The invention relates to a preparation method of branched
polystyrene-
maleic anhydride, comprising the steps of: (1) under normal pressure, dissolving p-vinylbenzyl mercaptan,
styrene,
maleic anhydride, and an initiator for free
radical polymerization in a
polymerization solvent; (2) under stirring, heating the solution obtained in step (1) to a temperature of 30-40DEG C and introducing
nitrogen to the solution, sealing the reaction container, keeping stirring, raising the temperature of the solution to 65-80DEG C and preserving the heat for a reaction of 10-24h; (3) after the reaction, conducting pumping
filtration to the solution obtained in step (2), leaching the
solid from
filtration with a hot precipitating agent, then dissolving the
solid in an
organic solvent, filtering out insoluble impurities therein, conducting
precipitation and pumping
filtration to the obtained solution in a precipitating agent, subjecting the
solid obtained from filtration to
dissolution,
precipitation and pumping filtration, and carrying out
vacuum drying to the generated solid. According to the invention, the
polymerization conditions are mild, the polymers have controllable structural performance, and the
polymerization product has excellent performance, simple and convenient preparation operations, as well as good application.