Op-ed by Dr. Baris Kumru, assistant professor at Vidyasirimedhi Institute of Science and Technology (VISTEC-Energy Science and Engineering).
Aviation is no longer a luxury—it’s a necessity in our hyper-connected world. Whether for business, leisure, or logistics, air travel enables us to traverse continents in hours.
Behind this seamless mobility lies a quiet revolution in materials science: the widespread use of fibre-reinforced polymer composites. Compared to traditional metals like aluminium, these composites drastically reduce aircraft weight which directly translates into fuel savings and lower carbon emissions per passenger-kilometre.
In today’s modern aircraft, polymer composites make up more than 50% of structural components, including the fuselage, wings, empennage, and radome.
The secret behind their strength and lightness lies in their architecture: strong and stiff carbon fibres embedded in an epoxy resin matrix. Think of the epoxy as a pancake—initially a pourable liquid, it cures into a stable, irreversible solid by thermal treatment.
Through decades of innovation in design and certification, composite aerostructures have matured into industry-standard technology. But a hard truth remains: they are designed to last, not to come apart—and therein lies the sustainability challenge.
Is it a circular business?
When aviation companies showcase their environmental progress, the headlines often focus on alternative fuels: sustainable aviation fuel (SAF), hydrogen propulsion, or electrification. These innovations are indeed crucial.
However, what rarely enters the public spotlight is the end-of-life dilemma facing aerospace materials.
Composite structures, despite their energy efficiency in flight, are rarely recyclable. Once cured, thermoset polymer matrices resist reshaping or melting. When aircraft are decommissioned, these durable materials are mostly landfilled or, at best, incinerated, sharing a fate with wind turbine blades which use similar technologies.
Several efforts have emerged to address this. Pyrolysis and solvolysis can extract short carbon fibres from waste composites, and these can find second life in non-structural automotive or construction parts. However, these methods are energy-intensive, and they downgrade the fibre properties as well as preventing closed-loop recycling.
What this reveals is a structural contradiction: we’re applying circular economy principles to fuels, but not to the materials that form the aircraft itself. The consequence is a growing stockpile of highly engineered, high-carbon-footprint waste. If we can find ways to retain or recover the value of these materials, we not only reduce waste but also lessen our dependence on virgin petrochemical inputs.
From a performance perspective, carbon fibres remain irreplaceable. But the feedstock used to make them need not be fossil-based. Polyacrylonitrile (PAN), the standard precursor, is energy-intensive to produce. However, recent studies have shown promising routes to generate carbon fibres from renewable lignocellulosic biomass.
Additionally, polymer matrix can be engineered using renewable starting materials which possess similar properties to petroleum derived parts. If brought to scale, this could dramatically cut the embedded emissions of next-gen composite parts.
Meanwhile, several new frontlines are reshaping the sustainability landscape. High-performance thermoplastic composites offer another route. Unlike thermosets, thermoplastics can be reheated and reshaped multiple times. Their growing adoption suggests a future where structural parts could be manufactured, joined, disassembled, and reused more readily. However, their processing and raw materials still remain a significant hurdle towards sustainability.
Vitrimers are thermosetting polymers with dynamic covalent bonds. Unlike traditional thermosets, vitrimers can be reshaped or reprocessed with heat, while still maintaining excellent mechanical stability during use. This enables both repair and recycling while their composite manufacturing is compatible with current industrial standards.
Frontal polymerisation is an emerging technique that enables ultra-fast curing of thermosetting composites with minimal energy input. By localising the reaction zone and propagating it through the material like a flame front, this approach cuts down on manufacturing time and energy hence contributes to sustainable manufacturing of parts.
There is a global effort on sculpting sustainable aerostructures. While some technologies are still at low technology readiness level, their payoff at improved levels will be significant: a future in which high-performance materials no longer carry a high environmental cost.
About the author
Dr. Baris Kumru is an assistant professor at Vidyasirimedhi Institute of Science and Technology (VISTEC-Energy Science and Engineering) in Thailand and previously at Delft University of Technology (Faculty of Aerospace Engineering) in the Netherlands. He specialises in the design, synthesis, and application of circular aerospace materials, with a track record in both academic and industrial R&D. He frequently shares insights on sustainable materials for high-performance engineering and energy sectors.
