Colorado State University Research Foundation

Jian-Bo Zhu

Eugene Y Chen

The invention discloses a class of new polymers, trans-ring-fused poly(4-hydroxybutyrate)s (RF-P4HB) that exhibit a unique set of properties, including robust thermal stability and mechanical strength, quantitative recyclability to the building block monomers via thermolysis and/or chemical catalysis, and convenient production from the chemical ring-opening polymerization under ambient temperature and pressure. Another unique property is the formation of crystalline stereocomplexed polymers with high melting temperature upon mixing the two enantiomeric RF-P4HB chains via stereocomplexing co-crystallization. This invention also provides the corresponding ring-fused lactone monomer structures that enable the synthesis of the RF-P4HB polymers, through trans-fusing of rings to the parent &#x3b3;-butyrolactone ring. Furthermore, a polymerization or copolymerization process for the synthesis of RF-P4HB polymers and copolymers is disclosed.

Recyclable polymers based on ring-fused gamma-butyrolactones

B/N Lewis pairs have been discovered to catalyze rapid epimerization of meso-lactide (LA) or LA diastereomers quantitatively into rac-LA. The obtained rac-LA can be kinetically polymerized into poly(-lactide) and optically resolved-LA, with a high stereoselectivity factor k/kof 53 and an ee value of 91% at 50.6% monomer conversion, by a bifunctional chiral catalyst. The epimerization and enantioselective polymerization can be coupled into a one-pot process for transforming meso-LA directly into poly(-lactide) and-LA.

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Ft. Collins, CO, United States of America

Jian-Bo Zhu