Terpolymerization of sulfur dioxide and methyl acrylate with electron donor monomers

Abstract

The radical terpolymerization of sulfur dioxide and methyl acrylate with 1,3-butadiene, 2-methylpropene, propene, I -hexene, 1 -octene and vinyl chloride was studied by comparing the composition of terpolymers obtained under different reaction conditions and by analysis of I3C NMR spectra of selected terpolymers and copolymers. In the majority of systems studied, products are formed in which the ratio of SO, monomeric units to vinyl monomeric units is near to unity. The content of methyl acrylate monomeric units can change over a very wide range and depends mainly on the electron-donor properties of the vinyl monomer used, feed composition and conversion. An increase of the methyl acrylate content is also observed in many systems with a rise of the reaction'temperature. The results obtained are interpreted in terms of a mechanisms involving the addition of individual monomers and reversibility of steps in which carbon-sulfur bonds are formed.There is only a limited number of literature reports on the reactivity of monomers in systems containing SO2 and a competitive electron-acceptor monomer9~ I I ) . In a previous paperto), we reported the results of studies on the relative reactivity of SO, and different electron-acceptor monomers in the terpolymerization with 1 -hexene or 1,3-butadiene at -78 "C. Maleic anhydride, acrylonitrile, acrylic acid, methyl acrylate and methyl methacrylate were used as acceptor monomers. In systems with maleic anhydride, alternating copropagation of the electron-donor monomer proceeds with both electron-acceptor monomers, of which SO, is more reactive. In systems with acrylic monomers, the alternating copropagation of both acceptors with