Copolymerization of Sulfur Dioxide with Unsaturated Compounds

CONDITIONS OF COPOLYMERIZATION OF SULFUR DIOXIDE WITH UNSATURATED COMPOUNDS 

Sulfur dioxide does not homopolymerize, but on reaction with olefins it yields copolymers.Terminal olefins react more readily than those with an internal double bond. The presence of various substituents affects the rate of polymerization. Conjugated dienes copolymerize with sulfur dioxide to give linear polymers containing residual double bonds. 

The copolymerization reaction is free radical in nature and is catalyzed by such initiators as peroxides [10], oxygen, azo compounds [11,11a], and light [9a, 12]. Styrene dissolved in liquid sulfur dioxide and catalyzed by stannic chloride (cationic catalyst) gives only polystyrene whereas the use of azo-bisisobutyronitrile gives poly(styrene sulfone). 

Sulfur dioxide is a gas at ordinary temperatures and has the following physical properties. 

Reactions with sulfur dioxide are carried out in pressure vessels constructed of glass or stainless steel. Caution should be used and all reactions should be done under a hood and behind a barrier for protection. 

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