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Title: The morphology and toughness of thermoplastic-modified epoxy polymer with carbon nanotubes or silica nanoparticles
Author: Brooker, Dorothy
ISNI:       0000 0004 2674 3339
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2009
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The research carried out in this thesis was to investigate the effects of incorporating nanomodifiers into amine cured epoxy resin, with a second phase of thermoplastic. The morphology and properties of the epoxy with various percentages of thermoplastic with reactive endgroups were assessed. As the percentage of thermoplastic was increased the morphology changed from spherical particulate, to co-continuous and finally phase inverted. The Young’s modulus and 0.2% proof stress of the material were unaffected by the addition of the thermoplastic. The ultimate tensile strength (UTS) and fracture properties increased with increasing thermoplastic content. Several methods of dispersion for the nanotubes were tested using different types of multiwalled carbon nanotubes. Sonicating non-functionalised Thomas Swan nanotubes into the epoxy gave the best dispersion. The dispersions were assessed using a greyscale analysis, and a quadrat analysis of transmission electron micrograph collages. Both methods gave comparable results. The addition of nanotubes to the blend was found to have no effect on the tensile or fracture properties of the polymer. The addition of nanosilica to the blends was found to give an increase in Young’s modulus but had no effect on the UTS, 0.2% proof stress or fracture properties. Plane strain compression tests were used to investigate why this epoxy was not toughened by the addition of nanosilica. These revealed that an epoxy which will toughen with the addition of nanosilica shows strain softening and significant shear band formation while the epoxy used throughout this thesis does not. Finally the thermoplastic was used with different endgroups. Changing the endgroup from one reactive group to another had no effect on morphology, but resulted in a slight decrease in fracture properties. The unreactive endgroup had a significant effect on the morphology and resulted in general in an increase in fracture properties and a decrease in UTS.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available