Halogen-free flame-retardant toughening agent as well as preparation method and application thereof

The invention relates to the technical field of polymer flame retardance and toughening, and discloses a preparation method of a halogen-free flame-retardant toughening agent, which comprises the following steps: S1, dissolving polyglycol and triethylamine in an organic solvent to obtain a mixed solution I; S2, dissolving a phosphorus oxychloride compound in an organic solvent to obtain a mixed solution II; S3, dropwise adding the mixed solution II into the mixed solution I, and reacting at 0-25 DEG C for 0.5-1 hour to obtain a reaction solution I; S4, dissolving an imidazole compound in an organic solvent to obtain a mixed solution III; S5, mixing the mixed solution III with the reaction solution I, carrying out condensation reflux reaction at 50-80 DEG C for 12-24 hours, and cooling to room temperature to obtain a reaction solution II; S6, purifying the reaction solution II to obtain the halogen-free flame-retardant toughening agent. The halogen-free flame-retardant toughening agentdisclosed by the inventio