▎ 摘　　要

NOVELTY - A preparation method of multifunctional flame retardant material comprises (S1) synthesizing graphene oxide nanosheets using Hummers method, (S2) ultrasonically mixing a graphene aqueous solution with a cellulose nanofiber aqueous solution, dripping heated melamine borate aqueous solution into the mixed solution under stirring conditions, and continuing to mix in a high-temperature water bath to form a gel and (S3) transferring the gel solution obtained in step (S2) to a mold, and drying in a blast oven to obtain a composite film; or constructing a coating by dip coating and drying to obtain the flame retardant coating. USE - The method is used for preparing multifunctional flame retardant material, which is applied on the polyurethane foam material by dip coating as a flame retardant coating for improving the flame retardant performance of the material. The multifunctional flame retardant material is used for constructing fire early warning sensor system (all claimed), such as infrared sensors and smoke sensors. The multifunctional flame retardant material is used as a flame retardant coating on polymer foam, and in fire safety and protection. ADVANTAGE - The multifunctional flame retardant material has high-efficiency flame retardance, rapid fire early warning function and improved solvent resistance.