Free radical grafting kinetics of acrylamide onto a blend of starch/chitosan/alginate

Grafting of monomer onto polymer backbone is one of the effective and accessible methods for the chemical modification of polysaccharides. Grafting of acrylamide (AAm) onto polysaccharides blend (PsB) composed of starch, chitosan and alginate has been carried out using potassium persulfate (KPS) as an initiator. The kinetics of the grafting polymerization also has been studied. The grafting parameters have been evaluated by changing the initial concentrations of AAm from 8 to 16 g, PsB from 6 to 14 g and KPS from 0.2 to 1 g. Evidence of grafting has been obtained from FTIR, XRD and TGA. The kinetics of the grafting polymerization also has been studied. The grafting rate equation of the produced hydrogel (PsB-g-AAm) hydrogel has been expressed by: Rg = k[AAm] [PsB]0.5 [KPS]0.5. The grafting rate is a first order dependence to [AAm] initial concentration and square root to [PsB] and [KPS] initial concentrations in the used concentrations range.