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Polylactones, 38. Polymerization of L-lactide with Fe(II) lactate and other resorbable Fe(II) salts

✍ Scribed by Hans R. Kricheldorf; Dirk-Olaf Damrau

Publisher
John Wiley and Sons
Year
1997
Tongue
English
Weight
409 KB
Volume
198
Category
Article
ISSN
1022-1352

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✦ Synopsis

Abstract

Commercial FeCl~2~ and Fe(II) glycolate, Fe(II) L‐lactate or Fe(II) L‐mandelate were used as initiators for the polymerization of L‐lactide. All polymerizations were conducted in bulk at 150°C, because no conversion was observed in bulk at 120°C. The Fe(II) lactate was found to be more reactive than FeCl~2~, and it yielded slightly higher molecular weights than all other initiators. Under the optimum conditions, viscosity average molecular weights (M̄~v~) around 50 000 and yields above 90% were obtained. However, slight racemization (2–5%) of the isolated poly(L‐lactide) was also observed under most circumstances. Characterization of unreacted monomer proved that the racemization mainly involves the monomeric lactide due to its higher CH acidity.

📜 SIMILAR VOLUMES

Polylactones, 37. Polymerizations of L-l
Polylactones, 37. Polymerizations of L-lactide initiated with Zn(II) L-lactate and other resorbable Zn salts
✍ Hans R. Kricheldorf; Dirk-Olaf Damrau 📂 Article 📅 1997 🏛 John Wiley and Sons 🌐 English ⚖ 668 KB

## Abstract Zn(II) L‐lactate (ZnLac~2~) was prepared either from ZnO and ethyl L‐lactate or with slightly higher optical purity from ZnO and L‐lactide. Using water‐free ZnLac~2~ L‐lactide was polymerized in bulk at 120°C or 150°C. Higher yields and higher molecular weights were found at 150°C. The