Nylon (Polyamide)
Fundamental Properties
Nylon polymers feature repeating amide groups (-NHCO-) in their molecular chains, exhibiting:
• High Strength & Toughness: Intermolecular hydrogen bonds impart superior mechanical strength and toughness, ranking top among synthetic fibers.
• Wear Resistance & Self-Lubrication: Low coefficient of friction outperforms most engineering plastics.
• Chemical Resistance: Excellent resistance to oils, organic solvents, and most chemicals with outstanding corrosion resistance.
• Processability: Low melt viscosity and good flow enable versatile molding (injection, extrusion, etc.).
• Hygroscopicity: Polar amide groups cause significant moisture absorption, affecting dimensional stability.
Physical & Mechanical Properties
| Property | Typical Value/Feature | Application Impact |
| Tensile Strength | 60-80 MPa (unfilled) | Withstands heavy loads |
| Impact Resistance | Nylon 6 > Nylon 66 | Ideal for impact-critical parts |
| Hardness | Moderate, good machinability | Balances processability & durability |
| Wear Resistance | Low friction, self-lubricating | Gears, bearings, moving components |
| Density | 1.12-1.15 g/cm³ | Lightweight advantage |
| *Glass-fiber reinforced variants (e.g., 30% GF) increase tensile strength by >50% and significantly elevate HDT.* |
Chemical & Corrosion Resistance
• Acid Resistance: Stable in weak acids (pH 4-7); degrades in strong acids.
• Alkali Resistance: Resists weak alkalis (pH 8-10); limited tolerance to concentrated bases.
• Solvent Resistance: Withstands alcohols, gasoline; swells under prolonged immersion.
• Oil Resistance: Excellent for automotive fuel systems.
• Weatherability: Strong UV resistance for extended outdoor use.
Chemically modified grades (e.g., Nylon 66) exhibit enhanced corrosion resistance.
Thermal Properties by Type
| Nylon Type | Melting Point (°C) | Long-Term Use Temp (°C) | Key Feature |
| Nylon 6 | 215-220 | 80-120 | Broad processing window |
| Nylon 66 | 255-265 | 120-150 | Optimal heat resistance |
| Nylon 46 | 295 | 150-180 | High crystallinity |
| Nylon 6T | 310-325 | 180-200 | High-temp representative |
| Nylon 11 | 185 | 90-110 | Low-melt applications |
| *High-temperature nylons (e.g., PA6T) achieve HDT up to 280-305°C, surviving solder reflow (260°C).* |
Electrical Properties
• Insulation Resistance: Volume resistivity 10¹²-10¹⁵ Ω·cm (dry)
• Dielectric Strength: ~32 kV/mm (high breakdown voltage)
• Humidity Impact: Insulation declines when moist – still exceeds most plastics
• High-Frequency Limitation: Polar groups restrict high-frequency use