Anionic polymerization of methyl methacrylate initiated with molybdenum and tungsten chloride/organolithium/triisobutylaluminum systems

Abstract

AbstractMolybdenum chloride (MoCl5 or 1a) and tungsten chloride (WCl6 or 1b)/phenyllithium (PhLi)/triisobutylaluminum (iBu3Al) systems were found to be quite effective for controlling the anionic polymerization of methyl methacrylate (MMA), affording high molecular weight poly(methyl methacrylate)s (PMMAs; number‐average molecular weight > 100,000) with narrow molecular weight distributions (weight‐average molecular weight/number‐average molecular weight < 1.25) quantitatively at 0 °C for 1 h in toluene. Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) analyses of PMMAs obtained with the 1a and 1b/organolithium (RM; n‐butyllithium, PhLi)/iBu3Al systems revealed that the initiation of MMA with the systems occurred by a nucleophilic attack of H− to the monomer. In addition, the MALDI‐TOF MS analyses indicated that the presence of iBu3Al was responsible for the controlled polymerization by improving the uniformity of the polymerization with respect to initiation and termination and by preventing a backbiting reaction. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4302–4315, 2002