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About the difference between PA6, PA66 and PA12 nylon materials


Polyamide is commonly known as Nylon, and its English name is Polyamide (PA for short). It is a general term for thermoplastic resins containing repeating amide groups - [NHCO] - on the main chain of the molecule, including aliphatic PA, aliphatic-aromatic PA and aromatic PA. . Among them, aliphatic PA has many varieties, large output, and wide application. Its name is determined by the specific number of carbon atoms of the synthetic monomer. It was invented by the famous American chemist Carothers and his scientific research team.

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PA6 (Polyamide 6), PA66 (Polyamide 66), and PA12 (Polyamide 12) are all types of nylon, which is a class of polymers known as polyamides. They have differences in their molecular structures, properties, and applications. Here's a summary of the distinctions:

1.Molecular Structure:

  • PA6: Composed of repeating units of 6 carbon atoms.

  • PA66: Composed of repeating units of 6 carbon atoms and 6 nitrogen atoms.

  • PA12: Composed of repeating units of 12 carbon atoms.

2.Melting Point:

  • PA6: Typically has a melting point in the range of 215-225 degrees Celsius.

  • PA66: Generally has a higher melting point, around 260-270 degrees Celsius.

  • PA12: Has a lower melting point compared to PA6 and PA66.

3.Mechanical Properties:

  • PA6: Exhibits good toughness and impact resistance. It has lower strength and stiffness compared to PA66.

  • PA66: Known for higher strength, stiffness, and better heat resistance compared to PA6.

  • PA12: Often possesses good impact resistance and flexibility, making it suitable for certain applications.

4.Water Absorption:

  • PA6: Tends to absorb more moisture compared to PA66 and PA12. The absorption of moisture can affect its mechanical properties.

  • PA66: Exhibits lower water absorption than PA6.

  • PA12: Generally has lower water absorption compared to both PA6 and PA66.

5.Thermal Stability:

  • PA6: Shows good thermal stability, but it may be lower compared to PA66.

  • PA66: Offers better thermal stability, making it suitable for applications requiring high-temperature resistance.

  • PA12: Has moderate thermal stability.


  • PA6: Commonly used in automotive parts, consumer goods, and various industrial applications.

  • PA66: Widely used in automotive components, electrical and electronic parts, and structural components requiring high mechanical strength.

  • PA12: Often utilized in applications such as flexible tubing, oil and gas pipes, and certain automotive components.

The choice between PA6, PA66, and PA12 depends on the specific requirements of the application, including mechanical properties, thermal resistance, water absorption, and cost considerations. Each type of nylon has its advantages and is selected based on the desired performance characteristics for a given application.