Chemical Recycling of Waste Wind-Turbine Blades Through Polymer Deconstruction and Upcycling

The rapid expansion of the wind energy industry is generating an increasing volume of waste wind-turbine blades (WWTB), creating an urgent need for efficient and sustainable recycling technologies. Composed primarily of cross-linked epoxy resins reinforced with glass or carbon fibers, WWTB are inherently difficult to recycle, resulting in substantial resource loss and environmental burdens. Chemical recycling has emerged as one of the most promising approaches because it enables the selective cleavage of C─O, C─C, and C─N bonds within thermoset networks, allowing controlled depolymerization while preserving the value of reinforcing fibers. This review presents a comprehensive, mechanism-oriented perspective by establishing a unified framework that integrates substrate structure, bond-cleavage mechanisms, reaction-pathway regulation, catalyst design, product separation, and product valorization. It reveals how the intrinsic chemical structure of thermoset composites governs bond activation, directs reaction pathways, and ultimately determines recycling efficiency and product selectivity. Guided by this framework, we examine recent advances in catalytic degradation, reactor design, downstream separation, and the high-value utilization of recovered fibers and depolymerization products. Finally, we discuss the key scientific challenges and future directions for developing efficient, selective, and sustainable recycling technologies for WWTB and other thermoset composites.