Facile iron(iii)-mediated ATRP of MMA with phosphorus-containing ligands in the absence of any additional initiators

Abstract

A series of phosphorus-containing ligands was employed to establish a novel polymerization system for the iron(III)-mediated polymerization of methyl methacrylate (MMA) just using FeCl₃·6H₂O or FeBr₃ as the catalyst without any additional initiators and reducing agents. The polymerization results showed that this polymerization system involving MMA/FeX₃ (X = Cl, Br)/phosphorus-containing ligand was a typical “living”/controlled radical polymerization process: first-order polymerization kinetics with respect to monomer concentration and a linear increase of the molecular weight of the resultant PMMAs with conversion while keeping a narrow molecular weight distribution. Chain end analysis of the obtained PMMA based on ¹H NMR, ³¹P NMR were used to confirm the precise structure of the obtained polymers. The results showed that phosphorus-containing complexes acted as both ligand and thermal radical initiators in this process, which was consistent with a reverse atom transfer radical polymerization (reverse ATRP) mechanism.