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Controlled Ring‐Opening Polymerization of Lactones and Lactide Initiated by Lanthanum Isopropoxide, 2 . Mechanistic Studies
Author(s) -
Save Maud,
Soum Alain
Publication year - 2002
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200290043
Subject(s) - alkoxide , polymerization , lanthanum , ring opening polymerization , polymer chemistry , chemistry , monomer , lactide , polymer , intramolecular force , organic chemistry , catalysis
The mechanism of ring‐opening polymerization of some lactones and lactide initiated by lanthanum isopropoxide has been comprehensively investigated. NMR and viscosity analyses demonstrated that three active polymer chains grow per lanthanum atom and that, depending on the coordinating ability of the monomer, propagation proceeds on aggregated or unaggregated active species. It is also demonstrated that inter‐ and intramolecular side reactions are limited and that lanthanum‐based initiator selectivity in ring‐opening polymerization is analogous to that of aluminum ones.Part of the proposed mechanism for the lanthanum alkoxide initiated polymerization of ε ‐caprolactone.