[en] Three-arm star-branched aliphatic polyesters have been synthesized by an appropriate termination reaction of the living chains prepared by ring-opening polymerization with aluminum alkoxides. The use of functional aluminum alkoxides, Et2AlOCH2X with X = CH2CH2CH=CH2 and (CH2)10Br, has led to X functional end-capped star-branched polyesters. Trimesic acid trichloride has proved to be an efficient termination agent for the living poly(epsilon-caprolactone) [PCL] chains ended with a reactive aluminum alkoxide group. A quantitative end functionalization has been reported for bromide and 1-pentene end-capped star-branched PCL. The bromide end groups have been converted into azido end groups, which have been subsequently reduced to the expected primary amine end-capped star-branched PCL by catalytic transfer hydrogenation in DMF. In contrast to living PCL, reaction of trimesic acid chloride with the aluminum alkoxide end group of living poly(L,L)lactide [P(L,L)LA] and living poly(epsilon-caprolactone-b-(L,L)lactide) [P(CL-b-(L,L)LA] chains has produced star-branched polyesters within a very poor yield. This result is more likely due to a steric effect of the methyl group in a-position of the terminal aluminum alkoxide. This drawback has been overcome to some extent by initiating the living polymerization of (L,L)LA with primary amine end-capped star-branched PCL in the presence of triethylaluminum. Formation of a hydroxyl end-capped star-branched poly(epsilon-caprolactone-b-(L,L)lactide) diblock copolymer has accordingly been reported.
Research center :
Center for Education and Research on Macromolecules (CERM)
Disciplines :
Materials science & engineering Chemistry
Author, co-author :
Tian, Dong; Université de Liège - ULiège > Department of Chemistry > Center for Education and Research on Macromolecules (CERM)
Dubois, Philippe; 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. 18. Synthesis of star-branched aliphatic polyesters bearing various functinal end groups
Publication date :
18 July 1994
Journal title :
Macromolecules
ISSN :
0024-9297
eISSN :
1520-5835
Publisher :
American Chemical Society, Washington, United States - District of Columbia
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