General Properties
Short Name:
Name:
TPA
Thermoplastic Polyamide Elastomer
Thermoplastic elastomers on a polyamide basis (TPAs) belong to the copolymers with alternating succession of hard and soft segments. The block of the hard segments show amide bonds, the soft segments ether or ester bonds.
Structural Formula
Properties
| Glass Transition Temperature | -70 to 45°C |
|---|---|
| Melting Temperature | 145 to 200°C |
| Melting Enthalpy | 20 to 65 J/g |
| Decomposition Temperature | 400 to 420°C |
| Young's Modulus | 20 to 500 MPa |
| Coefficient of Linear Thermal Expansion | 120 to 240 *10-6/K |
| Specific Heat Capacity | 2.4 to 2.8 J/(g*K) |
| Thermal Conductivity | 0.2 W/(m*K) |
| Density | 0.99 to 1.10 g/cm³ |
| Morphology | Thermoplastic elastomer, copolymer with hard and soft segments |
| General properties | Good resistance to fuels and lubricating greases |
| Processing | Injection molding, extrusion, blow molding |
| Applications | Automotive industry (seals, hoses) |
NETZSCH Measurement
| Instrument | DSC 204 F1 Phoenix® |
| Sample Mass | 11.70 mg |
| Isothermal Phase | 8 min / 3 min / 8 min |
| Heating/Colling Rates | 10 K/min |
| Crucible | Al, pierced lid |
| Atmosphere | N2 (40 ml/min) |
Evaluation
In the 1st heating (blue), this example of TPA shows a glass transition at -60°C (midpoint) with a step height Δcp of 0.40 J/(g.K). After a broad, but flat exothermal effect with a peak temperature of 32°C (probably a small cold-crystallization) melting of the hard segments occurred in the temperature range between approx. 80°C and 170°C (with a main peak at 153°C and a preceded shoulder at 121°C). In the 2nd heating (red), an exothermal effect can no longer be seen. Both the glass transition and the endothermal melting range remained. The glass transition temperature (midpoint) occurred at -61°C; the melting range with main peak at 150°C is not that strongly structured like in the 1st heating. The heat of fusion has almost decreased by half compared to the 1st heating (just under 20 J/g compared to 36 J/g).