Bodaghi M., Mugemana C., Ozyigit S., Bayreuther C.G., Klein S., Moumen A.E., Macieira D., Lu M., Kerschbaum M.
Composites Part A Applied Science and Manufacturing, vol. 208, art. no. 109924, 2026
The increasing use of carbon fibre reinforced polymers (CFRPs) in high-performance applications raises critical challenges related to end-of-life management and material circularity. Although several recycling methods have been proposed, most recovered fibres are short or damaged, limiting their reuse in structural composite manufacturing processes such as filament winding. This study investigates the recovery and reuse of continuous carbon fibres from filament-wound thermoset composites using a cleavable thermoset resin system. Carbon fibre/epoxy tubes were manufactured via filament winding using both a conventional epoxy system and a cleavable epoxy resin. End-of-life composite structures were then subjected to a low-temperature chemical recycling process to recover continuous carbon fibres, which were subsequently re-impregnated and reprocessed into new filament-wound tubes. The recovered fibres and remanufactured composites were characterised through a multi-scale experimental approach including scanning electron microscopy (SEM), Raman spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), single-fibre tensile testing, micro-computed tomography (µCT), and mechanical testing of composite structures. Results show that the recycling process preserves most of the intrinsic fibre properties, with approximately 92% tensile strength retention compared with virgin fibres. Remanufactured tubes produced with recycled fibres exhibited a hoop tensile strength of approximately 1240 MPa, corresponding to a reduction of about 25–44% relative to reference tubes manufactured with virgin fibres. This performance decrease is primarily attributed to the removal of fibre sizing and partial degradation of the fibre–matrix interface during the recycling process. The results demonstrate the feasibility of recovering continuous carbon fibres from filament-wound thermoset composites and reintroducing them into filament winding manufacturing. While recycled fibres may not yet meet the requirements for primary load-bearing pressure vessels, they present significant potential for secondary structural applications. This work contributes to advancing circular composite manufacturing by demonstrating a viable route for closed-loop recycling of filament-wound CFRP structures.
