Mechanism of surface control reaction and characterization of graft copolymers of acrylamide onto starch

The starch acrylamide graft copolymers (St-g-PAM) were synthesized by inverse emulsion polymerization with cassava starch and acrylamide as raw materials and ammonium persulfate as the initiator.The structures of St-g-PAM were characterized with Fourier transform infrared spectroscopy (FTIR), thermogravimetry (TG), differential scanning calorimetry (DSC), X-ray diffraction (XRD)and scanning electronic microscope (SEM).Meanwhile, the graft copolymerization mechanism in the inverse emulsion was discussed.The results showed that grafting copolymerization reaction occurred on the surface of the starch particle which was in agreement with the mechanism of surface control reaction.PAM grafted into the base of starch successfully, and the aggregation phase of raw starch was changed from semi-crystalline state to amorphous aggregation state due to the graft reaction of starch and acrylamide.However, the graft copolymerization of acrylamide onto starch did not alter the thermal stability of starch.