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Ring-expansion copolymerization of L-lactide and glycolide
- 1:1 Copolymerizations of glycolide (GL) and L-lactide (LA) is performed in bulk at 100°C and at 160°C with four cyclic tin catalysts. The resulting copolyesters are characterized by SEC measurements, 1H and 13C NMR spectroscopy and by MALDI TOF mass spectrometry. At 160°C and longer reaction time (22 h) nearly complete conversion of both monomers is achieved, and cyclic copolymers with nearly random sequences are formed. At shorter times (0.5-3.0 h, depending on catalyst) the conversion of LA is incomplete, and only cyclics having even numbers of lactyl units are obtained. At 100°C at 22 h again cycles mainly consisting of even numbered lactyl units are formed, but with even and odd numbers of glycolyl units. Copolymerization of lactide at 160°C with small amounts of GL show that formation of high Tm crystallites (Tm > 190°C) is hindered even when only > 2% of GL is added. For polyglycolide containing a smaller amount of lactide complete solubility in hexafluoroisopropanol is only1:1 Copolymerizations of glycolide (GL) and L-lactide (LA) is performed in bulk at 100°C and at 160°C with four cyclic tin catalysts. The resulting copolyesters are characterized by SEC measurements, 1H and 13C NMR spectroscopy and by MALDI TOF mass spectrometry. At 160°C and longer reaction time (22 h) nearly complete conversion of both monomers is achieved, and cyclic copolymers with nearly random sequences are formed. At shorter times (0.5-3.0 h, depending on catalyst) the conversion of LA is incomplete, and only cyclics having even numbers of lactyl units are obtained. At 100°C at 22 h again cycles mainly consisting of even numbered lactyl units are formed, but with even and odd numbers of glycolyl units. Copolymerization of lactide at 160°C with small amounts of GL show that formation of high Tm crystallites (Tm > 190°C) is hindered even when only > 2% of GL is added. For polyglycolide containing a smaller amount of lactide complete solubility in hexafluoroisopropanol is only observed around and above 20 mol% of lactide.…
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| Autor*innen: | Steffen WeidnerORCiD, H. R. Kricheldorf, F. Scheliga |
|---|---|
| Dokumenttyp: | Zeitschriftenartikel |
| Veröffentlichungsform: | Verlagsliteratur |
| Sprache: | Englisch |
| Titel des übergeordneten Werkes (Englisch): | Macromolecular Chemistry and Physics |
| Jahr der Erstveröffentlichung: | 2021 |
| Organisationseinheit der BAM: | 6 Materialchemie |
| 6 Materialchemie / 6.3 Strukturanalytik | |
| Veröffentlichende Institution: | Bundesanstalt für Materialforschung und -prüfung (BAM) |
| Verlag: | WileyVCH |
| Jahrgang/Band: | 22 |
| Ausgabe/Heft: | 3 |
| Erste Seite: | 307 |
| DDC-Klassifikation: | Naturwissenschaften und Mathematik / Chemie / Analytische Chemie |
| Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Ingenieurwissenschaften und zugeordnete Tätigkeiten | |
| Freie Schlagwörter: | Copolymerization; Crystallization; Glycolide; L-lactide; MALDI-TOF MS; Ring-expansion polymerization |
| Themenfelder/Aktivitätsfelder der BAM: | Chemie und Prozesstechnik |
| Material | |
| DOI: | 10.1002/macp.202000307 |
| URN: | urn:nbn:de:kobv:b43-520270 |
| ISSN: | 1022-1352 |
| Verfügbarkeit des Dokuments: | Datei für die Öffentlichkeit verfügbar ("Open Access") |
| Lizenz (Deutsch): |  Creative Commons - CC BY-NC-ND - Namensnennung - Nicht kommerziell - Keine Bearbeitungen 4.0 International |
| Datum der Freischaltung: | 21.01.2021 |
| Referierte Publikation: | Ja |
| Datum der Eintragung als referierte Publikation: | 21.01.2021 |
| Schriftenreihen ohne Nummerierung: | Wissenschaftliche Artikel der BAM |
