Polymerization of acrylonitrile initiated by samarium diiodide in the presence of hexamethylphosphoramide.

The paper presents the polymerization of acrylonitrile (AN) initiated by samarium diiodide (SmI2) combining with hexamethylphosphoramide (HMPA) for the first time. The effects of various parameters, such as reaction temperature, AN/Sm and HMPA/Sm molar ratios, reaction time on the polymer yield and its molecular weight were discussed. On the basis of both IR and NMR analysis of resulted polymers, a single-electron-transfer initiation mechanism of AN as radical anion was proposed for this polymerization, which was further sustained by the copolymerization of AN with <f>&epsiv;</f>-caprolactone and 2,2-dimethyltrimethylene carbonate, respectively. [Copyright &y& Elsevier]