▎ 摘　　要

NOVELTY - Graphene oxide-based flame retardant comprises graphene oxide and phosphazene. The mass ratio of graphene oxide to phosphorus in phosphazene is 1:(0.25-5). USE - The flame retardant and the copolyester are useful in textile (claimed). ADVANTAGE - The flame retardant: uses phosphazene to graft and modify graphene oxide; can improve the phenomenon of graphene oxide agglomeration at high temperature, and achieves synergistic flame retardancy effect by grafting flame retardant elements on the surface of graphene oxide. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: preparing graphene oxide-based flame retardant comprising (a) dispersing graphene oxide to obtain a uniform suspension and (b) adding phosphazene or phosphazene solution into the suspension to react to obtain graphene oxide-based phosphorus nitrogen composite flame retardant; preparing graphene oxide-based flame-retardant copolyester comprising soaking polyester fibers in the dispersion liquid of graphene oxide nitrogen-phosphorus composite flame retardant or graphene oxide nitrogen-phosphorus-silicon composite flame retardant for reaction, washing and drying to obtain the graphene oxide-based flame retardant copolyester; and a graphene oxide-based flame-retardant copolyester prepared by the above method.