Closing the loop: upcycling recycled carbon fibres as Joule heating elements for energy efficient composite tooling

The widespread deployment of high-performance composites across various industries, while beneficial, has led to an inevitable increase in composite waste and intensified concerns over resource and energy efficiency, challenging efforts toward sustainable manufacturing and circular material use. Although recycling efforts have successfully reclaimed valuable materials like recycled carbon fibres (rCF), effectively utilising these materials in value-added applications remains challenging. This study introduces a sustainable upcycling strategy that utilises rCF as energy-efficient heating elements integrated into composite tooling. Designed for enhanced thermal insulation and mechanical robustness, the developed tooling successfully cures carbon fibre/epoxy laminates with comparable properties to oven-cured specimens, while achieving a 90% reduction in energy consumption compared to traditional oven-based processes. A comparative, screening-level life cycle assessment (LCA) demonstrates its environmental benefits over traditional metal counterparts, with a 70% reduction in climate impact (40 vs. 140 kg CO 2 eq. per functional unit), highlighting its potential to significantly mitigate environmental impact of the composites manufacturing sector. The simple integration of upcycled rCF as an energy-efficient heating element provides a pathway toward more sustainable composite manufacturing.