Polyamide (Nylon)

Polyamide, commonly known as nylon, is a strong, versatile thermoplastic prized in aviation for its wear resistance and toughness.

Background and Evolution

Nylon was invented by Wallace Carothers at DuPont in 1935, entering commercial use by the late 1930s. Its aviation debut came during World War II in aircraft like the P-51 Mustang, replacing metal in gears and bushings. In commercial aviation, it gained traction in planes like the Boeing 727, remaining vital in modern designs such as the Airbus A350.

How Polyamide (Nylon) is Used

• Bushings and Bearings: Forms low-friction components in landing gear and control systems, reducing wear.
• Fasteners: Shapes clips, brackets, and cable ties, securing wiring and panels.
• Gears: Used in actuators and small mechanical systems, offering strength and durability.
• Interior Components: Constructs seat parts and trim, resisting abrasion and stress.

Why Polyamide (Nylon) is Used

• High Strength: Tensile strength (~70–100 MPa) supports load-bearing parts without metal’s weight.
• Wear Resistance: Self-lubricating properties extend lifespan in moving components.
• Lightweight: At 1.13–1.15 g/cm³, reduces aircraft mass compared to metals.
• Flexibility: Absorbs vibration and minor impacts, enhancing durability in dynamic systems.

• Chemical Resistance: Withstands fuels, oils, and cleaning agents, maintaining integrity.

Technical Specifications

• Density: 1.13–1.15 g/cm³, lighter than most plastics.
• Melting Point: ~220–265°C (e.g., Nylon 6 or 6,6), limiting high-heat use.
• Hardness: 70–80 Rockwell R, tough yet machinable.
• Moisture Absorption: 2–3%, affecting dimensions in humid conditions.

Comparison to Alternative Materials

• ABS: Easier to mold and cheaper, but less wear-resistant and strong.
• PTFE: Lower friction and heat-resistant, but softer and costlier.
• PEEK: Stronger and more heat-tolerant, though significantly pricier.
• Steel: Far stronger and durable, but heavier (7.8 g/cm³) and prone to corrosion.

Nylon excels in strength and wear for lightweight roles.

Role in Modern Aviation

In aircraft like the Boeing 737 and Airbus A320, nylon supports bushings, fasteners, and interior parts, reducing maintenance and weight. It complements PEEK in high-heat zones and ABS in moldable fittings, as seen in the Boeing 787 Dreamliner.

Environmental and Economic Considerations

• Production: Moderate energy use, with recyclable potential.
• Cost: Affordable compared to high-performance plastics like PEEK.
• Recycling: Reprocessable, though aviation-grade blends may limit reuse.

Future Trends

Reinforced nylon with glass or carbon fibers could boost its structural use, though advanced thermoplastics may reduce its scope in premium applications.

Summary

Nylon’s strength, wear resistance, and lightweight nature make it a key plastic in aviation’s mechanical and interior components. Since the 1940s, it has delivered reliable performance, holding a practical role amid evolving materials.