The major volatile component of conifer tree sap is α-pinene (~70% of volatile terpene content on average.). Therefore α-pinene is an abundant, bio-sourced, and inedible chemical feedstock that can be harvested non-destructively from pine trees. Additionally, the all-hydrocarbon structure of terpenes makes them sought-after candidates for the synthesis of new polyolefin materials. To date, the trisubstituted and sterically congested olefin of α-pinene renders it a notoriously difficult monomer to polymerize through various methods. While density functional theory calculations suggest α-pinene is sufficiently strained, ring opening metathesis polymerization (ROMP) has been unsuccessful, owing to this steric congestion near the cycloolefin. When I was a Post-Doc with Marc and Frank at UMN, my research project involved neither sustainable polymers nor ROMP, making me feel sometimes left out. I therefore got my own laboratory to explore what might have been. We envisioned that isomerization of α-pinene to δ-pinene, which features a more accessible disubstituted olefin may afford a new monomer capable of ROMP. We discovered that δ-pinene undergoes ROMP to high conversion (&gt;95%), high molar mass (70 kDa), and in highly controlled fashion (D &lt; 1.3) using Grubbs’ 3<sup>rd</sup> generation catalyst.  Mechanistic details on ROMP and some investigations on material properties of this new polyolefin will be discussed. Marc may or may not be impressed.

Marc likes biomass-based polymers and ROMP: So here’s both

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

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