PA66: Polyamide 66

Short Name
Polyamide 66
ETP - Engineering Thermoplastics
General Properties
Chemical Formula
Structural Formula


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)
1.13 to 1.16 g/cm³
Semi-crystalline thermoplastic
General properties
Good mechanical strength. High impact strength. Good damping behavior. Good abrasion resistance
Injection molding
Mechanical, automotive and apparatus engineering, e.g., for plain gearings, gear wheels, sliding plates

Internet Links

NETZSCH Measurements

DSC 204 F1 Phoenix®
Sample Mass
10.15 mg
Isothermal Phase
5 min
Heating/Colling Rates
10 K/min
Al, pierced
N2 (50 ml/min)


As a semi-crystalline thermoplastic, PA6.6 showed a glass transition at 68°C (midpoint) in the 2nd heating (green) 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 effect 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).

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