Show simple item record

dc.contributor.authorDawidziuk, Karolinaen
dc.description.abstractThis thesis investigates the fundamentals of modification of polylactic acid (PLA) and poly(3-hydroxyalkanoates) (PHAs), focusing on improving the understanding of the reactivity of these polymers in the presence of peroxide and multifunctional coagents. The first objective was to examine the effects these modifications had on PLA and to compare them to a well understood polyolefin system, ethylene octene copolymer (EOC). The linear viscoelastic (LVE) properties and molecular weight distributions showed that in the presence of peroxide and coagent these systems were able to produce long-chain branched structures, with allylic coagents being more effective at altering the chain architecture. These reactions were found to proceed through a radical mechanism as oppose to other forms of ionic chemistry. Evaluation of the abstraction efficiencies (AE) and graft propagation of monofunctional coagents showed that PLA is a poor hydrogen donor and the effectiveness of the allylic coagents is likely a result of solubility between the polymer and coagent in the melt. The second objective was to investigate the chemical modification of poly(3-hydroxyalkanoates) (PHAs), with different lengths of side chains. Medium-chain-length PHAs (MCL-PHAs) showed an affinity for both allylic and acrylic coagents with increases in viscosity, the appearance of shear thinning, and bimodal molecular weight distributions. On the other hand, the short-chain-length PHAs (SCL-PHAs), poly(3-hydroxybutyrate) PHB, preformed very similar to what was observed with PLA, where allylic coagents out preformed the acrylate coagents. The AE of these materials gave significant insight into the reactivity. As the alkane side chain length was increased from SCL-PHAs to MCL-PHAs, the number of methylene group increased and as a result more hydrogen abstraction sites became available, thus resulting in higher AE. This implies there is a greater probability for coagents to graft onto the polymer backbone and therefore the promotion of branched structures.en
dc.relation.ispartofseriesCanadian thesesen
dc.rightsCC0 1.0 Universalen
dc.rightsQueen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canadaen
dc.rightsProQuest PhD and Master's Theses International Dissemination Agreementen
dc.rightsIntellectual Property Guidelines at Queen's Universityen
dc.rightsCopying and Preserving Your Thesisen
dc.rightsThis publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.en
dc.subjectReactive modificationen
dc.subjectPolylactic acid (PLA)en
dc.subjectPoly(3-hydroxyalkanoates) (PHAs)en
dc.titlePeroxide-initiated Modification of Polylactic acid (PLA) and Poly(3-hydroxyalkanoates) (PHAs) in the Presence of Allylic and Acrylic Coagentsen
dc.contributor.supervisorKontopoulou, Mariannaen
dc.contributor.supervisorParent, J Scotten
dc.contributor.departmentChemical Engineeringen's University at Kingstonen

Files in this item


This item appears in the following Collection(s)

Show simple item record

CC0 1.0 Universal
Except where otherwise noted, this item's license is described as CC0 1.0 Universal