Thermal behavior of Akulon® and Akulon® Ultraflow®

Akulon polyamides perform over a wide temperature range. Unfilled and reinforced materials can be used for demanding engineering applications from as low as -40°C (-40°F) to just below the melting point of the polymer, 220°C (428°F) in case of PA6 and 260°C (500°F) for PA66.

General temperature characteristics of Akulon
For all characteristics except melting point, actual values depend on grade concerned.

• Melting point
   PA6 220°C (428°F)
   PA66 260°C (500°F)
• Heat Distortion Temperature
  Unfilled      
   PA6 85°C   (185°F)                      
   PA66 100°C  (212°F)
  Mineral filled  
   PA6 185°C  (365°F)                      
   PA66 215°C  (419°F)
  Glass filled    
   PA6 210°C  (410°F)                      
   PA66 255°C  (491°F)
• Continuous Use Temperature
   PA6  130 - 170°C  (338°F)
   PA66 130 - 150°C  (302°F)
• Relative Temperature Index (UL)
   PA6  150°C  (302°F)
   PA66  140°C  (284°F)
• UL Class 1446
   PA6     F
   PA66   F

Toughness increases as temperature increases and decreases as temperature drops. Stiffness and strength decrease as temperature rises. Below ambient conditions, values will increase. Up to 180°C (356°F) the strength and modulus of similar grades of PA6 and PA66 are very similar. Above 200°C (392°F), PA66 with its higher melting point exhibits however a clear advantage; note however, that not many applications are really exposed to these kind of extreme high temperatures.

The high crystallinity and melting point of Akulon enables these materials to retain stiffness at elevated temperatures. For critical applications, this ensures better safety margins and  allows for wall thickness reductions compared to other materials.

Stiffness versus temperature

Influence of temperature on properties – long term
With prolonged exposure to high temperatures, as with any polymer, oxidation will occur and performance will start to deteriorate. Oxidative stability is improved by the inclusion of heat stabilizers in the plastic compound.The type and amount of stabilizer determines the long term aging characteristics so that different types of Akulon can have different performance.

For applications operating continuously at high temperatures
Some test methods for heat aging characteristics measure residual properties at room temperature after heat aging (with or without applied loads during aging).

This does not give a reliable indication of performance at the operating temperatures. Properties after ageing should be measured at the operating conditions, ideally under real conditions in the application itself. For automotive applications where peak temperatures will not exceed 180°C (356°F), PA6 provides better heat aging resistance and greater security and durability than PA66.

Strength at 170°C after heat aging exposure.

Heat stabilized Akulon and Akulon Ultraflow grades
For automotive under-the-hood applications which are usually colored black, the most effective stabilizers are used. For electrical or other applications where light colors are required, an alternative package is used to give the most performance effective balance between colorability and stabilization.