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CC BY V4.0, Open Access
Thesis
INVESTIGATING THE EFFECTS OF A MECHANICAL AND CHEMICAL RECYCLING METHOD ON THE MATERIAL PROPERTIES OF A VIRGIN BOTTLE-GRADE POLY(ETHYLENE TEREPHTHALATE)
Washington State University
Master of Science (MS), Washington State University
01/2022
DOI:
https://doi.org/10.7273/000004464
Handle:
https://hdl.handle.net/2376/124881
Abstract
Plastic is a material that has provided many benefits to society. Its use spans across many faucets of everyday life, from the electronics we use, to the vehicles that transport us to the packaging used to protect our food. The beginnings of its mass manufacture started without due consideration to the end-of-life plan for the material. Now, an excess volume of plastic waste exists, and the consequences have yet to be fully understood. Recycling has been introduced as a method to manage the plastic waste and has been developed into four main categories. Of these four, only mechanical recycling and chemical recycling have been designed to process this post-consumer waste into a feedstock for reuse, but their use are not without limitation. Mechanical recycling melt processes plastic by extrusion and returns the material directly to a pellet form, but the risk of degradation to the material is high. Chemical recycling depolymerizes a plastic into monomers and oligomers by the use of solvents, but requires either high energy loads or complex catalysts. This research investigates both recycling methods on a common recycled plastic, bottle-grade poly(ethylene terephthalate) (PET), to study their impacts on material property. First, the extent of degradation to the bottle-grade PET was studied over four iterations of melt processing by extrusion at 260°C. After each iteration, a decrease in the molecular weight of the plastic was measured, impacting the crystallinity, rheological and mechanical properties. Second, a bottle-grade PET was reacted in an extruder-like reactor with ethylene glycol and zinc acetate dihydrate to study depolymerization over two reaction temperatures and three reaction times. Within 8 minutes, at temperatures of 255°C and 185°C, 98% of the bottle-grade PET was depolymerized to low molecular weight oligomers. This corresponded to a decrease in melt temperature from 242°C to 162°C.
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Details
- Title
- INVESTIGATING THE EFFECTS OF A MECHANICAL AND CHEMICAL RECYCLING METHOD ON THE MATERIAL PROPERTIES OF A VIRGIN BOTTLE-GRADE POLY(ETHYLENE TEREPHTHALATE)
- Creators
- Jonathan Patrick Hatt
- Contributors
- Karl Englund (Advisor)Vikram Yadama (Committee Member)Jinwen Zhang (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Voiland College of Engineering and Architecture
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Number of pages
- 120
- Identifiers
- 99900881631501842
- Language
- English
- Resource Type
- Thesis