Masters Theses
Date of Award
12-2024
Degree Type
Thesis
Degree Name
Master of Science
Major
Chemistry
Major Professor
Brian K. Long
Committee Members
Mike Kilbey, Johnathan N. Brantley
Abstract
Plastic waste, particularly from polyolefins like polyethylene (PE) and polypropylene (PP), presents significant environmental and recycling challenges due to their chemical stability and resistance to degradation. Current recycling methods often fail to deliver high-value outputs, with chemical recycling hindered by inefficiencies in catalyst performance and a limited understanding of polymer-catalyst interactions. This thesis addresses these challenges by proposing a hypothesis that by tailoring catalyst surface properties and optimizing solvent interactions, it is possible to design a system that selectively adsorbs larger polymer molecules for catalytic breakdown while facilitating the desorption of smaller, processed molecules. To test this hypothesis, end-functionalized polyethylene models of controlled molecular weights were synthesized using ring-opening metathesis polymerization (ROMP) with Grubbs 2nd generation catalyst. Chain transfer agents (CTAs) were employed to introduce distinct terminal functionalities, creating a library of polyethylene models for systematic analysis. These models were evaluated for their adsorption behavior and catalytic degradation efficiency over catalyst surfaces under controlled conditions. High-temperature size exclusion chromatography (HT-SEC) was used to analyze the molecular weights of depolymerized products, while catalytic performance metrics correlated with the polymers' molecular weight and molecular weight distribution. By addressing the knowledge gaps in polymer-catalyst interactions, this research will contribute to developing more efficient and sustainable recycling technologies for polyolefins, advancing the transition to a circular economy for plastic waste.
Recommended Citation
Patter, Rakesh, "Conversion of plastic waste into poly crude. " Master's Thesis, University of Tennessee, 2024.
https://trace.tennessee.edu/utk_gradthes/12861