Why PA66 and PA6 Perform Differently (Hydrogen Bonding Effect

The performance differences between PA66 and PA6 are largely due to hydrogen bonding within the polymer structure. PA66 has a higher concentration of amide groups per unit length compared to PA6, resulting in more hydrogen bonds between molecular chains. This leads to stronger intermolecular forces in PA66.

Consequences of stronger hydrogen bonding in PA66:

• Higher thermal properties (hence higher processing temperatures and higher melting point)
• Greater rigidity and stiffness
• Lower water absorption rate (the denser structure reduces moisture ingress)
• Consequences for PA6:
• Better toughness and impact resistance (more ductile)
• Faster moisture absorption rate
• Lower melting point and easier processing at lower temperatures