Polymerization of l-lactide with SnCl2: A Low Toxic and Eco-friendly Catalyst

Polymerizations of l -lactide catalyzed either by neat SnCl 2 or by SnCl 2  + difunctional cocatalysts were conducted in bulk at 180, 160 and 140 °C with variation of the Lac/Cat ratio and time. With neat SnCl 2 poly(L-lactide) having weight average molecular weights (uncorrected M w ’s) up to 190 0...

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Bibliographic Details
Published in:Journal of polymers and the environment Vol. 29; no. 8; pp. 2504 - 2516
Main Authors: Kricheldorf, Hans R., Weidner, Steffen M.
Format: Journal Article
Language:English
Published: New York Springer US 01-08-2021
Springer Nature B.V
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Summary:Polymerizations of l -lactide catalyzed either by neat SnCl 2 or by SnCl 2  + difunctional cocatalysts were conducted in bulk at 180, 160 and 140 °C with variation of the Lac/Cat ratio and time. With neat SnCl 2 poly(L-lactide) having weight average molecular weights (uncorrected M w ’s) up to 190 000 g mol −1 were obtained mainly consisting of linear chains. Addition of salicylic acid or 1,1-bisphenol yielded a higher fraction of cyclic polylactides but lower molecular weights. Furthermore, SnCl 2 was compared with Bu 2 SnCl 2 and various other metal chlorides and the best results were obtained with SnCl 2 . With ethyl L-lactate as initiator SnCl 2 -catalyzed ROPs were performed at 120 °C and the lac/initiator ratio was varied. All these experiments were conducted under conditions allowing for comparison with ROPs catalyzed with neat Sn(II)-2-ethyhexanoate. Such a comparison was also performed with ε-caprolactone as monomer.
ISSN:1566-2543
1572-8919
DOI:10.1007/s10924-020-02042-w