SBS
Styrene-Butadiene-Styrene
Glass Transition (Tg)
-90 (PB) / 100 (PS)
Melting Point (Tm)
—
Density
0.94–1.00 g/cm³
CAS Number
9003-55-8
Recycling Code
♺ 7
Category
Elastomer
Repeat Unit
–[CH₂–CH(C₆H₅)]ₐ–[CH₂–CH=CH–CH₂]_b–[CH₂–CH(C₆H₅)]ₐ–
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
Classic thermoplastic elastomer: glassy PS domains physically crosslink the rubbery PB matrix, so it can be melted and reprocessed; unsaturated so ozone-sensitive.
Applications
Bitumen modification for roads, shoe soles, adhesives, toys.