[article]
| Titre : |
Development of a direct polycondensation process for poly (L-lactic acid) |
| Type de document : |
texte imprimé |
| Auteurs : |
T. Fukushima, Auteur ; Y. Sumihiro, Auteur ; K. Koyanagi, Auteur ; N. Hashimoto, Auteur ; Y. Kimura, Auteur ; T. Sakai, Auteur |
| Année de publication : |
2000 |
| Article en page(s) : |
p. 380-385 |
| Note générale : |
Bibliogr. |
| Langues : |
Anglais (eng) |
| Index. décimale : |
668.9 Polymères |
| Résumé : |
Reactive extrusion - Poly(L-lactic acid) (PLLA) is quite promising for use as biodegradable and non-petroleum derived plastics. In this study we developed an innovative two-step polycondensation process so as to produce economically PLLA with high molecular weight. The process is composed of both melt polycondensation under the lactide-reflux and solid-phase polycondensation. First we studied a direct polycondensation of L-lactic acid with a small amount of solvent, using a mixture of L-lactic acid as raw material, diphenyl ether as solvent, Tin (II) chloride dihydrate as catalyst, and p-toluene sulfonic acid as a discoloration prevention agent. After the dehydrative oligomerization of L-lactic acid, the polycondensation of the oligocondensates and solid-phase post-polycondensation, PLLA of Mw=266,000 could be obtained. Then, we carried out direct bulk polycondensation tests from L-lactic acid without any solvent added. After optimization of the reaction conditions, PLLA with Mw=134,000 was successfully produced by the melt-polycondensation of L-lactic acid accompanied by solid-phase post-poly-condensation. In both systems, the lactide-reflux was indispensable for promoting dehydration/water removal. The refluent lactide was taken into the polymer-chain by trans-esterification reaction during the melt-polycondesation. Furthermore, the catalyst was allowed to deactivate and stabilize during the solid-phase polymerization to cause the Mw growth. |
| Note de contenu : |
- EXPERIMENTAL : Reagents - Polymerization - Analyses - Two-step polycondensation process from melt to solid phase - Polycondensation process without solvent
- RESULTS AND DISCUSSIONS : Polycondensation using with a batch-type reactor - Additive effects on the melt and solid-phase polycondensation - Bulk polycondensation process without solvent on laboratory-scale - A proposal for a direct molding system |
| DOI : |
10.3139/217.1615 |
| En ligne : |
https://drive.google.com/file/d/17VCepKi2iohXiM6ln4FxwuBGeB79spkm/view?usp=drive [...] |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=16156 |
in INTERNATIONAL POLYMER PROCESSING > Vol. XV, N° 4 (12/2000) . - p. 380-385
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