PIB
Polyisobutylene
Glass Transition (Tg)
-73 °C
Melting Point (Tm)
—
Density
0.92 g/cm³
CAS Number
9003-27-4
Recycling Code
None
Category
Elastomer
Repeat Unit
–[CH₂–C(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
Fully saturated with extremely low gas permeability and permanent tack; oxidatively very stable.
Applications
Insulating-glass sealants, chewing-gum base, adhesive tackifier.