Synthesis of well-defined polyacrylonitrile by atom transfer radical polymerization

Well-defined polyacrylonitrile (PAN) is synthesized using atom transfer radical polymerization (ATRP). ATRP with 2-bromopropionitrile is used as the initiator and CuBr/2,2′-bipyridine as the catalyst. Ethylene carbonate is used as the solvent to provide solubility for the catalyst and the resulting polymer. First-order kinetics for all polymerization show curvature after initially being linear due to interaction between the nitrile groups on the PAN and the copper ions. Inspite of the these interactions, however, the preparation of PAN is successfully controlled by ATRP, leading to polymers with predetermined molecular weights and low polydispersities.