If material researchers and engineers had a favourite material, carbon fibres are probably it. Why? Because they are light-weight but extremely sturdy. Motor and wind energy industry as well as space, aviation and naval industries are already using the composite material for their lightweight constructions and applications. However, thus far the versatile material is still petrol-based. This not only translates to an expensive manufacturing process, but also requires large amounts of resources and is simply not sustainable.

Cheap and sustainable carbon fibres made from lignin

Hence, Muhannad Al Aiti, a young researcher at the Technical University Dresden and the Leibniz Institute of Polymer Research Dresden (IPF), is investigating how carbon fibres could be manufactured from renewable resources. The idea to use biological waste products is not new, researchers have been investigating this approach for more than 60 years. And lignin had been at the top of possible bio-based materials for the last 20 years. Now, Al Aiti appears to have found a way to build sustainable carbon fibres from lignin.

Lignin is one of the main components of plant cells. Especially in woody (ligneous) plants, lignin provides stability. For the paper industry, however, lignin is a waste product and thus available for further processing cheap and in large quantities. “Every year, the paper industry accumulates about 50 million tons of lignin that are simply burnt,” says Al Aiti.  

New set of criteria for efficient production

Until now the purification of lignin has been relatively complicated and expensive, which has prevented previous lignin-based carbon fibres to enter the market. Therefore Al Aiti has looked at every step of the production process and provided a comprehensive list of criteria that tells researchers and industry partners whether their approach to a sustainable carbon fibre is financially sound. Part of his results are already published by Al Aiti and his colleagues, for instance in the renowned journal “Progress in Materials Science”.  

International collaborations ahead

The publication was met with great interest internationally and has led to a proposal for an EU-wide collaboration. Starting in mid-August, Al Aiti will be investigating the manufacturing process of the sustainable high-tech fibre at the Technical University Tampere in Finland. Only there he can produce the lignin-based carbon fibres in a  special spinning process. The goal: the process to isolate and purify lignin should be developed until industry-ready and able to produce stable, cheap and compatible bio-based carbon fibres.

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