Fire-retardant recyclable epoxy systems based on covalent adaptable networks

Abstract Epoxy resins (EPs) are widely used in structural and functional applications due to their excellent mechanical properties, chemical resistance, and dimensional stability. However, their inherent flammability and non-recyclability pose significant fire safety and environmental challenges. The emergence of dynamic covalent chemistry and advanced flame-retardant strategies has enabled the design of EP systems with both recyclability and intrinsic flame retardancy. Nevertheless, the introduction of reversible dynamic covalent bonds to facilitate network adaptability often compromises structural integrity, resulting in increased susceptibility to creep and deteriorated in-service performance (e.g., mechanical properties, thermal stability, and durability). This review outlines the state-of-the-art research on flame-retardant, recyclable EPs in recent years and highlights feasible and potential strategies to improve the creep resistance and in-service performance of flame-retardant, recyclable EPs. Finally, potential future development directions for the development of flame-retardant, recyclable and high-stability EPs are proposed.