Studies on Preparation of Hydrophobic Associating Cationic Starch Flocculant and its Flocculation Properties

[Objective] The study aimed to prepare a new hydrophobic associating cationic starch flocculant and research its flocculation properties.[Method] With the starch as raw material,the acrylamide and vinyl acetate as the monomer,the potassium sulfate as the initiator,a few ethanol as the mutual solvent and the formaldehyde and dimethylamine as the reagent for the cationization,the polymerization product was obtained through the grafted polymerization reaction and the a new hydrophobic associating cationic starch flocculant was prepared through the mannich reaction for the cationization.The grafted rate and amination rate were determined and finally the test of flocculation effect was conducted.[Result] The best synthetic process conditions for the new hydrophobic associating cationic starch flocculant was as follows: the mass ratio of starch-monomers being 1∶3,the initiator dosage of 1.25%(based on monomer),reaction temperature of 60 ℃,reaction time of 4 h,and the hydrophobic monomer ratio was 10%.The optimum reaction conditions for the Mannich reaction was as follows: the amide-formaldehyde-dimethylamine ratio of 1∶1∶1.5,reaction temperature of 60 ℃ and reaction time of 2 h.[Conclusion] The flocculant had good flocculation effect.