Spotlight June 2023: New catalytic process for recovering important materials from composites in a single process

Previously virtually impossible and a huge problem: fibre-reinforced resin composites (epoxides) were not recyclable, and wind turbine rotor blades, for example, add up to a waste pile of 43 million tons by 2050. Researchers have now taken an important first step in “reprocessing” these composites and catalytically dissolving them so that the carbon fibres and resin ingredients can be separated without harming the materials. The process is not limited to rotor blades but can be applied to all composite materials. Particularly, because of the recovery of the expensive carbon fibres, this method is worthy of attention and leads to a better circular economy, thus, to improved sustainability.

Composite materials based on synthetic resins, usually reinforced with carbon fibres, are designed for long durability and are therefore fundamentally difficult to degrade. Until now, they have been stored as waste in landfills and thus removed from the cycle of materials.

Scientists at Aarhus University and the Danish Technological Institute have now filed a patent application for a process that, based on a catalyst containing ruthenium and various solvents, can break down the epoxy matrix and expose the carbon fibres without damaging them. The ingredients bisphenol A and the glass or carbon fibres are recovered and can be reused.

However, ruthenium is a rare and expensive metal, and the efficiency of the process has not yet been scaled-up to industrial level, but it is more than a glimmer of hope on the road to full recovery of the highly stable composites.

Original publication:

Ahrens, A et al. (2023). Catalytic disconnection of C-O bonds in epoxy resins and composites. Nature, 617, 730–737