Poly(lactic acid) (PLA) is a biodegradable polymer prepared by the catalyzed ring opening polymerization of lactide. An ideal catalyst should enable a sequential polymerization of the lactide enantiomers to afford stereoblock copolymers with predetermined number and lengths of blocks. We recently introduced a new family of magnesium based catalysts that combine extremely high activity with living nature, which gives access to PLA materials of unprecedented microstructures. Full consumption of thousands of equivalents of L-LA within minutes gave PLLA of expected molecular weights and narrow molecular weight distributions. Precise PLLA-<i>b</i>-PDLA diblock copolymers having block lengths of up to 1000 repeat units were readily prepared within 30 min, and their thermal characterization revealed a stereocomplex phase only with very high melting transitions, melting enthalpies and degradation temperatures. The one pot sequential polymerization was extended up to precise hexablocks having ‘dialed-in’ block lengths which have not been reported before. These truly-living catalysts may open the way to next-generation PLA-based materials having vast potential for applications in material science.<br/>

Tailor-made stereo-n-blocks copolymers of poly(lactic acid) by living polymerization catalysts

254th National Meeting (2017)

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