Recyclable Hierarchical Composites: A Novel Route to Orientation Preserved Carbon Fibre Recovery
Source: BAM
Carbon fibre reinforced plastics (CFRP) are increasingly being used in wind turbine rotor blades because they combine high stiffness with low weight. This makes it possible to produce longer, lighter blades that can capture more energy from the stronger winds found at higher altitudes. As the use of these composite materials grows, so does the need for sustainable solutions at the end of their service life. Recycling is particularly important, as manufacturing carbon fibres is extremely energy and cost intensive, whereas recovering them requires only a fraction of that effort.
One major limitation of current recycling methods is that the recovered fibres are short, separate and randomly oriented. Since fibre alignment plays a critical role in determining the strength of composite materials, these recycled fibres are unsuitable for high performance applications such as rotor blades. To enable a true circular economy, recycling processes are therefore needed that preserve both fibre length and alignment.
Researchers from the division Polymer Composite Materials – Dr. C. Rodricks, Dr. G. Kalinka and Prof. V. Trappe – have developed a new approach in which carbon fibres remain aligned and undamaged even after several recycling cycles. In this method, aligned carbon fibres are first produced industrially and cost effectively, for example by pultrusion, as tapes, using a non-recyclable epoxy resin. These tapes are then bonded together into larger structures using a soluble, recyclable secondary matrix. In the present study, Elium© was used – a recyclable PMMA based polymer with properties comparable to those of epoxy resins. During recycling, the Elium matrix can be chemically dissolved, allowing the tape units to be fully recovered while preserving their original fibre structure.
The concept was tested over three recycling cycles. The recycled laminates retained around 60-90% of the load bearing capacity of conventional CFRP epoxy laminates, underlining the promise of this approach. As a proof of concept, there is still scope for further optimisation, for example by refining the geometry, surface treatment, and drying and curing conditions. Such improvements could enhance mechanical performance while maintaining full recyclability. Overall, the study demonstrates a viable route towards more sustainable high performance composite materials, supporting both environmental and economic goals through reduced waste and more efficient use of resources.
Novel Recyclable Hierarchical Carbon Fiber/Epoxy Composites: Preserving Fiber Length and Orientation Using Elium
Carol Winnifred Rodricks, Annabell Prockat, Gerhard Kalinka, Volker Trappe
Polymer Composites, 2026