Graft Copolymerization Of Starch And Acrylamide By RATRP In Inverse Emulsion

During starch graft acrylamide polymerization in inverse emulsion, Fe(EDTA)2-was added to form complex initiation system with ammonium persulfate (APS) and which was oxidized to Fe(EDTA)-. The controlling effect of Fe(EDTA)-on the inverse emulsion starch graft acrylamide polymerization was explored. It can be conclude that Fe(EDTA)2-has a dual role of reducing agent of oxidation-reduction initiation system and potential catalyst of reverse atom transfer radical polymerization (RATRP). By adding Fe(EDTA)2-complex, the defects, such as undesirable rise of temperature and thus uncontrollable of the reaction and cross-linking of products, have been overcome and controllable copolymerization of starch and acrylamide in inverse emulsion has been achieved.In the study of acrylamide polymerization reaction in inverse emulsion, when the concentration of Fe(EDTA)2-is2.8×10-4mol/L, n[(NH4)2S2O8]:n(FeSO4):n(Na2EDTA)1:1:1.10, reaction time is6h, the content of emulsifier is3%, reaction temperature is40℃, the final conversation of monomer is93.16%. Polyacrylamide emulsion has good stability, the molecular weight increased linearly with the monomer conversion, with a linear correlation coefficient of0.995, and the kinetic curve showed a good linear relationship, with a linear correlation coefficient of0.997, which indicated that the polymerization has controllability in the presence of Fe(EDTA)-. Thus it can be conclude that Fe(EDTA)2-has a dual role of reducing agent of oxidation-reduction initiation system and potential catalyst of reverse atom transfer radical polymerization.In the study of graft copolymerization of starch and acrylamide in inverse emulsion, when the reaction temperature is45℃, concentration of Fe(EDTA)2-is3.4×10-4mol/L, n(NH4)2S2O8]:n[FeSO4]:n[Na2EDTA]=1:1:1.15, concentration of initiator is3.4×10-4mol/L, the mass ratio of starch and acrylamide is1:1.6, the content of emulsifier is5%, the conversion of monomer is upto97.77%and the grafting ratio is135.4%, the specific viscidity of the product is390.8ml/g, and the copolymer emulsion has fairly good stability.