FKM
Fluoroelastomer (Viton)
Glass Transition (Tg)
-20 °C
Melting Point (Tm)
—
Density
1.80–1.85 g/cm³
CAS Number
9011-17-0
Recycling Code
None
Category
Elastomer
Repeat Unit
–[CH₂–CF₂]ₓ–[CF₂–CF(CF₃)]ᵧ–
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
Best-in-class heat (to 250 °C) and fluid resistance among elastomers; poor low-temperature performance; very expensive.
Applications
Aerospace and engine O-rings, chemical-plant seals, fuel systems.