Study on the synthesis of starch graft acrylamide copolymer and its flocculent effect

The starch graft copolymers was synthesized with taking cornstarch and acrylamide as raw materials by using potassium persulfate as initiator.The structure of the copolymer was confirmed by FTIR and the molecular weight was tested by viscosity law.The factors of polymerization to graft copolymerization reaction has been discussed and the flocculating property of the copolymer product was determined using aqueous suspension of kaolin.The optimum conditions were that concentration of initiator was 0.07 g/100 mL,m(cornstarch) ∶m(acrylamide) was 1 ∶2.2,reaction temperature was 65 ℃,reaction time was 3 h.The flocculation experiment reveals that comparing to the PAM which the molecular weight was four point three million,the product has the same flocculent effect to aqueous suspension of kaolin.When the graft copolymer flocculant is 6 mg/L,the removal rate of turbidity can reach 81.77%.The molecular weight will reach 750 thousand at the optimum conditions.