Study on graft copolymerization of acrylamide onto mechanical activated maize starch

Maize starch was mechanically activated by a stirring-type ball mill. Using ammonium persulfate-sodium bisulfate as initiator, acrylamide as monomer, graft copolymer was synthesized from maize starch with different activation time. The effects of mechanical activation time, reaction time, reaction temperature, initiator amount and monomer amount on graft copolymerization of maize starch were investigated respectively by using grafting rate (G) and grafting efficiency (GE) of graft copolymer as evaluating parameter. The results indicated that mechanical activation considerably enhanced the graft copolymerization of maize starch, the G and GE increased with increasing activation time. Moreover, it was also found that other affecting factors had a certain influence upon graft copolymerization and were closely related to the activation time of maize starch, and the effects of reaction temperature, initiator and monomer concentrations on graft copolymerization were reduced with increasing activation time.