PA66
Polyamide 66 (Nylon 66)
Glass Transition (Tg)
50–70 °C
Melting Point (Tm)
255–265 °C
Density
1.13–1.15 g/cm³
CAS Number
32131-17-2
Recycling Code
♺ 7
Category
Engineering
Repeat Unit
–[NH–(CH₂)₆–NH–CO–(CH₂)₄–CO]ₙ–
The repeating unit is the smallest structural fragment whose repetition builds the whole chain. Subscripts show the relative share of each unit in copolymers.
Key Properties
Higher melting point, stiffness and heat-deflection temperature than PA6 due to denser hydrogen bonding; narrower processing window.
Applications
Under-hood automotive parts, cable ties, carpet fibre, industrial ropes.