Polycarbonate (PC)

Polycarbonate (PC), a durable and transparent thermoplastic, excels in aviation for its toughness and lightweight characteristics.

Background and Evolution

Polycarbonate emerged in 1953, developed simultaneously by Bayer’s Hermann Schnell and GE’s Daniel Fox, hitting markets by the late 1950s. Its aviation journey started in the 1960s with planes like the Boeing 727, replacing glass in windows and fittings. It solidified its role in modern aircraft like the Airbus A380, prized for its resilience and versatility.

How Polycarbonate is Used

• Passenger Windows: Builds outer or secondary panes, ensuring clarity and impact protection.
• Interior Components: Crafts tray tables, seat backs, and overhead bins, offering strength and design flexibility.
• Lighting Covers: Shapes diffusers for cabin and navigation lights, managing light distribution.
• Protective Shields: Forms covers for sensors or minor displays, resisting damage.

Why Polycarbonate is Used

• Superior Toughness: Endures impacts 200 times stronger than glass, preventing shattering in collisions.
• Lightweight: With a density of 1.2 g/cm³, cuts weight significantly compared to glass, boosting efficiency.
• Transparency: Achieves ~90% light transmission, ideal for windows and optical uses.
• Thermal Stability: Handles temperatures up to 120°C, fitting moderate heat zones.

• Ease of Processing: Readily molded or extruded, streamlining production of complex parts.

Technical Specifications

• Density: 1.2 g/cm³, lighter than glass or metals.
• Softening Point: ~147°C, constraining high-temperature use.
• Hardness: 70–80 Rockwell R, balancing durability and workability.
• Impact Strength: ~600–850 J/m (unnotched), far outpacing acrylic.

Comparison to Alternative Materials

• Acrylic Glass: Slightly lighter (1.19 g/cm³) and clearer, but less robust.
• ABS: More affordable and moldable, yet weaker and opaque.
• Nylon: Stronger in wear, but less transparent and heat-sensitive.
• Tempered Glass: Harder and heat-tolerant, but heavier (2.5 g/cm³) and brittle.

Polycarbonate stands out for impact resistance and weight.

Role in Modern Aviation

In aircraft like the Boeing 737 and Airbus A350, polycarbonate is key in windows, interior fittings, and lighting, enhancing safety and reducing mass. It pairs with acrylic for clarity and ABS for cost-effective interiors, as seen in the Boeing 787 Dreamliner.

Environmental and Economic Considerations

• Production: Requires moderate energy, with scalable manufacturing keeping costs in check.
• Cost: Pricier than ABS, but competitive for its benefits.

• Recycling: Reprocessable into new PC, though aviation additives can hinder reuse.

Future Trends

Scratch-resistant coatings or flame-retardant blends may widen its scope, though advanced composites could reduce its interior use as weight demands rise.

Summary

Polycarbonate’s toughness, lightweight build, and clarity make it a cornerstone plastic in aviation’s windows, fittings, and lights. Since the 1960s, it has bolstered safety and performance, holding firm among evolving materials.