Toward sustainable thermosets: Advances in toughening and degradation strategies for epoxy resins

Epoxy resins (EPs) are widely used thermosetting plastics with excellent mechanical and thermal properties. Due to their highly crosslinked network structure, EPs are relatively brittle and non-degradable. Enhancing toughness and degradability are important research topics of sustainable applications for EPs. This review presents a comprehensive analysis of toughening strategies and degradation techniques for EPs, emphasizing molecular-level design principles that balance mechanical performance with environmental sustainability. On one hand, we systematically review recent advances in toughening strategies that overcome the traditional strength-toughness trade-off, enabling the simultaneous enhancement of both properties. On the other hand, we critically analyze green degradation techniques, focusing on their mechanisms, advantages, and limitations. Moreover, we highlight pioneering studies that synergistically improve toughness and degradability through innovative molecular design. Furthermore, we discuss key considerations for developing high-performance (tough yet strong) and degradable EPs, identify remaining challenges, and outline future research directions in this evolving field.