Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/34362
標題: Ring-opening polymerization of lactide initiated by magnesium and zinc alkoxides
作者: Wu, J.C.
林助傑
Huang, B.H.
Hsueh, M.L.
Lai, S.L.
Lin, C.C.
關鍵字: magnesium
L-lactide
ring opening polymerization
epsilon-caprolactone
racemic lactide
stereoselective polymerization
immortal polymerization
efficient catalysts
ligand
complexes
stereocontrol
mechanism
kinetics
期刊/報告no:: Polymer, Volume 46, Issue 23, Page(s) 9784-9792.
摘要: A mono methylether Salen-type ligand, SalenMe-H (1) is prepared in a one flask reaction by condensation of trans-1,2-diaminocyclohexane with 2-methoxybenzenaldehyde and followed by the addition of 2,4-di-tert-butylsalicylaldehyde. Further reaction of 1 with Mg(OBn)(2) in THF produces a magnesium alkoxide, [(SalenMe)Mg(OBn)](2) (2). Compound 1 reacts with ZnEt2 yields monomeric complex (SalenMe)ZnEt (3), which further reacts with 1 molar equiv of benzyl alcohol giving [(SalenMe)Zn(OBn)](2) (4). Experimental results show that complexes 2 and 4 efficiently initiate the ring-opening polymerization of L-lactide and rac-lactide in a controlled fashion, yielding polymers with very low polydispersity indexes. Kinetic studies show a second-order dependency on [LA] and a first-order on [2] with magnesium complex 2 as an initiator. While zinc complex 4 is used as an initiator, the polymerization rate has a first order dependency on both [LA] and [4]. (c) 2005 Elsevier Ltd. All rights reserved.
URI: http://hdl.handle.net/11455/34362
ISSN: 0032-3861
文章連結: http://dx.doi.org/10.1016/j.polymer.2005.08.009
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