The aim of this study was to explore the effects of a range of variables on the properties of ionomers, and also to investigate the structure-morphology-property relationships in these materials in order to advance our understanding in the light of the EHM model. In the first part of the work, the influence of variables such as sample preparation conditions, molecular weight and degree of neutralization on the dynamic mechanical properties of ionomers were studied. / In the second part, the effects of surfactant addition and chemical structure of ionomers were investigated. Sodium sulfonated polystyrene ionomers were mixed with the surfactant sodium p-dodecylbenzene sulfonate. This surfactant molecule has a head group identical to the ionic group of the polymer chain. Therefore, the head group resides in the multiplets, and tail group in the restricted mobility region surrounding the multiples. This results in a dramatic decrease in the cluster $T sb{ rm g}$ as a function of the amount of added surfactant. In the next project, the contact surface area of the chain and its effect on multiplet size was studied. An inverse relationship between contact surface area and size of multiplet was found; if the size of multiplet is decreased, the cluster $T sb{ rm g}$ increases and the ionic plateau is also higher and longer. Furthermore, when the pendant group of the polymer is replaced by a bulkier group, the chain becomes stiffer. As a result, the two $T sb{ rm g}$s shift to higher temperatures. In still another part of the study, the dynamic mechanical properties of poly(styrene-co-sodium methacrylate) ionomers were re-investigated in detail. Discontinuities in the plots of various parameters obtained from the tan $ delta$ vs temperature and modulus vs temperature curves as a function of the ion contents were found. These discontinuities suggest that there are two morphological changes in the system as a function of the ion contents, one at ca. 4-6 and the other at ca. 12-14 mol % of ions. In addition, the data were interpreted using filler and percolation concepts. The Guth equation for modulus vs filler content is applicable up to 30 volume % of the clusters. The Halpin-Tsai equation for the regular system is also applicable at low ion contents. For the percolation approach, the percolation threshold was found at 5.4 mol % of ions. The critical exponent and critical volume fraction of clusters were found to be 1.31 and 0.64, respe
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.28475 |
| Date | January 1994 |
| Creators | Kim, Joon-Seop |
| Contributors | Eisenberg, Adi (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Chemistry.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001425295, proquestno: NN00105, Theses scanned by UMI/ProQuest. |
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