Microwave-assisted catalyzed solvolysis for rapid recycling of wind turbines composites

The recycling of end-of-life (EoL) wind turbine blades is an urgent, still unsolved challenge, due to the thermoset nature of the epoxy matrices used for their fabrication and to the low economic value of the recovered glass fibers. In this work, a microwave-assisted process is developed to intensify the chemical recycling of fiber-reinforced anhydride-cured epoxy composites, enabling rapid, energy-efficient, and economically viable solvolysis under mild reaction conditions. Unlike previously reported microwave-assisted oxidative processes, the selection of a catalyst-assisted solvolysis method in non-oxidative conditions ensures the selective cleavage of the polymeric network, preserving the properties of the fibers while recovering valuable and reusable organic fractions. Compared to conventional heating (200 °C, 2 – 4 h), microwave irradiation (0.6 kW) enabled complete fiber liberation within around 15 min, leading to a drastic reduction in energy demand (1.92 kWh vs. 0.13 kWh per batch reaction). The reclaimed fibers maintained good mechanical and adhesion properties, significantly outperforming the conventionally recycled counterpart. The recovered organic recyclates showed consistent chemical composition, demonstrating that different heating sources do not affect the reaction mechanism, and confirming their potential zero-waste reusability for the production of second-generation components. The successful validation of the process on real EoL wind turbine fragments demonstrates that microwave-assisted mild solvolysis represents a scalable and industrially relevant strategy for the circular recycling of wind turbine blade composites, combining high material recovery yields, reduced energy consumption, and preservation of fiber performance.