Effect of Inhibitors on Atom Transfer Radical Polymerization of MMA

Effect of a series of inhibitors as additives on atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) with FeCl2/PPh3 as catalyst system was studied, including 2,4,6‐trinitrophenol (TNP), 4‐methoxyphenol (4‐MP), hydroquinone (HQ) and nitrobenzene (NB). It was found that TNP was the only efficient additive for ATRP among these inhibitors. In the presence of small amounts of TNP, the polymerization proceeded rapidly after induction period to yield the polymers with controlled molecular weights and narrow molecular weight distributions (MWD). The initiating efficiency of the modified catalyst system with TNP was increased. The mechanism was proposed and confirmed by the end group analysis of the polymer.