Graft Co-polymerization of Acrylamide onto Starch in Inverse Emulsion

Graft co-polymerization of acrylamide onto cassava starch in a five-component inverse emulsion system, starch/monomer/emulsifier/water/oil, was conducted with (NH4)2S2O8 as initiator. The effects of reaction temperature, ratio of starch to acrylamide monomer, concentrations of initiator and emulsifier, and the ratio of oil to water on the conversion of acrylamide, graft percent and graft efficiency were investigated. Meanwhile, the graft co-polymerization mechanism in inverse emulsion was described primarily. The results show that the influences of reaction temperature, ratio of starch to acrylamide monomer and initiator concentration on graft co-polymerization are predominant among the five factors mentioned above. The emulsifier content and the ratio of oil to water are two main factors for forming inverse emulsion and maintaining its stability. It is believed that in the five-component inverse emulsion system, graft co-polymerization of acrylamide monomer onto cassava starch occurs at the surface of the starch granules.