text: In 1935, H. Staudinger and co-workers found that the reaction of butadiene and SO at room temperature gives a second product in addition to 3-sulfolene. This second product is an amorphous solid polymer. By free-radical polymerization of 3-sulfolene in peroxide-containing diethyl ether, up to 50% insoluble high-molecular-weight poly-sulfolene was obtained. The polymer resists degradation by sulfuric and nitric acids.
  In subsequent investigations, polymerization of 3-sulfolene was initiated above 100 °C with the radical initiator azobis(isobutyronitrile) (AIBN). 3-sulfolene does not copolymerize with vinyl compounds, however. On the other hand, 2-sulfolene does not homopolymerize, but forms copolymers with vinyl compounds, e.g. acrylonitrile and vinyl acetate.