Alkali metal alkoxide derivatives of starch and dextrin as initiators of graft polymerization of methacrylonitrile

The anionic graft polymerizations of methacrylonitrile on starch in dimethylsulphoxide, initiated by the lithium and sodium alkoxide derivatives, were studied; the results were compared with those previously obtained with the corresponding potassium alkoxide. With lithium the results were not highly reproducible, but with sodium the results were reproducible as seen from the balance of monomer and starch at the end of the polymerization. The yields of pure graft polymer were in the order K > Na > Li; lower alkoxide concentrations were required for attaining full conversion and optimal yields in the case of the potassium alkoxide. The graft polymerization of MAN on the potassium alkoxide derivative of dextrin was studied; the effects of alkoxide and monomer concentrations as well as of temperature were examined. Comparison of the results with those obtained previously with starch indicate that the type of the carbohydrate backbone does not effect the graft polymerization to a significant extent.