Crystal Structure and Morphology of Poly(l-lactide-b-d-lactide) Diblock Copolymers

Li, Liangbin and Zhong, Zhiyuan and Jeu de, Wim H. and Dijkstra, Pieter J. and Feijen, Jan (2004) Crystal Structure and Morphology of Poly(l-lactide-b-d-lactide) Diblock Copolymers. Macromolecules, 37 (23). pp. 8641-8646. ISSN 0024-9297

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Abstract:	The isothermal crystallization behavior of low-molecular-weight (DP 50) poly(l-lactide-b-d-lactide) diblock copolymers is reported, as studied by small- and wide-angle X-ray scattering. The symmetric diblock copolymer crystallizes in the stereocomplex form for the whole range of crystallization temperatures, while the one with a block ratio of 80/20 grows into homocrystallites. For an intermediate block ratio (66/33), the stereocomplex form is obtained at high crystallization temperatures while a coexistence region with homocrystal phase exists at low temperatures. In addition to the transition enthalpy, size effects and kinetic routes play a role in the competition between the stereocomplex and the homocrystalline forms. The lamellar spacing (long period and crystal thickness) shows a different temperature dependence for the three diblock copolymers, which is discussed in relation to the specific morphology and molecular constitution.
Item Type:	Article
Copyright:	ACS
Faculty:	Science and Technology (TNW)
Research Group:	Polymer Chemistry and BioMaterials (PBM)
Link to this item:	http://purl.utwente.nl/publications/71378
Official URL:	http://dx.doi.org/10.1021/ma049077o
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