Aeronautical structures optimised with graphene-based materials
Decreasing fuel consumption and CO2 emissions of aircraft are crucial for increased efficiency and adherence to the EU’s Climate Law and carbon neutrality by 2050. Traditional aircraft production involves designing functional components separately and then integrating them into the structure. More ideal, however, would be to adopt an advanced integrative manufacturing approach involving fewer but more complex parts with multiple functions. This strategy would lead to more enhanced aerodynamic efficiency, as well as a decrease in aicraft weight. The GRAPHICING project coordinated by the Centre for Electrochemistry and Surface Technology – CEST GmbH in Austria, made significant advances in the bid to reduce the aircraft weight. Their innovation: advanced functional lightweight materials based on graphene-related materials (GRMs).
Cost-effective graphene production is the future
A commonly found mineral, graphite is a stable allotrope of carbon often used in the aeronautical industry. Graphene, a single carbon sheet of graphite, is one of the strongest materials ever tested. It is also advantageous due to its high conductivity, low density, and high surface area. A challenge in using graphene-based materials, however, is the high cost of production. The GRAPHICING project has developed an innovative cost-effective electrochemical process that efficiently produces large amounts of graphene-oxide flakes, for around EUR 500\kg at laboratory scale. These flakes are then adapted for various functionalities such as de-icing and fire retardation and integrated into a polymer composite matrix.
Environmentally friendly manufacture of graphene-based materials
Working within the Smart, Green and Integrated Transport programme, environmentally friendly manufacturing was a high priority for GRAPHICING researchers. For one, the electrochemical production of graphene-oxide utilises two non-toxic chemicals in combination with electricity. Jürgen Schodl, project coordinator and senior researcher at CEST, notes: “Furthermore, the graphene-based materials can be introduced into the polymer matrix via purely mechanical processes, and the composite materials can be produced via corresponding lamination processes – completely without environmentally harmful solvents.” A few challenges arose in the green-chemistry implementation of GRM into the polymer matrix. For example, mechanical and solvent-assisted methods failed to achieve enough conductivity for targeted functionalities. However, GRAPHICING researchers overcame this by switching to spray-coating.
Multifunctional aeronautic composite structure
Schodl points out: “The most important results of this project are, firstly, that four targeted functionalities of de-icing, lightning strike protection, water absorption barrier and flame inhibition can be achieved with the graphene-based materials. Moreover, they are obtained using a cost-effective and environmentally friendly electrochemical manufacturing process and subsequent chemical modification.” These results were achieved by improving on state-of-the-art technologies which comprise multiple parts as well as non-polymers alongside the graphite-containing polymers. Both can result in diminished mechanical properties required for, for example, prevention of in-flight icing. GRAPHICING overcame current limitations by incorporating graphene-based materials into a functional composite structure. The resulting integrated polymer matrix is lighter and more efficient than the state-of-the-art. Project researchers demonstrated the four targeted functionalities using small-scale prototypes. Next steps in the graphene-based future include larger scale prototypes and implementation into composite production technologies. Researchers are also improving the graphene-based materials and the production process. With their low weight and environmentally friendly production, graphene-based structures are essential to sustainable aeronautical transport.
Keywords
GRAPHICING, graphene, graphene-related materials, GRM, de-icing, aeronautical structures, electrochemical production
