▎ 摘　　要

A novel functionalized graphene oxide (F-GO) decorated with a double-phosphaphenanthrene structure was fabricated using a covalent modification method. The F-GO with Bi-DOPO groups then was introduced into the epoxy matrix as a highly effective flame retardant. The Flame retardant epoxy resins (FREP) containing F-GO exhibited superior fire-resistant performance with extremely low loading. When the content of F-GO was 1 wt%, the limiting oxygen index value of the FREP was increased from 19.9% to 30.8%, and the total heat release and the peak heat release rate was decreased by 44.0% and 55.5%, respectively. Meanwhile, the tensile and impact tests results indicated that the mechanical properties of the epoxy resins were improved with the addition of F-GO. Furthermore, the thermogravimetric analysis showed that F-GO greatly increased the char-yield of the cured FREP. Based on the char analyses of SEM images, F-GO was conducive to form a more protective char barrier for FREP during combustion. F-GO developed a synergistic flame-retardant effect of the Bi-DOPO derivative and graphene layer structures on epoxy resins.