No matter the order of monomer addition for the synthesis of well-defined block copolymers by sequential group transfer polymerization using N-heterocyclic carbenes as catalysts
TATON, Daniel
Laboratoire de Chimie des Polymères Organiques [LCPO]
Team 1 LCPO : Polymerization Catalyses & Engineering
< Leer menos
Laboratoire de Chimie des Polymères Organiques [LCPO]
Team 1 LCPO : Polymerization Catalyses & Engineering
Idioma
en
Article de revue
Este ítem está publicado en
Polymer Chemistry. 2011, vol. 2, n° 8, p. 1706-1712
Royal Society of Chemistry - RSC
Resumen en inglés
Unsaturated N-heterocyclic carbenes (NHCs) such as 1,3-bis(di-isopropyl)imidazol-2-ylidene (1) and 1,3-bis(di-tert-butyl)imidazol-2-ylidene (2) are shown to catalyze the sequential group transfer polymerization (GTP) of ...Leer más >
Unsaturated N-heterocyclic carbenes (NHCs) such as 1,3-bis(di-isopropyl)imidazol-2-ylidene (1) and 1,3-bis(di-tert-butyl)imidazol-2-ylidene (2) are shown to catalyze the sequential group transfer polymerization (GTP) of (meth) acrylic monomers. A variety of block copolymers including not only alkyl methacrylate but also alkyl acrylate monomer units as well as blocks deriving from N,N-dimethylacrylamide and methacrylonitrile were thus obtained at room temperature, using 1-methoxy-2-methyl-1-trimethylsiloxypropene (MTS) as initiator in THF as solvent. Block copolymerizations could be achieved, starting indifferently from the GTP of the acrylic monomer to that of the methacrylic one or vice versa, that is, regardless of the order of addition of the two monomers, in contrast to most examples of block copolymer synthesis by "controlled/living" sequential polymerization. It is postulated that these NHC-catalyzed GTPs of (meth) acrylics proceed via a single step concerted-like associative mechanism, involving the formation of thermodynamically unstable intermediates or transition states, likely hypervalent siliconates, with no detectable anionic enolates formed.< Leer menos
Palabras clave en inglés
RING-OPENING POLYMERIZATION
TRANSFER RADICAL POLYMERIZATION
LIVING POLYMERIZATION
(METH)ACRYLIC MONOMERS
POLY(ETHYLENE OXIDE)S
ETHYLENE-OXIDE
REACTIVITY
INITIATORS
POLYMERS
METHACRYLATES
Orígen
Importado de HalCentros de investigación