(173t) Influence of Polymer Architecture on Catalytic Deconstruction of Polyethylene

Catalytic deconstruction has emerged as a promising solution to valorize polyethylene (PE) waste into valuable products, such as oils, fuels, surfactants, and lubricants. Unfortunately, commercialization has been hampered by inadequate optimization of PE deconstruction due to an inability to either truly characterize the solid reaction products or adjust catalytic conditions to match the ever-evolving product distribution (and associated property changes) during reaction. To address these challenges, a detailed analysis of molecular weight (MW) distributions and thermal characterization was developed and applied to PE deconstruction, which enabled more thorough identification of polymer chains within the solids (e.g., changes in MW or branching structure). Critical distinctions between solids obtained from multiple hydroconversion reactions were captured. For example, solids generated from PE hydrocracking exhibited a broadened MW distribution with a disappearance of a significant fraction of highly-linear segments of the polymer chains. Additionally, the polymer feedstock architecture influenced the interactions with the catalyst and reaction kinetics. By tracking the deconstruction behavior as a function of reaction type, time, temperature, and catalyst design, we mapped critical pathways toward PE valorization. These results will enable the incorporation of changes in intrinsic polymer properties (e.g., MW distributions, branching) into process-specific catalyst, reaction, and reactor-design calculations to enhance the economic potential of PE deconstruction.