General Properties
Short Name:
Name:
SB
Styrene/Polybutadiene copolymer
SB is a copolymer from styrene and butadiene (and sometimes additional components), in which the individual monomers are lined up either in block form (block copolymer) or one monomer is grafted on the main chain of the second monomer (graft copolymer).
Structural Formula
Properties
| Glass Transition Temperature | -90 to -50 / 80 to 110°C |
|---|---|
| Melting Temperature | - |
| Melting Enthalpy | - |
| Decomposition Temperature | 440 to 455°C |
| Young's Modulus | 1800 to 2500 MPa |
| Coefficient of Linear Thermal Expansion | 70 *10-6/K |
| Specific Heat Capacity | 1.2 to 1.3 J/(g*K) |
| Thermal Conductivity | 0.17 to 0.18 W/(m*K) |
| Density | 1.05 g/cm³ |
| Morphology | Amorphous thermoplastic |
| General properties | High transparency, high toughness and stiffness |
| Processing | Injection molding, extrusion, deep drawing |
| Applications | Packaging, toys |
NETZSCH Measurement
| Instrument | DSC 204 F1 Phoenix® |
| Sample Mass | 12.17 mg |
| Isothermal Phases | 5 min |
| Heating/Colling Rates | 10 K/min |
| Crucible | Al, pierced lid |
| Atmosphere | N2 (40 ml/min) |
Evaluation
Both for block and graft copolymers, the characteristic properties of the monomers are largely retained so that SB has two glass transitions. The glass transition in the low-temperature range (here in both heatings at -84°C, midpoint) is due to the butadiene component. The glass transition at 98°C (2nd heating, red, midpoint) is due to the styrene component. The irreversible effect in the 1st heating (peak temperature 76°C) indicates the release of strong tensions in the material that are caused by the thermomechanical history of the polymer.