Recycled glass fibre‒epoxy composites based on recovered fabrics from an environment-friendly combined solvolysis and thermolysis route

Abstract

Material recycling is essential for environmental sustainability, but recycling composites remains notably more complex and costly than recycling metals. This study presents a novel eco-friendly and cost-effective route for recycling fibre-reinforced composites, capable of processing large-sized laminates. We decompose the amine-cured epoxy matrix of glass-fibre-reinforced laminates using hydrogen peroxide (35 wt% and 50 wt%, without co-oxidants or additives) at 90 °C and atmospheric pressure. The immersion time required is 24 hours for the 50 wt% concentration and 36 hours for the 35 wt% concentration. This decomposition route effectively breaks down the epoxy resin, enabling the recovery of woven fabric layers with unaltered architecture and satisfactorily clean glass fibres. Then, we use the recovered fabric layers to remanufacture composite panels. Microscopy and thermal degradation analyses reveal the characteristics of resin residues on the fibre surfaces, facilitating a comparison of the quality between virgin and recovered fibres. Fourier-transform infrared spectroscopy provides insights into the composition and recyclability of the decomposition products. Three-point bending tests and fractographic analysis assess the mechanical performance of the recycled composites. Finally, a preliminary life cycle assessment indicates the environmental viability of the process. Overall, the proposed decomposition method shows significant potential for recycling glass-fibre woven fabrics for reuse in moderate to high-performance structural applications.