Synthesis of polyacrylonitrile via reverse atom transfer radical polymerization (ATRP) initiated by diethyl 2,3-dicyano-2,3-diphenylsuccinate, FeCl3, and triphenylphosphine

The reverse atom transfer radical polymerization (RATRP) technique using FeCl3/triphenylphosphine (PPh3) complex as a catalyst was applied to the living radical polymerization of acrylonitrile (AN). A hexa-substituted ethane thermal iniferter, diethyl 2,3-dicyano-2,3-diphenylsuccinate (DCDPS), was first used as the initiator in this iron-based RATRP initiation system. A FeCl3 to PPh3 ratio of 1:3 not only gives the best control of molecular weight and its distribution but also provides a rather rapid reaction rate. The rate of polymerization increases with increasing the polymerization temperature and the apparent activation energy was calculated to be 54.9 kJ mol(-1). Because the polymers obtained were end-functionalized by chlorine atoms, they were used as macro-initiators to proceed the chain extension polymerization in the presence of an FeCl2/PPh3 catalyst system via a conventional ATRP process. (C) 2005 Society of Chemical Industry.