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

 -  Macromolecules, 30, p.2422-2428, 1997 .
<br/><br/> 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.