Recyclable Bio‐Based Epoxy Vitrimer with High Strength‐Toughness via Restricted Phase Separation Strategy

ABSTRACT Epoxy thermosets are crucial for emerging energy applications owing to their outstanding mechanical properties and thermal stability. However, they are often constrained by a fundamental tradeoff among strength, toughness, and recyclability. Herein, a reactivity‐difference‐induced restricted phase separation strategy was proposed to overcome this challenge. Specifically, a bio‐based epoxy vitrimer (PTA‐A4B4) was designed and synthesized through a stepwise curing process. A rapid thiol‐epoxy click reaction first anchored flexible poly(thioctic acid) chains as soft segments, followed by carboxyl‐epoxy crosslinking that constructed a rigid matrix and together with thermodynamic immiscibility, drove the formation of a restricted phase separation architecture. The chemically confined soft domains served as efficient energy‐dissipation units, while the rigid, highly crosslinked furan epoxy network preserved high strength. The resultant vitrimer exhibited remarkable tensile strength (63.45 MPa) and toughness (3.75 MJ m −3 ). In addition, Artificial intelligence (AI)‐guided analysis identified the molecular balance between rigidity and flexibility as the decisive factor governing mechanical performance. More importantly, the vitrimer's inherent dual dynamic covalent networks enabled full reprocessability and closed‐loop recycling. The practical applicability was demonstrated through the fabrication of a fully recyclable glass fiber‐reinforced wind turbine blade. This work offers valuable insights for developing sustainable high‐performance materials.