Iron-mediated atom transfer radical polymerizations with activators generated by electron transfer of methyl methacrylate in N, N-dimethylformamide solution in the presence and absence of a limited amount of air, using FeCl(3-)6H(2)O as the catalyst, ethyl 2-bromoisobutyrate (EBiB) as the initiator, vitamin C as the reducing agent, and a commercially available organic acid, sulfosalicylic acid (SSA), as the ligand were investigated. Addition of SSA as the ligand could enhance the polymerization rate, and produce poly(methyl methacrylate) with controllable molecular weights and narrow molecular weight distributions (M-w/M-n = 1.30-1.50). The effect of [FeCl(3-)6H(2)O](0)/[ SSA](0) on the polymerization was studied by cyclic voltammetry characterization. Chain extension was performed to confirm the "living''/controlled nature of the polymerization system. (C) 2012 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 664-671