Enhanced B–N coordinated dynamic boronate chemistry for recyclable thermosets with elevated stability

The environmental impact of non-recyclable thermoset waste demands sustainable polymer solutions. Existing dynamic covalent boronic ester chemistries operate at relatively low temperatures (<150 °C), resulting in insufficient stability to meet thermoset performance requirements. Here, we overcome these limitations through a N-iminodiacetic acid (N-IDA) boronate system featuring a strengthened internal B–N coordination bond. This enhanced B–N bond (~1.65 Å) endows the dynamic covalent bonds with both exceptional thermal stability and controllable exchange above 150 °C. We leverage this chemistry to develop radical crosslinkers compatible with commercial monomers and thermoplastics. The resulting recyclable thermosets demonstrate exceptional thermal stability, chemical durability under harsh environments (85 °C/85% RH, 7 days), and excellent dimensional stability. This stability–exchange dichotomy is exemplified in heat-shrinkable crosslinked polyethylene (XLPE), where the enhanced B–N coordination maintains network integrity at service temperatures (<150 °C) while enabling thermal reprocessability above 150 °C. By extending the operational range of boronic ester-based dynamic chemistry to high temperature domains, this work provides a scalable pathway toward recyclable thermosets without stability compromises. Dynamic boronic ester chemistries enable recyclable thermosets, but their low exchange temperatures lead to poor stability and deformation during use. Here, the authors report recyclable thermosets using N-coordinated iminodiacetic acid boronates, achieving high thermal and environmental stability.