Reaction kinetics of graft copolymerization and thermochemical studies of the degradation of poly(vinyl alcohol) graft copolymer

摘要

Poly(vinyl alcohol) (PVA) is a water-soluble and biomedical polymer. 2-Acrylamido-2-yl-l-propanesulfonic acid was grafted onto PVA using ammonium persulfate as radical initiator. influences of synthesis conditions such as temperature, concentrations of initiator, PVA andwnomer were investigated. Both the initial rate of grafting and the final percentage of grafting were icreased by an increase in reaction temperature. The reaction kinetics were studied to determine the Ic constants of the first-order reactions. An activation energy of 16.3kJ mol’ was found for the g reaction. The graft copolymers were characterized by IR and intrinsic viscosity measure-- . A proposed mechanism of the grafting reaction is discussed. Kinetics of the thermal ~adation were studied using a thermogravimetric method and the order of thermal stabilities are-en. The apparent activation thermodynamic parameters, Ea~ AH*, AS* and AG* were determined correlated to the thermal stabilities of the homo- and grafted polymers.