Effects of solvent as an electron-pair acceptor on propagation reactions during radical polymerization and copolymerization of polar vinyl monomers

We carried out radical homopolymerization and copolymerization in various k inds of solvents at 60 degrees C by using diisopropyl fumarate (DiPF) and m ethyl methacrylate (MMA) as electron-accepting polar monomers and styrene ( St) and vinyl benzoate (VB) as electron-donating monomers. The highest poly merization rate was observed in the polar and electron-pair accepting solve nts, such as 2,2,2-trifluoroethanol for the homopolymerization and copolyme rization of these monomers. It has been revealed that the polymerization ra te is correlated to the electron-pair-accepting property of the solvent use d, rather than the polarity in the linear free energy relationship. We have demonstrated the validity of the acceptor number as the index for interpre ting the interaction of the solvent with the monomer and the propagating ch ain end. The monomer reactivity ratios were determined for the St-DiPF, VB- DiPF, and St-MMA copolymerizations. (C) 1999 John Wiley & Sons, Inc.