Acrylonitrile copolymerization. VII Solvents effects in styrene copolymerization

The styrene‐acrylonitrile radical copolymerization kinetics have been studied for polymerizations carried out in two different solvents, toluene and dimethylformamide (DMF), in the whole range of monomer mixture compositions and at various dilutions. The copolymer prepared in toluene solutions are poorer in acrylonitrile than those prepared in bulk. The reverse situation is observed in DMF solution, where the polymerization rate is the highest. In the latter case, also for acrylonitrile rich mixtures, the relative polymerization rate of styrene tends to increase with conversion; this effect is attributed to preferential solvation of styrene. Possible explanation of these facts are briefly discussed.