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Article

High-Resolution ¹³C and ¹H Solution NMR Study of Poly(lactide)

Khalid A. M. Thakur,* Robert T. Kean, Eric S. Hall, Jeffrey J. Kolstad, and Tim A. Lindgren

Cargill Incorporated, Central Research, P.O. Box 5699, Minneapolis, Minnesota 55440

Matthew A. Doscotch, J. Ilja Siepmann, and Eric J. Munson*

Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455

Macromolecules, 1997, 30 (8), pp 2422–2428

DOI: 10.1021/ma9615967

Publication Date (Web): April 21, 1997

In papers with more than one author, the asterisk indicates the name of the author to whom inquiries about the paper should be addressed.

Abstract

High-resolution 500 MHz solution-state ¹H and ¹³C NMR spectra of various poly(lactides) indicate at least hexad stereosequence sensitivity. The poly(lactides) were prepared in vials by melt polymerization of various combinations of l-lactide, d-lactide, and meso-lactide at 180 °C for 3 h using tin(II) bis(2-ethylhexanoate) (tin(II) octoate) as the catalyst in a 1:10 000 ratio. The intensity distribution of the various stereosequence resonances in the NMR spectra indicates a preference for syndiotactic addition during the polymerization process. Minimal evidence of transesterification was observed for these polymerization conditions.

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History

Published In Issue April 21, 1997
Received October 28, 1996
Revised Manuscript Received January 15, 1997

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Article

High-Resolution ¹³C and ¹H Solution NMR Study of Poly(lactide)