The Revival of Nitroxide Mediated Polymerization

 Milan Maric
Dept. of Chemical Engineering, McGill University

Milan Maric studied Chemistry (B.Sc.) and Chemical Engineering and Management (B.Eng.&Mgmt.) at McMaster University in Hamilton, Ontario, Canada.  He then pursued graduate studies working with Chris Macosko at the University of Minnesota-Twin-Cities in the area of compatibilization of thermoplastic/silicone blends, earning his Ph.D. in 1999.  He then worked in the Scale-up Engineering Group at the Xerox Research Centre of Canada (XRCC) from 1999-2003 and subsequently joined McGill University in 2003 as an Assistant Professor in the Department of Chemical Engineering and was promoted to Associate Professor in 2009.  Maric’s research group principally focuses on the application of nitroxide mediated polymerization to develop functional materials for a wide range of applications such as block copolymer surfactants, membrane/barrier materials, conductive copolymers and stimuli-responsive polymers.

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Controlled radical polymerization (CRP) has been one of the most significant breakthroughs in polymer chemistry over the past 20 years.  These free radical polymerization processes display outwardly the features of truly “living” polymerizations (narrow molecular weight distribution and active chain ends) without the need for scrupulously clean reagents and air-free transfers.   Many variants have been developed; with some such as atom transfer polymerization (ATRP) and reversible addition fragmentation transfer polymerization (RAFT) becoming the most common.  Nitroxide mediated polymerization (NMP), despite being one of the first CRP methods developed, has lagged until recently, being revived by alkoxyamine initiators such as BlocBuilder (Arkema).  We will present our work with BlocBuilder to synthesize poly(methacrylates), which were not possible with first-generation nitroxides.  Specifically, we will describe the application of a low fraction of a co-monomer, 9-(4-vinylbenzyl)-9H-carbazole (VBK), which enables control of a methacrylate, while also imparting electron-donating properties.  Characterization of the polymerization process and its application to functional materials (eg. water-soluble fluorescent copolymers) will be highlighted.