Macromolecular engineering of polylactones and polylactides. 19. Kinetics of ring-opening polymerization of epsilon-caprolactone initiated with functional aluminum alkoxides
[en] End-functional aliphatic polyesters have been synthesized by ring-opening polymerization (ROP) of epsilon-caprolactone (epsilon-CL) and lactides (LA). Polymerization initiated with any of the functional aluminum alkoxides of the general structure Et(3-p)Al(OCH(2)X)(p), where p = 1 and 3, obeys a living ''coordination-insertion'' mechanism, under suitable conditions (temperature, concentration, and solvent), with the formation of alpha-functional chains of a predictable molecular weight. A kinetic study has emphasized the importance of the cyclic monomer (epsilon-CL or LA) and the key role of the initiator structure: the number of functional alkoxides per aluminum and the nature of the functional group (X = CH2Br, (CH2)(2)CH=CH2, (CH2)(2)NEt(2)). Activation enthalpy and entropy have been calculated for the epsilon-CL polymerization initiated by several aluminum alkoxides at various temperatures. The effects of solvent (toluene or tetrahydrofuran) and purification of the aluminum monoalkoxides by distillation under reduced pressure have also been considered.
Research Center/Unit :
Center for Education and Research on Macromolecules (CERM)
Disciplines :
Materials science & engineering Chemistry
Author, co-author :
Dubois, Philippe ; Université de Liège - ULiège > Depatment of chemistry > Center for Education and Research on Macromolecules (CERM)
Ropson, Nathalie; Université de Liège - ULiège > Department of Chemistry > Center for Education and Research on Macromolecules (CERM)
Jérôme, Robert ; Université de Liège - ULiège > Department of Chemistry > Center for Education and Research on Macromolecules (CERM)
Teyssié, Philippe ; Université de Liège - ULiège > Department of Chemistry > Center for Education and Research on Macromolecules (CERM)
Language :
English
Title :
Macromolecular engineering of polylactones and polylactides. 19. Kinetics of ring-opening polymerization of epsilon-caprolactone initiated with functional aluminum alkoxides
Publication date :
11 March 1996
Journal title :
Macromolecules
ISSN :
0024-9297
eISSN :
1520-5835
Publisher :
Amer Chemical Soc, Washington, United States - Washington
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Bradley, D. C.; Mehrothra, R. C.; Gaur, D. P. Metal Alkoxides; Academic Press: London, 1978; Vol. 74, p 122.