PA66 (Nylon 66) vs PA6 (Nylon 6): Same polyamide family β PA66 is stiffer and more heat-resistant
PA66 (Nylon 66) vs PA6 (Nylon 6)
Side-by-side chemical composition and mechanical property comparison.
Overview
PA66 (Nylon 66)
Polyamide 66 β stiffer and more heat-resistant than PA6. Higher crystallinity gives better creep resistance and ~40Β°C higher melting point (260Β°C vs 220Β°C). Slightly more brittle. More moisture-sensitive at saturation than PA6. Trade names include Ultramid A (BASF), Zytel 101 (DuPont), Tecamid 66 (Ensinger). Dominant in US/UK markets. Used for automotive engine components, electrical connectors, gears, cable ties, and industrial bushings.
PA6 (Nylon 6)
Polyamide 6 (Nylon 6) β the most widely used engineering thermoplastic. Excellent combination of mechanical strength, toughness, wear resistance, and chemical resistance. Properties are moisture-sensitive β conditioned (50% RH) values are significantly lower than dry values. Trade names include Ultramid B (BASF), Akulon (DSM), Zytel (DuPont). Used for gears, bearings, bushings, cable ties, structural brackets, and automotive under-hood components.
| PA66 (Nylon 66) | PA6 (Nylon 6) | |
|---|---|---|
| Material Number | β | β |
| Category | Polymers | Polymers |
| Standard | ISO 10350 | ISO 10350 |
Chemical composition (wt%) β Pro
| Element | PA66 (Nylon 66) | PA6 (Nylon 6) | Overlap |
|---|---|---|---|
| Hexamethylenediamine unit | 45β55% | β | β |
| Adipic Acid unit | 45β55% | β | β |
| Polycaprolactam (from Ξ΅-caprolactam) | β | 99β99.9% | β |
Mechanical properties β Pro
| Property | PA66 (Nylon 66) | PA6 (Nylon 6) | Unit |
|---|---|---|---|
| Tensile Strength | 80β90 | 75β85 | MPa |
| Yield Strength | 80β85 | 70β80 | MPa |
| Elongation | 15β40 | 30β100 | % |
| Elastic Modulus | |||
| Density | |||
| Melting Point | |||
| Glass Transition Temp (Tg) | |||
| Water Absorption (24h) | |||
| Tensile Strength | |||
| Tensile Modulus | |||
| Elongation at Break | |||
| Charpy Impact (notched) | |||
| Density | |||
| Melting Point | |||
| Glass Transition Temp | |||
| Water Absorption (24h) | |||
| Water Absorption (saturation) |
Sign up free and get 3 full comparisons immediately.
Sign up free β 3 comparisons/day freeCompatibility Assessment
PA66 has ~40Β°C higher melting point (260 vs 220Β°C), higher stiffness (E-Mod 3.2 vs 2.9 GPa dry), and better creep resistance. PA6 is tougher (higher elongation), absorbs less moisture at saturation, and is cheaper. Choose PA66 for heat-critical parts (engine bay); PA6 for impact-loaded general purpose.
Frequently Asked Questions
Is PA66 (Nylon 66) the same as PA6 (Nylon 6)?
PA66 (Nylon 66) and PA6 (Nylon 6) have a 80% composition overlap. Same polyamide family β PA66 is stiffer and more heat-resistant
Can I replace PA66 (Nylon 66) with PA6 (Nylon 6)?
In many cases, yes. The compositions overlap significantly (80%). However, always verify mechanical property requirements and heat treatment compatibility for your specific application.
What is the difference between PA66 (Nylon 66) and PA6 (Nylon 6)?
The main differences are in the following elements: overall alloying content. PA66 (Nylon 66) is a Polymers grade, while PA6 (Nylon 6) is a Polymers grade.
Related Comparisons
View full data for each material:
Data provided for reference only. Always verify against the applicable specification for critical applications.
All data is for reference only. Equivalents indicate similarity, not identity. Always verify against the applicable specification for safety-critical applications. materialref.com accepts no liability for decisions based on this data.