THESIS
2008
xxvii, 191 leaves : ill. (some col.) ; 30 cm
Abstract
Fullerenes and carbon nanotubes are the most important and promising nanomaterials to date.
60 70...[
Read more ]
Fullerenes and carbon nanotubes are the most important and promising nanomaterials to date.
In order to obtain purified C
60 and C
70 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.
Post a Comment