Copolymerization of Vinyl Chloride and Sulfur Dioxide. II. Copolymerization Rates and Copolymer Compositions

The rate of copolymerization of vinyl chloride (VC) with sulfur dioxide and the composition of the poly (vinyl chloride sulfone) formed have been measured for comonomer liquid mixtures with XVC = 0.1 to 1.0 and over the temperature range -95 to +46°C. Polymerization was initiated by γ-irradiation (-95 to +46°C) and with the t-butyl hydroperoxide/SO2/methanol redox system (-95 to -18°C). The copolymerization rates and copolymer compositions indicated two distinct temperature regions, with a change in mechanism around 0°C. For radiation initiation below 0°C, the rate versus comonomer composition relationship showed a maximum at an xVC value which increased with increasing temperature. Above 0°C, the rate decreased with increasing temperature and was greatly retarded by SO2. No high molecular weight copolymer or VC homopolymer was formed on irradiation of comonomer mixtures above ∼55°C.