Homogeneous and heterogeneous copolymerization of styrene and sulfur dioxide using the (CH₃)₃COOH/SO₂ redox system

Styrene was copolymerized with sulfur dioxide in the presence of tert‐butyl hydroperoxide under homogeneous and heterogeneous conditions. The rate of copolymer formation decreases in the order emulsion, suspension, organic–aqueous, and organic solution. The rate also depends on reaction time, temperature, solvent, and initiator concentration. Several physical methods used to characterize these copolymers, including IR, ¹³C‐NMR, elemental analysis, viscosity, softening point, and isothermal aging. Analysis of the composition of the resulting copolymers revealed that there are on the average about two molecules of styrene per SO₂ present on the copolymer chain. ¹³C‐NMR suggests that these copolymers are made up mostly of the MSM, SMM, and MMS triad monomer sequences whereas the SMS and MMM are present in small amounts. Characterization of polystyrene homopolymers shows that there is lack of stereoregularity in both homogeneous and heterogeneous polymerization systems.