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Synthesis, purification and applications of carbon nanomaterials and their polymer nanocomposites

Authors Wang, Huan
Issue Date 2008
Summary Fullerenes and carbon nanotubes are the most important and promising nanomaterials to date. In order to obtain purified C60 and C70 from the soot of mixed fullerenes, an ordered mesoporous carbon, CMK-3, was synthesized, characterized and used as adsorbent. It was found that the adsorption capacity of CMK-3 was four times higher than that of activated carbon (AC). The reversibility of fullerene adsorption on CMK-3 was also studied. In addition, another carbon nanomaterial with a specific nanostructure, aligned multi-walled carbon nanotubes (MWCNTs), were grown on both sides of a metallic or metal-coated substrate by water vapor-assisted chemical vapor deposition (CVD). By manipulating various operating factors, the morphology and thickness of these carbon nanotube films could be adjusted. This technique was used to fabricate a thermal interface material, made up of a thin copper foil covered with Cr-Au-MWCNT on both sides. The Hot Disk® method was applied to measure the thermal conductivity of these CNT-TIMs. Results showed that a thicker copper foil substrate or CNT layer led to a lower overall thermal resistance. The laser flash method was used to study the performance of the bilayer aligned CNT-TIMs using two copper plates as heat source and sink. An enhancement in thermal conductivity of more than 290% could be obtained under an applied contact pressure of 0.01 MPa, as compared with two copper plates in direct contact. Meanwhile, the tribological properties of aligned CNT/fullerene-epoxy nanocomposites were also studied by nanoscratch, nanowear, and nano-indentation tests. Compared with neat epoxy, aligned CNT and fullerene-epoxy nanocomposites showed lower friction coefficient in scratch tests, a reduction of 38.1% and 26.2%, respectively. Finally, a method for fast forming of polymer/dispersed MWCNT nanocomposite hollow cylinders with microwave irradiation of polymer/MWCNT nanocomposite particles with a core-shell structure was achieved. The impact of irradiation time and concentration of MWCNTs on the morphology, geometrical characteristics, microhardness and electrical resistivity was evaluated.
Note Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2008
Language English
Format Thesis
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