Graft Polymerization of Isobornyl Acrylate and Isobornyl Methacrylate onto cis-Polybutadiene - A Kinetic Study

Abstract

The radical induced grafting of isobornyl acrylate (IBA) and isobornyl methacrylate (IBM) onto cis-polybutadiene (PBD) has been studied in toluene at 70ºC using benzoyl peroxide (BPO) as an initiator. The effect of monomer concentration on grafting yield shows that the grafting yield increases up to 0.60 monomer concentration and then remains almost constant. A logarithmic plot of rate of grafting against monomer concentration gives a linear relationship giving order with respect to IBA as 1.33 and IBM as 1.22. The formation of graft copolymers and the site of grafting were confirmed by IR spectra. The grafting of IBA on PBD occured on the double bond position and that of IBM on vinylic position. The grafting yield was increased with increasing initiator concentration up to 0.030 g. The variation of graft yield with reaction time shows that grafting yield increased initially with increase in the reaction time and then remained almost constant. Increasing temperature increases the graft yield up to certain temperature and then it decreases at higher temperature. This is due to the mutual termination of initiating free radicals. Thermogravemetric analysis has been studied for homo- and graft copolymers. Initial decomposition temperature (IDT) and decomposition temperature at 50 % weight loss have been determined. Intrinsic viscosity measurements on the graft copolymer has been determined.