Polyethylene Terephthalate (PET)

Polyethylene Terephthalate (PET), a lightweight and durable thermoplastic polyester, is employed in aviation for its strength and recyclability.

Background and Evolution

PET was patented in 1941 by John Rex Whinfield and James Tennant Dickson at the Calico Printers’ Association, entering widespread use by the 1950s. Its aviation introduction came in the 1970s with aircraft like the Boeing 747, initially for disposable galley items, expanding to structural roles with fiber reinforcement in modern planes like the Airbus A320 due to its adaptability.

How Polyethylene Terephthalate is Used

• Galley Disposables: Shapes cups, trays, and food containers, providing lightweight utility.
• Interior Trim: Forms seat covers, upholstery films, and decorative laminates, enhancing aesthetics.
• Structural Components: Reinforces minor composite parts like brackets or panels, often as woven PET fibers (e.g., Dacron).
• Packaging: Used in cargo liners or protective wraps, resisting tears and moisture.

Why Polyethylene Terephthalate is Used

• Lightweight: At 1.38 g/cm³, reduces weight in non-critical applications, aiding fuel efficiency.
• Strength: Offers tensile strength (~60–80 MPa), sufficient for secondary structural roles.
• Recyclability: Easily reprocessed into new PET, aligning with sustainability goals.
• Chemical Resistance: Withstands cabin spills, cleaning agents, and moisture, maintaining integrity in passenger areas.

• Cost-Effectiveness: Inexpensive to produce, ideal for disposable and mass-produced items.

Technical Specifications

• Density: 1.38 g/cm³, comparable to PVC.
• Melting Point: ~250–260°C, suitable for moderate heat exposure.
• Hardness: ~80 Rockwell R, durable for light-duty roles.
• Elongation: 50–300%, flexible yet strong.

Comparison to Alternative Materials

• Polycarbonate: Tougher and clearer, but costlier and less recyclable.
• ABS: Stronger and more impact-resistant, though less flexible and transparent.
• PVC: Similar weight and cost, but less recyclable and heat-sensitive.
• Acrylic: Clearer and lighter, but less durable and flexible.

PET balances cost, weight, and eco-friendliness.

Role in Modern Aviation

In aircraft like the Boeing 737 and Airbus A350, PET dominates galley disposables and interior trim, with minor use in composites. It complements polycarbonate in durable fittings and ABS in structural interiors, as seen in the Boeing 787 Dreamliner.

Environmental and Economic Considerations

• Production: Moderate energy use, with low raw material costs.
• Cost: Among the cheapest plastics, scalable for wide use.
• Recycling: Highly recyclable, with ~60% of PET reused globally, reducing waste.

Future Trends

Advanced recycling techniques or reinforced PET fibers could expand its structural role, though sustainable alternatives like PLA may challenge its dominance as environmental priorities sharpen.

Summary

PET’s lightweight strength, recyclability, and affordability make it a versatile plastic in aviation’s galley, trim, and minor components. Since the 1970s, it has supported efficiency and eco-conscious design, retaining utility among advanced materials.