Poly(lactic acid): New catalysts, processes and materials

The degree and type of stereoregularity of polymers have a major effect on their physical and chemical properties and consequently on their possible applications. Poly(lactic acid) (PLA) is a biodegradable polymer prepared by the catalyzed ring opening polymerization of lactide. PLA of different stereoregularities may be formed by choice of the lactide stereoisomer(s) and choice of the catalyst. In addition, a truly living catalyst may enable the formation of stereoblock- and block-copolymers of PLA by sequential monomer addition.
In this presentation we will describe recent findings from our group, including: the design of new chelating ligands and their complexation tendencies around different metals; mechanistic studies related to dual-stereocontrol and polymeryl exchange between catalyst enantiomers; and exceptionally active and living/immortal polymerization catalysts. Employing these catalysts gave rise to tailor-made PLA materials, including: highly syndiotactic PLA, stereo-n-block copolymers of PLA, and block-stereoblock copolymers of PLA-PCL (poly(epsilon-caprolactone)) which exhibited unique thermal properties.