Activation mechanisms of trialkylaluminum in alkali metal alkoxides or tetraalkylammonium salts/propylene oxide controlled anionic polymerization
CARLOTTI, Stéphane
Laboratoire de Chimie des polymères organiques [LCPO]
Team 1 LCPO : Polymerization Catalyses & Engineering
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Laboratoire de Chimie des polymères organiques [LCPO]
Team 1 LCPO : Polymerization Catalyses & Engineering
CARLOTTI, Stéphane
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
Macromolecular Symposia. 2005, vol. 226, p. 61-68
Wiley-VCH Verlag
Resumen en inglés
The anionic polymerization of propylene oxide (PO) initiated by alkali metal alkoxides is in non polar solvents a very slow and non controlled reaction process. Transfer reaction to monomer is predominant, allowing only ...Leer más >
The anionic polymerization of propylene oxide (PO) initiated by alkali metal alkoxides is in non polar solvents a very slow and non controlled reaction process. Transfer reaction to monomer is predominant, allowing only the preparation of low molar masses PPO. The influence of the addition of trialkylaluminium to either an alkali metal alkoxide or a tetraalkylammonium salt used as initiator for PO polymerization in hydrocarbon media was investigated. A strong enhancement of the polymerization rate accompanied by a drastic decrease of the transfer reactions is observed, allowing the synthesis of PPO with well controlled molar masses. At constant monomer and alkali metal alkoxide concentrations, the polymerization rate increases with increasing trialkylaluminium concentration. Results indicate that the trialkylaluminium derivative is involved in the formation of two distinct complexes, one with the alkali metal alkoxide or the tetraalkylammonium salt and another one with the PO monomer which is strongly activated towards nucleophilic active species. Significant differences between the alkali metal and tetraalkylammonium based initiators are observed. In particular much less trialkylaluminum activator is needed with the ammonium salt to get the same rate of propagation and controlled polymerization.< Leer menos
Palabras clave en inglés
trialkylaluminum
monomer activation
polyethers
propylene oxide
anionic polymerization
Orígen
Importado de HalCentros de investigación