The adhesion and subsequent failure of a commercially available photocured resin applied to various ceramic substrates, used for electronics applications, has been investigated. The adhesive system was studied under both ambient and hostile, (water immersion at 50°C) conditions. The environmental stability of the system was investigated using two different mechanical tests, (simple butt-joints and a modified Boeing wedge test). In each case, the precise locus of failure was determined by a combination of surface analytical (XPS and ToF-SIMS) and microscopy techniques, (SEM). On the basis of these results, adhesion and failure mechanisms are proposed for the system. The presence of defects within the adhesive was found to initiate failure under ambient, (dry) conditions. Prolonged immersion in water, (for at least 2 weeks), was found to result in near-interfacial failure with a thin, (of the order of nanometres), overlayer of polymer remaining on the surface of the adherend. Subtle differences between this polymer overlayer and the bulk resin were observed. A model is proposed in which one of the minor resin components aggregates at the inorganic surface, creating a localised region which is extremely hydrophillic in nature. This makes the system particularly vulnerable to attack by water. In order to test this model, a reformulated batch of resin underwent the same environmental tests. The modified resin displayed a modest improvement in its ability to withstand hostile conditions, (prolonged immersion in water at 50°C) and the polymer residue remaining on the inorganic substrate was identical to that of the bulk polymer. This project has provided a unique opportunity to study the adhesion of a specific class of adhesives to bulk ceramic oxides, rather than to oxides of metals. One of the major benefits of which, was therefore the absence of any effects due to corrosion of the substrate. The project was also unusual in that it effectively went "full-circle", with the resin undergoing reformulation on the basis of the results obtained from the standard resin. The reformulated product was found to have superior wet adhesion, but poor mechanical properties.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:259527 |
| Date | January 1994 |
| Creators | Taylor, Alison M. |
| Publisher | University of Surrey |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://epubs.surrey.ac.uk/844533/ |
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