A single-atom upgrade to polydicyclopentadiene
Date
2024
Authors
Godwin, Benjamin
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Polydicyclopentadiene (PDCPD) is an engineering plastic produced through the ring-opening metathesis polymerization (ROMP) of dicyclopentadiene (DCPD), a petrochemical waste product. Owing to its high glass transition temperature, high storage modulus, high tensile strength, and general robustness to chemical or physical attack, PDCPD has enjoyed commercial use for making body panels for automobiles and heavy machinery. However, PDCPD is a simple polyolefin composed of only hydrogen and carbon atoms; it is thus low surface energy and not chemically tunable. The low surface energy also makes the application of paints and adhesives challenging.
Herein I describe a ketone-functionalized derivative of dicyclopentadiene (oxaDCPD). When polymerized oxaPDCPD displays a unique non-canonical hydrogen bond between the ketone and an adjacent vinyl hydrogen within the polymer. Partly as a result of this interaction, the thermoset polymer has an increased glass transition temperature, storage modulus, Young’s modulus, compression strength, and surface functionality compared to the native material. I also describe the copolymerization of dicyclopentadiene with the novel oxa-dicyclopentadiene monomer to produce copolymers. These copolymers display remarkably tunable (and improved) mechanical and thermal properties. Additionally, the copolymers have improved surface functionality and display resistance to oxidative embrittlement.
Many thermosets—including PDCPD and oxaPDCPD—are produced in a process called reaction injection molding (RIM) wherein neat monomer is directly transformed to solid polymer using a catalyst. In these polymerizations the crosslinks between the polymer chains form alongside the polymer, rapidly forming a solid. It is therefore challenging to study these kinds of processes. I have developed a method suitable for laboratory-scale studies of these reactions. This method is high-throughput and low cost. Remarkably, not only can various initiators be compared but the mechanical and thermal properties of the final material can be generally predicted.
Finally, despite PDCPD’s industrial niche remaining in the body panel market for decades there is a large volume of high-impact research dedicated to it. As part of a Natural Sciences and Engineering Research Council of Canada (NSERC) Lab to Market (L2M) Grant I conducted stakeholder interviews to determine industry pain points and determine a path towards commercialization of new PDCPD technologies.
Description
Keywords
metathesis, reaction injection molding, olefin, mechanical characterization