Solvent-base mismatch enables the deconstruction of epoxy polymers and bisphenol A recovery

Fiber-reinforced epoxy composites are key materials for the construction of wind turbine blades and airplanes due to their remarkable mechanical strength properties. On the flipside, their physical and chemical inertness results in a lack of viable recycling technologies. Recently, tailored resins have been introduced, which allow controlled fragmentation of the polymer matrix and thus the recovery of embedded fibres. However, for the separated thermoset epoxy fragments, there is no recycling solution available, resulting in the loss of complex molecular structures during their disposal. Here, we report a chemical process for recovering bisphenol A (BPA) from epoxy resins using a mismatched base-solvent system at an elevated temperature. We demonstrate a combinatory disassembly process/chemical deconstruction strategy on a commercial tailored composite sample, isolating both fibres and the polymer building block. The recovered BPA could potentially be reused in established polymer production chains, thus closing the recycling loop and reducing the need for virgin resources. The use of an alkaline base mismatched with an apolar aromatic solvent provides a new route to disassemble thermoset epoxy resins resulting in the recovery of the polymer building block bisphenol A.