Simultaneous bisphenol A and glass fiber recovery from glass fiber-reinforced epoxy resins via NaOH-mediated alcoholysis

The limited recyclability of thermoset epoxy resins in fiber-reinforced composites presents a growing environmental challenge, particularly for the recovery of bisphenol A (BPA) from bisphenol A diglycidyl ether (BADGE)-based systems. Herein, we report an efficient depolymerization strategy based on a NaOH-mediated alcoholysis process. This approach represents a conceptual departure from current epoxy deconstruction strategies, which typically rely on either transition-metal catalysis or harsh acidic/alkaline conditions. Using an inexpensive and readily available base, BPA is recovered in yields of up to 90% under relatively mild conditions and short reaction times. Mechanistic analysis combining experiments and molecular dynamics reveals that polymer structure, particularly the type of amine curing agent, governs accessibility of catalytically active species and overall reactivity, with more flexible networks enabling enhanced accessibility to the polymer chains. The process is successfully extended to glass fiber-reinforced composites and real end-of-life wind turbine blades, enabling simultaneous recovery of both BPA and glass fibers, which retain mechanical properties comparable to virgin materials. Importantly, beyond monomer recovery, this work establishes a direct link between polymer network structure and depolymerization efficiency via combined experimental and molecular simulation insights, providing a previously underexplored framework for understanding thermoset deconstruction. A life cycle assessment (LCA) further demonstrates the potential of this approach as a base-mediated route to thermoset deconstruction with reduced environmental impact in comparison to current composite waste management practices, highlighting its potential for scalable implementation.