Tracking Chain Populations and Branching Structure during Polyethylene Deconstruction Processes
Date
2024-08-21
Journal Title
Journal ISSN
Volume Title
Publisher
ACS Central Science
Abstract
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 polymer transformations or adjust catalytic conditions to match the ever-evolving product distribution and associated property changes. To address these challenges, a detailed analysis of molar mass distributions and thermal characterization was developed herein and applied to low-density polyethylene (LDPE) deconstruction to enable more thorough identification of polymer chain characteristics within the solids (e.g., changes in molar mass or branching structure). For example, LDPE hydrocracking exhibited comparable rates of polymer chain isomerization and C–C bond scission, and the solids generated possessed a broadened molar mass distribution with a disappearance of a significant fraction of highly linear segments, indicating polymer-structure-dependent interactions with the catalyst. Solids analysis from pyrolysis yielded starkly different results, as the resulting solids were devoid of unreacted polymer chains and had a narrowed molar mass distribution even at short times (e.g., 0.2 h). By tracking the polymeric deconstruction behavior as a function of reaction type, time, and catalyst design, we mapped critical pathways toward PE valorization.
Synopsis
A comprehensive approach to track polymer chain evolution during deconstruction was developed and revealed the influence of deconstruction method and polymer architecture on product distributions.
Description
This article was originally published in ACS Central Science. The version of record is available at: https://doi.org/10.1021/acscentsci.4c00951.
Copyright © 2024 The Authors. Published by American Chemical Society. This publication is licensed under
CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/).
Keywords
catalysts, catalytic reactions, differential scanning calorimetry, polymers, pyrolysis
Citation
Balzer, Alex H., Zachary R. Hinton, Brandon C. Vance, Dionisios G. Vlachos, LaShanda T. J. Korley, and Thomas H. Epps. “Tracking Chain Populations and Branching Structure during Polyethylene Deconstruction Processes.” ACS Central Science 10, no. 9 (September 25, 2024): 1755–64. https://doi.org/10.1021/acscentsci.4c00951.