Mechanochemical Modification of Recycled Wind Turbine Blade Powder as a Reactive Component in Glass Fiber Reinforced Epoxy Composites

ABSTRACT Wind turbine blades are mainly composed of fiber‐reinforced epoxy thermosets possessing highly crosslinked networks and extremely low chemical reactivity, which severely limits their recyclability. Conventional physical recycling converts blade waste into inert fillers, resulting in significant deterioration of composite performance. Here, solid‐state shear milling (S3M) is employed to induce mechanochemical grafting of epoxy‐functional molecules onto recycled blade powder, transforming it into a reactive component for thermosetting composites. Mechanochemical co‐milling with ethylene glycol diglycidyl ether (EGDE) markedly enhances powder reactivity and interfacial compatibility during curing. Incorporation of 10 wt.% modified blade powder into glass fiber‐reinforced polymer (GFRP) composites yields a tensile strength of 194.33 MPa, approaching that of pristine GFRP without recycled content. After surface modification with EGDE, the tensile modulus increases from 10.77 to 12.21 GPa. After surface modification with alkyl epoxy glycidyl ether (AEG) and EGDE, the ILSS increases significantly to 26.5 MPa and 26.7 MPa from 20.48 MPa, respectively. This work demonstrates a scalable mechanochemical strategy for converting thermoset composite waste into reactive feedstock, enabling high‐value reutilization of decommissioned wind turbine blades and providing a practical pathway toward sustainable recycling of crosslinked polymer composites.