| Stereocomplex formation between enantiomeric poly(lactic acid)s. 12. spherulite growth of low-molecular-weight poly(lactic acid)s from the melt. | |
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MedLine Citation:
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PMID: 15244428 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The spherulite growth of stereocomplex crystallites in the blend from low-molecular-weight poly(L-lactide) [i.e., poly(L-lactic acid) (PLLA)] and poly(D-lactide) [i.e., poly(D-lactic acid) (PDLA)] from the melt, together with that of the homocrystallites in pure PLLA and PDLA films, was investigated using polarization optical miscroscopy. The spherulite growth of stereocomplex crystallites occurred at a wider temperature range (</=190 degrees C) compared with that of homocrystallites (</=140 degrees C). At 140 degrees C, the spherulite radius growth rate (G) for the stereocomplex crystallites (136.4 microm min(-1)) was an order of magnitude higher than those for the homocrystallites of PLLA (11.8 microm min(-1)) and PDLA (15.7 microm min(-1)), whereas the induction period was shorter for the spherulties of stereocomplex crystallites (0.0 min) than for the spherulties of homocrystallites of PLLA (2.6 min) and PDLA (0.7 min). In addition to these two factors, the higher spherulite density of stereocomplex crystallites compared with those of the homocrystallites of PLLA and PDLA resulted in rapid completion of overall crystallization of stereocomplex. The front factor (G(0)) and nucleation constant (K(g)) for the stereocomplex crystallites in the temperature range of 140-190 degrees C were estimated to be 3.56 x 10(12) microm min(-1) and 8.42 x 10(5) K(2), respectively. The G(0) value for stereocomplex crystallites was 1 and 2 orders of magnitude higher than those for the homocrystallites of PLLA (9.69 x 10(11) microm min(-1)) and PDLA (8.79 x 10(10) microm min(-1)), whereas the K(g) value for stereocomplex crystallites was twice those for the homocrystallites of PLLA (4.95 x 10(5) K(2)) and PDLA (4.20 x 10(5) K(2)). |
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Authors:
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Hideto Tsuji; Yasufumi Tezuka |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Biomacromolecules Volume: 5 ISSN: 1525-7797 ISO Abbreviation: Biomacromolecules Publication Date: 2004 Jul-Aug |
Date Detail:
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Created Date: 2004-07-12 Completed Date: 2005-02-09 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 100892849 Medline TA: Biomacromolecules Country: United States |
Other Details:
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Languages: eng Pagination: 1181-6 Citation Subset: IM |
Affiliation:
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Department of Ecological Engineering, Faculty of Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi, Aichi 441-8580, Japan. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Biocompatible Materials
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chemical synthesis*,
chemistry Crystallization Lactic Acid / chemical synthesis*, chemistry Macromolecular Substances / chemistry Molecular Weight Photomicrography / methods Polyesters / chemical synthesis, chemistry Polymers / chemical synthesis*, chemistry Stereoisomerism Temperature |
| Chemical | |
Reg. No./Substance:
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0/Biocompatible Materials; 0/Macromolecular Substances; 0/Polyesters; 0/Polymers; 26100-51-6/poly(lactic acid); 26969-66-4/poly(lactide); 50-21-5/Lactic Acid |
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