Synthesis and Characterization of Graft Copolymers of Acrylic Acid onto Starch

A graft copolymer was synthesized in water-oil inverse emulsion by copolymerization of acrylic acid(AA) onto cassava starch,with N,N-methylene diacrylamide as cosslinking agent,potassium persulfate as an initiator.The orthogonal design of the important factors was utilized in this technique.The grafting copolymerization was analysed by FT-IR,XRD and TG.The optimum reaction conditions are 3.5 mass ratio of acrylic acid to starch,0.30% mass ratio of crosslinking agent to starch,3.0% mass ratio of initiator to starch,83.3% neutralization degree of acrylic acid,polymerization at 70 ℃ and 3 h.The water-absorbing rate of the prepared resin can reach 835 g/g at room temperature.It has been proved that PAA grafts into the base of starch successfully,and the aggregation phase of raw starch is changed from semi-crystalline state to amorphous aggregation state due to graft reaction of starch and acrylamide.