[28] High-resolution 13C and 1H solution NMR study of poly(lactide)

K.A.M. Thakur, R.T. Kean, E. Hall, J. Kolstad, T. Lindgren, M.A. Doscotch, J.I. Siepmann, and E.J. Munson

Macromolecules 30, 2422-2428 (1997)

Publication 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.

High-resolution 13C and 1H solution NMR study of poly(lactide)