Electrical pulse harvests more carbon fibres

A group of Japanese researchers is advancing carbon fibres recycling technology.

Academics of Waseda University are pioneering a ‘direct discharge electrical pulse method’ that recycles carbon fibre-reinforced polymers (CFRPs) in what is said to be an eco-friendly and efficient manner. The breakthrough yields high-quality carbon fibre and sets new benchmark technology.

CFRPs are typically used for applications when high strength-to-weight rations and stiffness are required, such as in aerospace, automotive or for sports equipment.

Shock waves

‘In our previous studies, we established expertise in generating shock waves in water using electrical pulse phenomena to efficiently fragment difficult-to-process materials,’ says Chiharu Tokoro, who leads the study.

‘However, in applications such as lithium-ion batteries, we discovered that direct discharge is more effective for high-efficiency separation than relying on shock waves. It uses joule heating, thermal stress and vapour expansion of the material itself.’

Tokoro’s R&D crew applied this approach to carbon fibre scrap, with ‘promising’ results. It preserves relatively longer fibres with higher tensile strength. The new technique also precisely separates target material into individual fibres without retaining any residual resin on the surface.

Wide application

Furthermore, the direct discharge approach reportedly improves energy efficiency by a factor of at least 10 compared to traditional alternatives. An added benefit is that there is no need for harsh chemicals or high temperatures.

Tokoro’s team believes the breakthrough may also boost recycling results for aircraft components, automotive waste and wind turbine blades. The findings have been published in Scientific Reports.