Carbon fiber-reinforced plastics are gaining importance as components of aircraft. The trend is increasing the need for sustainable recycling concepts. At the ILA from April 25 to 29, 2018 in Berlin (Hall 2, Booth 304), Fraunhofer will present a technology that converts recycled carbon fibers into materials for batteries and fuel cells. This saves costs, improves the CO2 balance and opens up new means of recycling in aircraft production.
Modern wide-body aircrafts today consist of over 50 percent carbon fiber reinforced plastics (CFRP). The material is installed, for example, over a large area in the wings or fuselage. With carbon fibers embedded in a plastic matrix, the composite is lighter than previously used materials, while still being very stable. The decisive advantage for aviation: due to their lower weight, airplanes need less fuel.
"The manufacturing and processing of the CFRP is currently very time-consuming. The demand for sustainable recycling concepts is therefore steadily increasing," observes Elisa Seiler, scientist at the Fraunhofer Institute for Chemical Technology ICT in Pfinztal, Germany. The amounts of CFRP recycling material are tremendous: for the Airbus 350, for example, they add up to over 65 tons. "In addition to this there are other relevant scrap quantities that already arise during production," adds Seiler.
Bipolar plate manufactured
The Fraunhofer ICT has many years of experience in the development of technologies for fiber-reinforced plastics. At the ILA, the aviation and aerospace innovation trade fair, the scientists are presenting a concept that will be used to recover materials for batteries and fuel cells out of recycled carbon fibers. Together with partners, it has been possible to use recovered carbon fibers to produce a prototype of a bipolar plate – an electrode – on an industrial scale. The result is based on research from the "Graphit 2.0" and "RETRO" projects.
"Electric drives are now also a serious topic in the aviation industry. Manufacturers can directly perform value-preserving recycling by transferring materials from one application to the next," says Seiler. The carbon fibers are electrically conductive and are suitable as a substitute for natural graphite, which also consists of carbon: a resource-critical raw material for the German economy that currently has to be imported from China at great expense.
Food for 3D printing
Another advantage: recycled CFRP can be used for additive manufacturing processes such as 3D printing. "This is also a trending topic in the industry that makes production processes more efficient and saves costs," says Seiler. After all, aircraft manufacturers also have to comply with the European Union (EU) requirements that have been in force since 2015: up to 85 percent of the average weight of a used vehicle has to be recycled. In addition: In Germany, the landfilling of CFRP is prohibited, and waste incineration plants can refuse to accept the material.
Pyrolysis with microwave radiation
The CFRP experts have developed a special process with which carbon fibers can be recovered from the plastic matrix. To do so, they use microwave radiation to burn the plastic matrix that surrounds the fibers. So that the fibers do not burn up at temperatures of up to 900 degrees Celsius, the combustion has to be performed without oxygen.
"In technical jargon, this is called pyrolytic decomposition," Seiler explains. The advantage of microwave radiation: energy efficiency – a whole oven no longer needs to be heated, just the component itself. The colleagues of the Polymer Engineering department at the Fraunhofer ICT embed the recovered fibers in thermoplastic material. This composite material has similar properties to graphite and is suitable for the production of bipolar plates. "Our prototype passed all the tests for conductivity, density and corrosion resistance perfectly," reports Seiler.
"We’ve proven that it’s generally feasible to use recycled CFRP fibers to produce bipolar plates for batteries and fuel cells. This shows that recycling works in a holistic approach. This is particularly interesting for the aviation industry," says Seiler in summarizing the added value of the research work. Both the recycled CFRP as well as the bipolar plates made from it can be seen at the ILA.
The next steps until early summer are the characterization of the bipolar plates in the battery cell network and studies concerning the life cycle assessment. "Then, we want to tune the technology so that we can manufacture bipolar plates from recycled CFRP in series – for example, with an aviation partner," concludes Seiler.
Tobias Steinhäußer | Fraunhofer-Gesellschaft
Medica 2019: Arteriosclerosis - new technologies help to find proper catheters and location of vasoconstriction
11.11.2019 | Technische Universität Kaiserslautern
Laser versus weeds: LZH shows Farming 4.0 at the Agritechnica
08.11.2019 | Laser Zentrum Hannover e.V.
Using a clever technique that causes unruly crystals of iron selenide to snap into alignment, Rice University physicists have drawn a detailed map that reveals...
University of Texas and MIT researchers create virtual UAVs that can predict vehicle health, enable autonomous decision-making
In the not too distant future, we can expect to see our skies filled with unmanned aerial vehicles (UAVs) delivering packages, maybe even people, from location...
With ultracold chemistry, researchers get a first look at exactly what happens during a chemical reaction
The coldest chemical reaction in the known universe took place in what appears to be a chaotic mess of lasers. The appearance deceives: Deep within that...
Abnormal scarring is a serious threat resulting in non-healing chronic wounds or fibrosis. Scars form when fibroblasts, a type of cell of connective tissue, reach wounded skin and deposit plugs of extracellular matrix. Until today, the question about the exact anatomical origin of these fibroblasts has not been answered. In order to find potential ways of influencing the scarring process, the team of Dr. Yuval Rinkevich, Group Leader for Regenerative Biology at the Institute of Lung Biology and Disease at Helmholtz Zentrum München, aimed to finally find an answer. As it was already known that all scars derive from a fibroblast lineage expressing the Engrailed-1 gene - a lineage not only present in skin, but also in fascia - the researchers intentionally tried to understand whether or not fascia might be the origin of fibroblasts.
Fibroblasts kit - ready to heal wounds
Research from a leading international expert on the health of the Great Lakes suggests that the growing intensity and scale of pollution from plastics poses serious risks to human health and will continue to have profound consequences on the ecosystem.
In an article published this month in the Journal of Waste Resources and Recycling, Gail Krantzberg, a professor in the Booth School of Engineering Practice...
03.12.2019 | Event News
15.11.2019 | Event News
15.11.2019 | Event News
09.12.2019 | Earth Sciences
09.12.2019 | Information Technology
09.12.2019 | Life Sciences