Interest in biomass-derived polymers is growing, in particular to avoid using our limited fossil resources. One class of renewable polymers that was intensively studied are poly(hydroxyalkanoate)s including poly(3-hydroxybutyrate) (PHB). Beyond natural production of PHB by microorganisms, PHB can be synthesized by a chemical route via ring-opening polymerization (ROP) of racemic β-butyrolactone (BBL). The fact that BBL can be prepared from carbon dioxide opens up an opportunity for sustainable chemical synthesis, however, despite the high internal strain of the four-membered ring, BBL is a reluctant monomer and is much less reactive than lactide or ε-caprolactone. Yttrium complexes bearing dianionic ligands are versatile species for catalyzing the ROP of BBL regarding their activity and stereospecificity. Apart from carbon dioxide, an important class of renewable resources are cyclic terpenes including derivates such as (-)-menthone or (-)-carvone. The derived lactones (-)-menthide (M), carvomenthide (CM) and dihydrocarvide (DHC) were used for synthesizing the first renewable terpene-based polyesters produced by yttrium-mediated ROP. Another biomass-derived monomer is pentadecalactone (PDL). It is a naturally occurring macrolactone and a synthetic musk, generally used in enzyme-catalyzed polymerization, which was successfully polymerized using yttrium-mediated polymerization. As highly stereoregular PHB obtained with the respective yttrium catalysts fractures at low strains, stress-strain properties were improved by synthesizing block copolymers from PHB, terpene-based monomers and PDL with regard to their coordination-strength to the metal center by facile sequential addition of monomers. Additionally, yttrium-mediated ROP of DHC led to polymers with double bonds in the polymer units. Using thiol-ene reactions, copolymers were functionalized to tune stress-strain properties and amphiphilic behavior.

From 4- to 16-membered rings: Biomass-derived, tailor-made copolymers from “hard-to-polymerize” lactones via yttrium-mediated ring-opening polymerization

Where thousands of chemistry professionals meet to share ideas and advance scientific and technical knowledge. Spring 2023 abstracts, posters, and presentations will launch at the end of March.

ACS Spring 2023

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.