Recent progress on flame-retardant bio-based epoxy resins: Preparation methods and performance evaluation

With growing awareness of environmental protection and an increasing emphasis on sustainable development, bio-based epoxy resins have garnered significant attention due to their outstanding performance and eco-friendly characteristics. However, their inherent flammability restricts their broader application. Consequently, the development of efficient and environmentally benign flame-retardant technologies for bio-based epoxy resins is critical to advancing high-performance applications and fostering the development of sustainable materials. The four primary methods to enhance the flame retardancy were introduced, including molecular structure design, physical additives, reactive flame retardants, and flame-retardant coatings. This paper reviews the current flame-retardant technologies and research progress related to bio-based epoxy resins. Furthermore, the existing challenges and solution measures of bio-based epoxy resins in industrial application are analyzed, and cost-effectiveness, environmental impact, and life cycle assessment needs more attention. This study provides new insights into the design and application of flame-retardant bio-based epoxy resins.