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A Fundamental Understanding of the Factors Controlling the Chemical Performance of Model Polymer Networks

Knox, Stephen T. (2018) A Fundamental Understanding of the Factors Controlling the Chemical Performance of Model Polymer Networks. PhD thesis, University of Sheffield.

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Abstract

A range of bisphenol based epoxy resin monomers were cured with a range of amines to investigate the influence of nuanced chemical changes of constituent molecules upon the chemical performance of networks. Initially, the curing process was optimised in order to reduce the influence of oxidation and carbamation. Moving away from a stoichiometric formulation was found to result in a slight decrease in chemical performance. Networks cured under an air atmosphere swelled faster, and were more vulnerable to failure. Networks based on DGEBF monomers rather than DGEBA were generally found to exhibit an improved chemical performance. Chain extension of epoxy resin monomers was demonstrated to result in less dense networks which showed lower and slower solvent uptake. Aromatic amines were found to give denser networks which showed reduced and slower sorption (vs. aliphatic analogues). 1,3- substitution of six-membered rings was found to produce networks of a higher performance than 1,4- analogues, irrespective of similar densities. Across the work it was demonstrated that none of the individual physical/thermal properties probed (glass transition temperature, density, crosslink density, beta transition temperature) offered an effective indicator (in isolation) of chemical performance, though a combination of properties indicating a well-packed network gave a good indication of performance. Density was shown to be the most important of these factors.

Item Type: Thesis (PhD)
Academic Units: The University of Sheffield > Faculty of Engineering (Sheffield) > Mechanical Engineering (Sheffield)
Depositing User: Mr Stephen T. Knox
Date Deposited: 04 Feb 2019 09:26
Last Modified: 04 Feb 2019 09:26
URI: http://etheses.whiterose.ac.uk/id/eprint/22715

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