Study On Inverse Emulsion Graft Polymerization Of Acrylamide Onto Cassava Starch

The water-oil inverse emulsion was prepared in present of cassava starch and acrylamide with the compounds of Span80 and Tween80 as emulsifier. The effect factors on the types and stability of the inverse emulsion were discussed, such as the HLB value of mixed emulsifier, the oil/water ratio, the content of the mixed emulsifier et al. And the four effect factors, such as temperature, time, concentration of initiator and mass ratio of acrylamide to starch, on the polymerization ratio, graft ratio and graft efficiency were discussed. The structure of product was characterized by FTIR, SEM, X-ray Diffraction and TG-DSC. And the applied property of the product was studied. The results indicated:With the cassava as raw material, liquid paraffin as dispersion medium,the compounds of Span80 and Tween80 as emulsifier, the optimum conditions for forming stable water-oil inverse emulsion were: the HLB value of mixed emulsifier at 6.49, the mass ratio of oil to water on 1:1, and the content of the mixed emulsifier at 3%.The optimum conditions of the graft copolymerization of acrylamide onto cassava starch were determined by orthogonal experiments as temperature at 50℃, time in 3 hours, the concentration of initiator in 0.0175 mol·L-1, and mass ratio of acrylamide to starch in 3:2. And the graft efficiency was 95.10 %.The analysis results of FTIR , SEM, X-ray Diffraction and TG-DSC proved that,the existence of graft copolymerization between cassava starch and acrylamide was occured;the structures of cassava were destroyed during the copolymerizing; the structures of the copolymer were largely amorphous; within the range of 700℃,the thermal degradation process of the St-g-PAM was divided into three-steps, which was more complex than that of cassava.The application result indicated that the product had good flocculation effects to the effluent, the kleit, and the yellow clay.