Rare earth metal tris(borohydride) complexes as initiators for epsilon-caprolactone polymerization: General features and IR investigations of the process
SOUM, Alain
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
SOUM, Alain
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
International Journal of Biological Macromolecules. 2005, vol. 38, n° 16, p. 6888-6894
Elsevier
English Abstract
Trivalent rare earth metal borohydride complexes Ln(BH4)(3)(THF)(3)(Ln = La, Nd, Sm) initiate the ring-opening polymerization of epsilon-caprolactone (epsilon-CL) to give, in quantitative yields and in a few minutes, ...Read more >
Trivalent rare earth metal borohydride complexes Ln(BH4)(3)(THF)(3)(Ln = La, Nd, Sm) initiate the ring-opening polymerization of epsilon-caprolactone (epsilon-CL) to give, in quantitative yields and in a few minutes, (x,(o-dihydroxytelechelic poly(epsilon-caprolactone) displaying a relatively narrow molar mass distribution (<= 1.3). The polymer features depend on both the metal and the solvent. A good agreement between (M) over bar (n(theo)) and (M) over bar (n(exp)) is observed for low [monomer](0/)[initiator](0) values whereas a deviation ((M) over bar (n(exp)), < (M) over bar (n(theo)) is obtained at higher ratios; this behavior has been rationalized by the occurrence of some transfer reactions. The gel formed during the polymerization arises from the involvement of the -(OBH2) end groups of the active polymer chains in several inter- and intramolecular van der Waals interactions, as revealed by in-depth infrared investigations of the various intermediates implicated in the whole polymerization mechanism. Finally, the polymers synthesized display only traces of residual nontoxic rare earth metals, thus making them suitable for biomedical applications.Read less <
English Keywords
BOROHYDRIDE
ELEMENTS
TRANSITION-METAL
CYCLIC ESTERS
LACTONES
RING-OPENING POLYMERIZATION
LIVING POLYMERIZATIONS
DELTA-VALEROLACTONE
LANTHANUM ISOPROPOXIDE
COPOLYMERIZATION
Origin
Hal imported