Cyrene as a biobased solvent for the green delamination recycling of carbon fiber-reinforced polymer laminates

Abstract

The brittle and rigid nature of the resin matrix makes it difficult to cut carbon fiber-reinforced polymer (CFRP) laminates into thin slices and reprocess them into strongly oriented strand boards. To address this limitation, Cyrene, which is a biodegradable, non-toxicity biobased solvent, was employed to recycle CFRP laminates by inducing resin swelling. At 160–220 °C under atmospheric pressure, Cyrene fully swelled and softened the epoxy matrix within 30–240 min. The resin swelling rate ranged from 53.40 % to 303.39 %, with corresponding mass loss rates of 0–12.59 %. The resulting volume expansion led to delamination of the laminate into pliable monolayer carbon fiber (CF) sheets. These sheets were subsequently cut, dried, cross-stacked, and hot-pressed into new CFRP plates. The re-prepared laminates exhibited flexural, tensile, and interlaminar shear strengths ranging from 72.3 % to 77.5 %, 74.6 %–87.0 %, and 84.6 %–88.3 % of the original CFRP laminates. This mild process retained the CF length and mechanical performance while transferring waste resin into the new product. Cyrene, being thermally stable, was recovered by decompression distillation. This study offers a green and full-component recycling strategy for CFRP waste, supporting sustainable development through resource conservation and reuse.