Date of Award
12-2025
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Packaging Science
Committee Chair/Advisor
Dr. James Sternberg
Committee Member
Dr. Kay Cooksey
Committee Member
Dr. Duncan Darby
Abstract
Aminolysis is a chemical depolymerization technique used in deconstructing polyethylene terephthalate (PET) polymer chains into their monomeric units, which can then be used to synthesize second-generation polymers. Commonly used chemical depolymerization methods, such as hydrolysis and methanolysis, involve harsh reaction conditions, such as high pressure and high temperature, to isolate monomers that can create second-generation PET resins. Even though these methods aid in synthesizing novel polymers, the resulting polymers tend to have a very short lifespan and similar value to PET. The approach followed in this study uses aminolysis as an ambient pressure technique to develop precursors to synthesize high-value polymers with prolonged lifespans and properties to address current plastic waste concerns. Semi-aromatic polyamides (SAP) are synthesized from chemically recycled PET due to their high melting point and heat resistance, combined with good melt processability, providing improved properties in contrast to PET. In the current study, four novel types of SAPs were synthesized using terephthalamide precursors recovered from the aminolysed post-consumer PET using biobased diamines and dicarboxylic acids. Even though aminolysis techniques have been used in previous studies, this work explored biobased components from castor oil: decamethylene diamine (DMD) during chemical recycling and sebacic acid (SA) during polymerization. Structure-wise, the resulting SAPs were similar to polyphthalamides (PPA) with novel structures given the aromatic portion from terephthalic acid (TPA) and an aliphatic portion from the diamines and diacids. The synthesized material exhibited excellent thermal stability with high glass transition temperatures (Tg) and melting points (Tm). The created novel polymers were studied for their properties with varying structures given by the different aliphatic chain lengths to understand the fundamental parameters needed to produce a valuable polymer from post-consumer PET.
Recommended Citation
Podduwala Hewage, Sathiska Kaumadi, "Biobased Chemical Recycling: Aminolysis of Pet Using Renewable Reagents and Monomers to Synthesize New Semi-Aromatic Polyamides" (2025). All Theses. 4623.
https://open.clemson.edu/all_theses/4623
Author ORCID Identifier
https://orcid.org/0009-0009-7033-0607