Green chemistry approaches to the depolymerisation of polyolefin plastic packaging

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dc.contributor.advisorCollins, Gillian
dc.contributor.authorYap, Forest Tung Jieen
dc.date.accessioned2026-01-21T15:49:50Z
dc.date.available2026-01-21T15:49:50Z
dc.date.issued2025
dc.date.submitted2025
dc.description.abstractThe widespread use of polyolefin plastic packaging has contributed significantly to the global plastic waste crisis, posing severe environmental and economic challenges, making the development of effective plastic degradation strategies imperative for sustainable waste management. This thesis investigates the thermo-oxidative degradation of both virgin (V-) and post-consumer (PC-) low-density polyethylene (LDPE) in acetic acid under relatively mild conditions (120 °C, ambient pressure), evaluating the roles of heterogenous Mn-Fe catalysts, N-Hydroxyphthalimide (NHPI) radical initiator and catalyst-free degradation. Across all experimental conditions PC-LDPE consistently exhibited greater mass loss (~30 %) than V-LDPE (~17 %). Surface-sensitive characterisation by Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy revealed a significantly higher degree of functionalisation for PC-LDPE than V-LDPE, attributed to prior oxidation and additives in post-consumer plastics. Qualitative analysis using HPLC consistently showed the presence of formic acid and succinic acid as major degradation products with additional minor signals also observed in the PC-LDPE. The presence of additives and prior processing history have a strong influence on the degradation pathways of LDPE. We further show that heating in acetic acid alone can drive partial thermo-oxidative conversion of PC-LDPE under mild catalyst-free conditions (120 °C, acetic acid). This approach presents opportunities for designing a mild oxidative pretreatment of PC-LDPE that could be coupled to a subsequent harsher chemical upcycling process.en
dc.description.statusNot peer revieweden
dc.description.versionAccepted Versionen
dc.format.mimetypeapplication/pdfen
dc.identifier.citationYap, F. T. J. 2025. Green chemistry approaches to the depolymerisation of polyolefin plastic packaging. MRes Thesis, University College Cork.
dc.identifier.endpage84
dc.identifier.urihttps://hdl.handle.net/10468/18433
dc.language.isoenen
dc.publisherUniversity College Corken
dc.rights© 2025, Forest Tung Jie Yap.
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/
dc.subjectGreen chemistry
dc.subjectPolyolefin plastic packaging
dc.subjectLow-density polyethylene
dc.subjectPost-consumer LDPE
dc.subjectChemical recycling
dc.subjectThermo-oxidative degradation
dc.titleGreen chemistry approaches to the depolymerisation of polyolefin plastic packaging
dc.typeMasters thesis (Research)en
dc.type.qualificationlevelMastersen
dc.type.qualificationnameMRes - Master of Researchen
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