Styrene-maleic anhydride grafted polyethylene glycol and preparation method thereof

The invention relates to styrene-maleic anhydride grafted polyethylene glycol and preparation method thereof. The preparation method comprises the following steps: with styrene and maleic anhydride as comonomers, synthesizing a styrene-maleic anhydride copolymer under the action of benzoyl peroxide; with the styrene-maleic anhydride copolymer as a substrate for chloromethylation reaction, introducing a reactive group onto a phenyl ring in a carbon chain of the polymer through the chloromethylation reaction; synthesizing the styrene-maleic anhydride grafted polyethylene glycol though nucleophilic substitution reaction of polyethylene glycol and chloromethyl. The preparation method is mild in reaction conditions, short in reaction time and high in yield.