Reverse Atom Transfer Radical Polymerization of Acrylonitrile Catalyzed by FeCl3/Lactic Acid

Reverse atom transfer radical polymerization (RATRP) of acrylonitrile (AN) was carried out using azobisisobutyronitrile (AIBN) as initiator, ferric trichloride anhydrous (FeCl3)/lactic acid (LA) as catalyst system; a ratio of FeCl3/LA was 1:2 gave the best control. RATRP of AN with N,N-dimethylformamide (DMF) as solvent gave the moderate polymerization rate and the narrowest polydispersity index (PDI). When FeCl3 was replaced by CuBr2, RATRP of AN showed a longer induction period. When Cu was added to the CuBr2-based catalyst system, the induction period was reduced. 1H-NMR spectra of PAN verified the possibility of controlled/living polymerization for future chain extension.