Recent progress and multifunctional applications of fire-retardant epoxy resins

To improve the fire retardancy of epoxy resins, researchers use modifiers such as graphene, phosphorus, boron compounds or similar compatible fillers. The quantity of modifiers introduced to the epoxy matrix is crucial because high loading leads to deleterious thermal and mechanical properties. Taking that into account, this review identified the best epoxy-based fire-retardant polymer pertaining to modifier proportion. In this perspective, we classified fire-retardant epoxy resins into three groups: (1) intrinsic, (2) blends, and (3) composites. A closer investigation of the performance-enhanced material compositions based on multifunctional fire-retardant epoxy resins was undertaken. The reviewed key ingredient materials included ionic liquids, phosphorus, boron/boron nitride, aluminum hydroxide, silicone, lignin, graphene, carbon fibers, carbon nanotubes, and clay. Moreover, this review elucidated the multifunctional applications of fire-retardant epoxy resins, factors affecting fire retardancy, and current characterization techniques, including Underwriters Laboratories 94 testing, cone calorimeter, limiting oxygen index, SEM, and GC-FTIR. Finally, we outlined further research possibilities for smart and effective fire-retardant materials.