Study On Aqueous Dispersion Polymerization Of Starch Graft Cationic Polyacrylamide

On the basis of the relevant literature,the synthesis of aqueous dispersion polymerization of starch graft cationic polyacrylamide(S-g-CPAM) was studied in this paper. At the same time, the flocculation performances of the prepared dispersions were discussed.1. Acrylamide(AM) was selected as main raw material, dimethylaminoethyl methacrylate methyl chloride(DMC) as the cationic co-monomer, poly(dimethylami- noethyl methacrylate methyl chloride)(PDMC) as stabilizer and redox system of ammonium persulfate/sodium bisulfite as initiator, the S-g-CPAM copolymer was synthesized by aqueous dispersion polymerization in ammonium sulfate solution.2. The effects of varying factors, i.e. the weight ratio of starch with monomers, the DMC content, the dosage of initiator, the concentration and molecular weight of the dispersant, the concentration of AS, the reaction temperature and time on the polymerization process, the product characters(grafting and grafting efficiency) and the stability of the system were investigated. Using the single-factor experiments, the optimum conditions of synthesis were determined as follows: the weight ratio of starch with monomers was 1:3, the content of cationic monomer was 10.0%, the dosage of initiator was 2.45×10^-3 mol·L^-1, the molecular weight of stabilizer was 43.4×104, the concentration of stabilizer was 2.0%, the concentration of ammonium sulfate was 35%-40%, the reaction temperature 60℃and reaction time 3h.3. The aqueous dispersion copolymers were characterized by Fourier Transform Infra-Red(FTIR), it revealed that the main chain units of starch,AM and DMC were showed in the FTIR figure, the graft copolymerization was proved.4. The prepared copolymer S-g-CPAM aqueous dispersions were used as flocculant to treat the kaolin suspended solution simulated as waste water. The influences of the cationic degree, the grafting and the dosage on flocculation efficiency were investigated. It was found that the copolymer with 10.0% cationic degree, the higher grafting performed a better flocculant effect. The optical dosage was 2.0mg·L^-1.