Controlled/“Living” Radical Polymerization of Styrene and Methyl Methacrylate Catalyzed by Iron Complexes

Controlled/“living” radical polymerization of styrene and methyl methacrylate has been achieved by atom transfer radical polymerization (ATRP) catalyzed by iron halide complexes under both homogeneous and heterogeneous conditions. A variety of coordinating ligands have been used including 4,4‘-bis(5-nonyl)-2,2‘-bipyridine, trialkylamines, triphenylphosphine, trialkylphosphines, and trialkylphosphites. The polymer number-average molecular weight (Mn) increases linearly with monomer conversion and matches the predicted molecular weight. The polymerization rate and molecular weight distribution (Mw/Mn = 1.1−1.5) are affected by the structure of the coordinating ligands and the monomers employed.