Researchers Use Biotechnology to Recycle Carbon Fibre

Researchers at the Hohenstein Institute in Germany are studying a new way of recycling carbon fibres using biotechnology.

Trials at the Hohenstein Institute have shown how biotechnology can be used to create new ways of recycling carbon fibres. Researchers in the team led by Christin Glöckner are using microbiological systems to bring about the controlled breakdown of the synthetic matrix.

Even though manufacturing with composites can be very expensive, every year around 3000 tonnes of carbon fibre waste is generated in Europe alone, an enormous waste of such a valuable raw material as carbon fibres. The institute say that the recycling process currently being used to predominantly recycle carbon fibre is extremely energy-intensive and only short-staple carbon fibres can be recovered. Furthermore, the chemical and mechanical recycling methods that are known about today are very labour-intensive.

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The researchers at the Hohenstein Institute would like to develop a promising new alternative solution based on biotechnological recycling. They are making use of the fact that certain microorganisms are able to metabolise chemical substances, such as polyether resin, by biochemical processes.

By selecting suitable microorganisms, the researchers have managed to break down the plastic matrix of CFRPs, which is normally made of epoxy resin. This means that the plastic matrix can be broken down microbiologically and returned to the materials cycle as a metabolite. At the same time, the carbon fibres are extracted without damaging them so that they can be reclaimed for use in new products.

At the specialist conference on “Composite Recycling” earlier this year in Stuttgart, the first meeting of leading CFRP producers, manufacturers and recyclers was held, at which the main focus was on introducing recycling methods for reclaiming valuable carbon fibres. New ideas and solutions for “Composite Recycling” were presented and aspects of eco-balancing (energy efficiency, reduced emissions, costs) were discussed.

At the event It was agreed that in future there will be more and more end-of-life products which should go on to be recycled, but the search for alternative and sustainable solutions is not yet over. Following on from recycling, new strategies for using recycled fibres were also presented at the Stuttgart conference, such as the wet laid process used in carbon fibre paper manufacture and the extrusion of short-staple fibres in a polyamide filament matrix.