CPOS Seminar: "Degradable materials design and deconstruction: Catalytic strategies towards polyethylene sustainability"

Speaker: Maximilian Baur, Postdoctoral Researcher, Scott Research Group, Department of Chemical Engineering, UC Santa Barbara 

Polyethylene has claimed the status of the most important synthetic polymer, playing a vital role in technology and everyday life. However, its uniform molecular structure, composed of chemically inert hydrocarbon chains, lacks efficient chain scission pathways for degradation and recycling. Polyethylene therefore contributes a substantial share to the environmental burden of persistent plastic waste. Catalytic strategies can be leveraged to alleviate these drawbacks and improve polyethylene sustainability, particularly regarding degradability and carbon circularity: New, degradable polyethylene materials can be synthesized by catalytic copolymerization of ethylene with carbon monoxide, which introduces in-chain carbonyl groups that act as predetermined breaking points. These render the materials degradable while preserving the other desirable materials properties of conventional polyethylene.

   Additionally, catalytic upcycling strategies can enable carbon circularity via deconstruction of post-consumer polyethylene waste into value-added chemicals. Tandem catalytic hydrogenolysis-aromatization allows the breakdown of polyethylene to alkylbenzenes, key intermediates for the synthesis of anionic surfactants. Varying the catalyst support acidity and the polyethylene feedstock allows tailoring the molecular structure of the obtained alkylbenzenes to potentially modify the specific materials properties of the final surfactant products.

   This combination of different catalytic approaches spans the entire lifecycle of polyethylene from synthesis to deconstruction and can help to improve the overall sustainability of this important material.