)
20–30 °C
Melting Point (Tm)
235–240 °C
Density
0.83 g/cm³
CAS Number
25068-26-2
Recycling Code
♺ 7
Category
Engineering
Repeat Unit
–[CH₂–CH(CH₂CH(CH₃)₂)]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
Lowest density of all commercial solid plastics (0.83); transparent despite being semi-crystalline because amorphous and crystalline refractive indices match.
Applications
Autoclavable labware, release film, microwave and medical components.