Kinetics and mechanism of free radical crafting of methyl acrylate onto sago starch

The graft, copolymerization was carried out by methyl acrylate with sage st arch in which eerie ammonium nitrate was used as an initiator. It has been found that the rates of graft polymerization and grafting efficiency were d ependent upon the concentration of eerie ammonium nitrate (CAN), methyl acr ylate (MA), sage starch (AGU, anhydro glucose unit), mineral acid (H2SO4), and as well as reaction temperature and period. A rate equation of polymeri zation was established from the proposed reaction mechanism, and the rate o f polymerization (R-p) was the first-order dependence of the MA monomer con centration and square root of the CAN concentration. A new kinetic model of the grafting reaction has been proposed, and a normal kinetics of methyl a crylate polymerization was observed. An equation of a predicted model relat ing the graft fraction of poly(methyl acrylate) with the sage starch has be en derived, and validity of the predicted model was verified by the experim ental results. (C) 2000 John Wiley & Sons, Inc.