A novel thennoset polyurethane (TPU), two amorphous thennoplastics, poly(methyl methacrylate) (PMMA), high impact poly(styrene) (HIPS) and a semi-crystalline polymer, medium density poly(ethylene) (MDPE) were used in the fonnation of a range of polymer/carbon nanotube composites for commercial and development research purposes.· Composites of thennoplastic polymers were produced by melt-processing due to the immediate compliance of the melt-mixing process with current industrial practices and the scarcity of literature pertaining to the subject. In the case ofTPU, multi-walled carbon nanotubes (MWCNTs) were used as the filler material and composites were produced using a specifically designed solution based process. A true nanoscale reinforcing effect was obtained, in that stiffness, strength and relative toughness of the TPU matrix was greatly enhanced on addition of as little as 0.1wt.% MWCNTs. A range of arc discharge MWCNTs, CVD-MWCNTs and f-MWCNTs were used in the fabrication of a range of PMMAlMWCNT composites in order to determine the effect of aspect ratio, physical structure and functionalisation of MWCNTs on the morphology and end 1roperties of the composite material. Carboxyl functionalisation of the MWCNT end-caps promoted homogeneous and anisotropic dispersion and distribution off-MWCNTs within the PMMA matrix, evident from morphological analysis although reducing the intrinsic conductivity of the nanotubes. A lower screw speed than is norinally practised during the twin screw extrusion of nanocomposites achieved the highest degree of nanotube dispersion and distribution in the HIPS studied. Single screw extrusion successfully produced homogeneous MDPE/CVD-MWCNT composites with an electrical percolation threshold of 2wt.% MWCNTs. For all systems, the extent of interfacial interactions between the polymer and MWCNTs was studied using Raman spectroscopy. The formation of a percolated network of MWCNTs in the polymer matrices was also examined in tenns ofrheological and electrical behaviour.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:486255 |
| Date | January 2007 |
| Creators | McClory, Caroline |
| Publisher | Queen's University Belfast |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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