Cited by 149biodegradable polymer synthesis and propertiesAdvanced Polymer Synthesis and CharacterizationPolymer crystallization and properties

Polylactones, 19. Anionic polymerization of L‐lactide in solution

Kricheldorf, Hans R., Kreiser‐Saunders, Ingrid·1990·Die Makromolekulare Chemie

Abstract

The anionic polymerization of L‐lactide was studied with four potential initiators of different basicity: potassium benzoate, potassium phenoxide, potassium tert‐butoxide and butyllithium. Regardless of the solvent, only the two most basic initiators proved to be reactive enough to initiate and maintain the polymerization. This result and the formation of benzyloxy end‐groups upon addition of benzyl bromide prove that the polymerizations proceed via alkoxide chain ends. Absence of initiator fragments in the isolated polylactide chains suggests that initiation mainly involves deprotonation of L‐lactide, whereas nucleophilic substitution only occurs to a minor extent. Furthermore, optical rotation measurements indicate that both the initiator and the alkoxide chain end cause partial racemization regardless of solvent and temperature. Furthermore, it was found that reagents such as triethylamine, pyridine or potassium benzoate which are not reactive enough to initiate polymerization, are basic enough to cause partial racemization of L‐lactide by deprotonation.

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Registry

Crossref · 10.1002/macp.1990.021910508

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  • Alkali metal complexes such as butyllithium and potassium methoxide can mediate anionic ROPs via a nucleophilic or enolate-type initiating mechanism.

    “Alkali metal complexes such as butyllithium 285 and potassium methoxide 286 can mediate anionic ROPs via a nucleophilic or enolate-type initiating mechanism.”

    From Catalysis as an Enabling Science for Sustainable Polymers (2018) · cites this paper as [285]

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Authors
Kricheldorf, H. R., & Kreiser‐Saunders, I.
Affiliations
Universität Hamburg (DE)
Corresponding author
Kricheldorf, Hans R.
Venue
Die Makromolekulare Chemie
Publisher
Wiley
Published
1990-05
Volume
191
Issue
5
Pages
1057-1066
ISSN
0025-116X (ISSN-L)
OpenAlex
W1588514918
Cited by
149
References
18
Citations by year
2026: 3 · 2025: 4 · 2024: 3 · 2023: 6 · 2022: 4 · 2021: 2 · 2020: 6 · 2019: 5 · 2018: 2 · 2017: 6 · 2016: 4 · 2015: 5 · 2014: 7 · 2013: 1 · 2012: 6
FWCI
2.25
Type
journal article
Language
en
Open access
closed
Locations
Die Makromolekulare Chemie (publishedVersion)
Topics
  • Physical Sciences › Materials Science › Biomaterials › biodegradable polymer synthesis and properties
  • Physical Sciences › Chemistry › Organic Chemistry › Advanced Polymer Synthesis and Characterization
  • Physical Sciences › Materials Science › Polymers and Plastics › Polymer crystallization and properties
Keywords
L-lactide, anionic polymerization, polylactic acid, potassium tert-butoxide, butyllithium, potassium phenoxide, potassium benzoate, deprotonation, nucleophilic substitution, racemization, optical rotation, benzyl bromide, solvent effects

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