Polysulfone (PSU)

Polysulfone (PSU), a high-performance thermoplastic, is valued in aviation for its heat resistance and optical clarity.

Background and Evolution

PSU was developed in the 1960s by Union Carbide, entering commercial use by 1965. Its aviation adoption began with aircraft like the Boeing 727, enhancing galley parts and panels due to its durability. It remains significant in modern planes like the Airbus A380, appreciated for its robust properties.

How Polysulfone is Used

PSU, a rigid amber plastic, is molded into:

• Galley Components: Forms trays, coffee makers, and oven parts, withstanding heat.
• Interior Panels: Shapes transparent dividers and light covers, aiding visibility.
• Electrical Housings: Used in connector shells and insulators, resisting thermal stress.
• Ventilation Ducts: Constructs lightweight air channels, enduring cabin conditions.

Why Polysulfone is Used

• Heat Resistance: Operates up to 170°C continuously, ideal for galley and electrical zones.
• Optical Clarity: Transmits ~80% light, perfect for visible panels, meets FAA flammability standards (e.g., FAR 25.853).

• Strength: Delivers tensile strength (~70–85 MPa), supporting moderate loads.
• Lightweight: At 1.24 g/cm³, reduces mass compared to metals, enhancing efficiency.
• Chemical Stability: Resists detergents and oils, suited for cabin use.

Technical Specifications

• Density: 1.24 g/cm³, lighter than PEI.
• Glass Transition: ~190°C, robust for moderate heat.
• Hardness: 80–90 Rockwell R, tough and durable.
• Impact Strength: ~60–70 J/m, resilient for light duty.

Comparison to Alternative Materials

• PEI: Stronger and more flame-resistant, but less transparent.
• Polycarbonate: Clearer and cheaper, but less heat-tolerant.
• PPS: Higher heat resistance, but opaque and less versatile.
• Acrylic: Lighter and clearer, but softer and less durable.

PSU excels in heat and transparency.

Role in Modern Aviation

In aircraft like the Boeing 737 and Airbus A320, PSU enhances galley parts, panels, and insulators, balancing strength and clarity. It works with PEI for durability and polycarbonate for visibility, improving function in models like the Airbus A380.

Environmental and Economic Considerations

• Production: Moderate energy use, with higher material costs.
• Cost: More expensive than PP, offset by performance.
• Recycling: Reprocessable, though aviation additives may limit reuse.

Future Trends

Reinforced PSU or cost-effective blends could broaden its use, though PEI may overshadow it in high-performance roles.

Summary

PSU’s heat resistance, clarity, and strength make it crucial for aviation’s galley and interior components. From its 1960s debut, it has delivered reliable performance, holding a specialized niche.