Iron-mediated atom transfer radical polymerization of styrene with tris(3,6-dioxaheptyl) amine as a ligand

The atom transfer radical bulk polymerization of styrene with FeX2 (X = Br or Cl)/tris(3,6-dioxaheptyl) amine as the catalyst system was successfully implemented at 110 degrees C. The number-average molecular weight of the polymers with a narrow molecular weight distribution (weight-average molecular weight/number-average molecular weight = 1.2-1.5) increased linearly with the monomer conversion and matched the predicted molecular weight. The polymerization rate, initiation efficiency, and molecular weight distribution were influenced by the selection of the initiator and iron halide. The high functionality of the halide end group in the obtained polymers was confirmed by both H-1 NMR and a chain-extension reaction. Because of its water solubility, the iron complexes could be removed easily from the reaction mixture through the washing of the polymerization mixture with water. (c) 2005 Wiley Periodicals, Inc.