Combination of an anionic terminator multifunctional initiator and divergent carbanionic polymerization: Application to the synthesis of dendrimer-like polymers and of asymmetric and miktoarm stars
GNANOU, Yves
Laboratoire de Chimie des polymères organiques [LCPO]
Team 1 LCPO : Polymerization Catalyses & Engineering
Laboratoire de Chimie des polymères organiques [LCPO]
Team 1 LCPO : Polymerization Catalyses & Engineering
GNANOU, Yves
Laboratoire de Chimie des polymères organiques [LCPO]
Team 1 LCPO : Polymerization Catalyses & Engineering
< Reduce
Laboratoire de Chimie des polymères organiques [LCPO]
Team 1 LCPO : Polymerization Catalyses & Engineering
Language
en
Article de revue
This item was published in
Journal of the American Chemical Society. 2008, vol. 130, n° 4, p. 1350-1361
American Chemical Society
English Abstract
A new and versatile synthetic strategy that provides access to precisely defined and totally soluble multicarbanionic initiators has been implemented to obtain by divergent growth dendrimer-like samples of polystyrene (PS) ...Read more >
A new and versatile synthetic strategy that provides access to precisely defined and totally soluble multicarbanionic initiators has been implemented to obtain by divergent growth dendrimer-like samples of polystyrene (PS) (up to the seventh generation) or polybutadiene (PB) (up to the third generation) and also asymmetric and miktoarm stars. This strategy rests on lithium-halide exchange reactions to generate multicarbanionic species and on the design of an original reagent that can concomitantly react with living carbanionic chains/arms to deactivate them and produce multicarbanionic sites after exchange of its bromides against lithium. This reagent, 4,4'-dibromodiphenylethylene (1), functions as a TERminating agent and a Multifunctional INItiator (TERMINI), according to a concept first proposed by Percec in another context. Upon using this anionic TERMINI in living carbanionic polymerization and repeating the two steps of chain end derivatization by 1 and divergent arm growth from the multifunctional sites generated, perfectly defined dendrimer-like polystyrene and polybutadiene could be obtained up to the seventh generation for the former and up to the third generation for the latter. Each step, i.e., chain end modification and arm growth, was carefully monitored, and the dendrimer-like samples of PS and PB were all characterized by size exclusion chromatography equipped with a multiangle laser light scattering detector (SEC/LS) and high-temperature size exclusion chromatography equipped with a viscometric detector (HT-SEC). The viscosity behavior of these dendrimer-like polystyrenes-bell-shaped variation versus the number of generation-was found to be similar to that reported for regular dendrimers. This chemistry, namely this anionic TERMINI, was also exploited to derive three-arm asymmetric and miktoarm stars.Read less <
English Keywords
POLYBUTADIENE
MACROMOLECULES
POLY(ETHYLENE OXIDE)S
SURFACE-PROPERTIES
BLOCK-COPOLYMERS
POLYSTYRENE
LIVING RADICAL POLYMERIZATION
CONVENTIONAL MONOMERS
BEHAVIOR
CHAIN
Origin
Hal imported