General Properties
Short Name:
Name:
PA6.6
Polyamide 6.6
Along with PA6, PA6.6 is one of the most frequently used polyamides and belongs to standard plastics. As already mentioned for other polyamides, PA6.6 can absorb humidity (e.g., air humidity). This allows for a higher flexibility and toughness, but, at the same time, reduces hardness and strength. It can also result in volume changes in the material. Polyamide 6.6 (PA6.6) is produced by a polycondensation reaction between hexamethylene diamine and adipic acid. F
Structural Formula
Properties
| Glass Transition Temperature | 65 to 90°C |
|---|---|
| Melting Temperature | 225 to 265°C |
| Melting Enthalpy | 185 J/g |
| Decomposition Temperature | 430 to 473°C |
| Young's Modulus | 3000 MPa |
| Coefficient of Linear Thermal Expansion | 35 to 45 *10-6/K |
| Specific Heat Capacity | 1.67 to 1.70 J/(g*K) |
| Thermal Conductivity | 0.24 to 0.33 W/(m*K) |
| Density | 1.13 to 1.16 g/cm³ |
| Morphology | Semi-crystalline thermoplastic |
| General properties | Good mechanical strength. High impact strength. Good damping behavior. Good abrasion resistance |
| Processing | Injection molding |
| Applications | Mechanical, automotive and apparatus engineering, e.g., for plain gearings, gear wheels, sliding plates |
NETZSCH Measurement
| Instrument | DSC 204 F1 Phoenix® |
| Sample Mass | 10.15 mg |
| Isothermal Phase | 5 min |
| Heating/Colling Rates | 10 K/min |
| Crucible | Al, pierced lid |
| Atmosphere | N2 (50 ml/min) |
Evaluation
As a semi-crystalline thermoplastic, PA6.6 showed a glass transition at 68°C (midpoint) in the 2nd heating (red) and an endothermal melting range from approx. 200°C to 270°C. As is often the case for PA6.6, a second melting transition at 250°C can be observed as a pre-peak (or shoulder) prior to the actual main melting effect with a peak temperature of 261°C. In the 1st heating (blue), post-crystallization (exothermal eff ect at 237°C) occurred prior to the melting peak. The corresponding glass transition temperature in the 1st heating at 54°C (midpoint) is lower than the Tg at 68°C in the 2nd heating due to the presence of a small amount of water, as evidenced by the shallow evaporation peak between 100°C and 200°C (blue curve).