▎ 摘　　要

NOVELTY - Functionalized graphene of phosphorus-nitrogen type flame retardant is represented by (I). USE - Functionalized graphene of phosphorus-nitrogen type flame retardant. ADVANTAGE - The functionalized graphene of phosphorus-nitrogen type flame retardant has strong graphene oxide surface with polarity, greatly enhances interaction of PLA segment, and has improves dispersibility in the matrix. DETAILED DESCRIPTION - Functionalized graphene of phosphorus-nitrogen type flame retardant is represented by formula (I). m and n=integers of 1-300. An INDEPENDENT CLAIM is included for a method for preparing phosphorus-nitrogen flame retardant functionalized graphene of formula (I), which involves: (A) dispersing graphene oxide (GO) in deionized water and performing ultrasonic treatment to promote sufficient dispersion of graphene oxide in water; (B) pre-dissolving branched polyethyleneimine (BPEI) in deionized water to prepare an aqueous solution, adding the above aqueous solution to the material to carrying out a reaction to obtain a polyethyleneimine grafted graphene oxide; (C) using dichloromethane as a solvent, adding 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) to the reaction vessel; (D) adding acid binding agent and the polyethyleneimine grafted graphene oxide to the above reaction vessel, placing reaction vessel in an ultrasonic cleaner for ultrasonic treatment; (E) transferring reaction vessel to an ice-water mixing bath, contorlling temperature to 0 degrees C, and adding catalyst carbon tetrachloride in dropwise to the reaction vessel; (F) transferring reaction vessel to room temperature, filtering reaction for 48-60 hours, and washing with deionized water and acetone; and (G) drying product in vacuum to obtain final product.