Polyamide vs Nylon: What's the Difference and Which One Should You Use?
Learn the difference between polyamide and nylon. Compare properties, applications, and machining behavior. Discover which material is best for your part or product.
Polyamide and nylon are often used interchangeably in engineering, textiles, and manufacturing—but they’re not exactly the same.
While all nylons are polyamides, not all polyamides are nylons. Understanding the differences between these two terms is key to choosing the right material for mechanical parts, consumer products, and industrial applications.
In this article, we’ll break down the chemistry, mechanical properties, use cases, and differences between polyamide and nylon, helping you select the best option for your next project.
What Is Polyamide?
Polyamide is a broad class of polymers characterized by repeating amide bonds (-CONH-) in their molecular chain.
Types of polyamides include:
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Aliphatic polyamides: Like Nylon 6, Nylon 66 (the most common)
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Aromatic polyamides (aramids): Like Kevlar® and Nomex®
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Bio-based polyamides: Derived from renewable sources (e.g., PA11, PA610)
Polyamides are known for their:
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High strength-to-weight ratio
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Chemical resistance
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Wear resistance and toughness
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Thermal stability
They can be either synthetic (like Nylon 6) or semi-synthetic (like castor oil-derived PA11).
What Is Nylon?
Nylon is a specific family within the broader polyamide category, originally developed by DuPont in 1935.
Nylons are typically aliphatic polyamides and are known for their versatility. Common types include:
| Nylon Type | Composition | Use Case |
|---|---|---|
| Nylon 6 | Made from caprolactam | Gears, bearings, industrial parts |
| Nylon 66 | Made from hexamethylene diamine and adipic acid | Automotive, textiles, fasteners |
| Nylon 12 | Low moisture absorption | Tubing, flexible connectors |
In short: nylon is a subtype of polyamide, but not all polyamides are nylons.
Key Differences Between Polyamide and Nylon
| Property | Polyamide (General) | Nylon (Subset) |
|---|---|---|
| Definition | Class of polymers with amide bonds | Specific synthetic polymers within polyamide group |
| Composition | Varies (aliphatic, aromatic) | Typically aliphatic (e.g., Nylon 6/66) |
| Mechanical Strength | Wide range depending on type | High tensile and impact strength |
| Moisture Absorption | Depends on polyamide grade | Nylon 6 and 66 absorb more moisture |
| Thermal Resistance | Aromatic types have higher temp tolerance | Moderate (~180–200°C for Nylon 66) |
| Flexibility | Varies by type | Nylon 12 more flexible; Nylon 66 more rigid |
| Applications | Broader, includes high-performance and bio-based variants | Common in engineering, textiles, automotive |
Mechanical and Thermal Properties
When comparing polyamide types (including nylons), it's important to understand their performance under stress, heat, and moisture.
| Property | Nylon 6 | Nylon 66 | Aramid (Kevlar) |
|---|---|---|---|
| Tensile Strength (MPa) | 80–90 | 90–100 | 3000+ (fiber form) |
| Flexural Modulus (MPa) | 2500–3000 | 3000–3500 | Very high |
| Heat Deflection Temp (°C) | ~180 | ~200 | ~370+ |
| Water Absorption (%) | ~2.5 | ~2.7 | Low |
| Wear Resistance | Good | Excellent | Exceptional |
Takeaway:
If you need heat or chemical resistance beyond what nylon offers, go with specialty polyamides like aramids or semi-aromatics.
Applications of Polyamide vs Nylon
Nylon Applications:
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Gears and bushings in mechanical assemblies
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Cable ties, clips, and fasteners in automotive and electrical fields
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Textiles and fibers in clothing and sports equipment
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Injection-molded parts for consumer products and enclosures
Polyamide Applications (Beyond Nylon):
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Kevlar (aramid): Bulletproof vests, aerospace components
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PA12 tubing: Flexible fuel lines, pneumatic hoses
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Bio-polyamides (PA11): Eco-friendly automotive connectors, electrical housings
Moisture Absorption and Dimensional Stability
One of the biggest challenges with nylons is moisture absorption.
Nylon 6 and 66 can absorb up to 2–3% of their weight in water, which can lead to dimensional changes and reduced mechanical strength in humid environments.
In contrast, polyamide variants like Nylon 12 or PA11 absorb much less moisture (0.3–0.6%), making them ideal for outdoor or high-humidity applications.
If your project requires dimensional stability over time, consider a lower-absorption polyamide.
CNC Machining Considerations
Both polyamide and nylon are well-suited for CNC machining, but each has different requirements.
Nylon (especially Nylon 6 or 66):
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Can warp due to internal stresses or moisture
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Requires sharp tools to reduce frictional heating
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Often machined with air cooling
Other Polyamides:
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PA12 and PA11: Easier to machine due to better dimensional stability
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Aramids (Kevlar): Very abrasive—require carbide or diamond tools
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Reinforced grades (with glass fibers): Tougher on tools but more rigid
For prototypes or short-run parts, choosing the correct grade ensures easier machining and better results. To explore machining services tailored to polymer performance, visit this polyamide vs nylon resource.
Polyamide vs Nylon in 3D Printing
Nylon is a go-to material in Selective Laser Sintering (SLS) and Fused Filament Fabrication (FFF).
Nylon 12 and PA11 are commonly used because of their low shrinkage, flexibility, and resistance to chemicals.
If you’re printing parts for functional use, PA12 and PA11 (both polyamides) offer better stability than Nylon 6.
Recommended Use:
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Nylon 12 or PA12: Best for strong, flexible parts
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Nylon 6/66: Better for rigid, cost-sensitive applications
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Aramids: Rarely used in 3D printing due to processing challenges
Which One Should You Choose?
Here’s a simplified selection guide:
| Requirement | Recommended Material |
|---|---|
| High tensile strength | Nylon 66 or Nylon 6 |
| Low moisture absorption | Nylon 12 or PA11 |
| Extreme heat or chemical resistance | Aromatic polyamides (e.g., Kevlar) |
| Eco-friendliness | Bio-based PA11 |
| Flexibility and toughness | Nylon 12 or PA6 blends |
| Abrasion and impact resistance | Nylon 66 or reinforced PA6 |
Final Thoughts
Polyamide and nylon are deeply related—but choosing the right material means understanding the differences.
Use nylon when you need general-purpose strength, flexibility, and affordability. Choose other polyamides when your application demands better chemical resistance, lower water absorption, or higher temperature performance.
Whether you're machining parts or producing components with SLS or MJF printing, choosing between polyamide and nylon starts with understanding their chemistry and how it affects your end use.
To make the right choice and learn how these materials perform in real-world machining, visit this in-depth comparison of polyamide vs nylon.
