Authors Pospiech, D. ; Komber, H. ; Jehnichen, D. ; Häußler, L. ; Eckstein, K. ; Scheibner, H. ; Janke, A. ; Kricheldorf, H.R. ; Petermann, O.
Title Multiblock Copolymers of L-Lactide and Trimethylene Carbonate
Date 05.04.2005
Number 12256
Abstract Sequential copolymerizations of trimethylene carbonate (TMC) and <FONT SIZE="-1">L</FONT>-lactide (LLA) were performed with2,2-dibutyl-2-stanna-1,3-oxepane as a bifunctional cyclic initiator. The block lengths were varied via themonomer/initiator and via the TMC/<FONT SIZE="-1">L</FONT>-lactide ratio. The cyclic triblock copolymers were transformed in situinto multiblock copolymers by ring-opening polycondensation with sebacoyl chloride. The chemicalcompositions of the block copolymers were determined from <SUP>1</SUP>H NMR spectra. The formation of multiblockstructures and the absence of transesterification were proven by <SUP>13</SUP>C NMR spectroscopy. Differential scanningcalorimetry (DSC), wide-angle X-ray scattering (WAXS), and dynamic mechanical analysis (DMA)measurements confirmed the existence of a microphase-separated structure in the multiblock copolymersconsisting of a crystalline phase of poly(LLA) blocks and an amorphous phase formed by the poly(TMC)blocks. Stress-strain measurements showed the elastomeric character of these biodegradable multiblockcopolymers, particularly in copolymers having <IMG SRC="/images/gifchars/epsilon.gif" BORDER=0 >-caprolactone as comonomer in the poly(TMC) blocks.
Publisher Biomacromolecules
Citation Biomacromolecules 6 (2005) 439-446
Tags ring-opening polymerization macrocyclic polymerization epsilon-caprolactone polymers behavior polylactones polyesters elastomers lactones blends

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