Thermo-mechanical and curing behaviour of epoxy/dicarboxylic acid vitrimers

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dc.contributor.advisorSkordos, Alexandros A.
dc.contributor.advisorAyre, David
dc.contributor.advisorThakur, Vijay Kumar
dc.contributor.authorShen, Shouqi
dc.date.accessioned2025-06-24T12:35:22Z
dc.date.available2025-06-24T12:35:22Z
dc.date.freetoread2025-06-24
dc.date.issued2023-09
dc.descriptionAyre, David - Associate Supervisor Thakur, Vijay Kumar - Associate Supervisor
dc.description.abstractThis research delineates the complex relationships between the chemical evolution processes and the physical behaviour of vitrimeric materials, particularly focusing on the transesterification bond exchange mechanism. The curing behaviour, stress relaxation, and high-temperature viscoelastic behaviour of dicarboxylic acid -bisphenol A diglycidyl ether vitrimers are investigated, with respect to the influence of catalysts content and dicarboxylic acid chain length. The influence of catalyst concentration and dicarboxylic acid chain length on the glass transition temperature and bond exchange rate is significant. A notable finding is the substantial decrease in both activation energy from 120 to 74 𝑘𝐽/mol and glass transition temperature from 36°C to 6°C as the carbon chain length increases from 6 to 14 carbons, due to enhanced monomer flexibility. The catalyst and dicarboxylic acid structure play a crucial role in polymerisation, significantly affecting the cure kinetics of the process and, consequently, material stability and processing. The cure kinetics of epoxy-dicarboxylic acid systems are described using a diffusion limitation modified autocatalytic model, showcasing an average 84% goodness of fit, highlighting its effectiveness in understanding these systems. The study investigates temperature-dependent thermo- mechanical properties and thermal degradation, revealing that the speed of formation and extent of crosslinks are influenced by temperature, which in turn affects thermomechanical properties, and also shows that mechanical properties increase at higher temperature, along with enhanced thermal stability as the length of the dicarboxylic acids increases. This study provides a robust foundation for future research endeavours, aiming to optimise vitrimer properties for diverse and efficient applications including advanced composites in aerospace and automotive sectors, self-healing materials, eco-friendly recyclable thermosets, and adaptable biomedical devices.
dc.description.coursenamePhD in Manufacturing
dc.identifier.urihttps://dspace.lib.cranfield.ac.uk/handle/1826/24077
dc.language.isoen
dc.publisherCranfield University
dc.publisher.departmentSATM
dc.rights© Cranfield University, 2023. All rights reserved. No part of this publication may be reproduced without the written permission of the copyright holder.
dc.subjectVitrimer
dc.subjectEpoxy
dc.subjectDicarboxylic acid
dc.subjectCuring
dc.subjectKinetics Modelling
dc.subjectTransesterification
dc.subjectStress Relaxation
dc.subjectThermal Degradation
dc.subjectRheology
dc.subjectDifferential Scanning Calorimetry (DSC)
dc.titleThermo-mechanical and curing behaviour of epoxy/dicarboxylic acid vitrimers
dc.typeThesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnamePhD

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