The functionalization of spherically shaped carbon-based nanomaterials
Date
2009-09-11T11:41:16Z
Authors
Tetana, Zikhona Nobuntu
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Abstract
In this dissertation, the synthesis and characterization of side-chain fullerene-containing
polymers has been accomplished and reported (chapter 3). This was achieved by first
synthesizing a C60-cyclohexadiene cycloadduct, followed by its polymerization with
norbornene via a ring opening metathesis polymerization (ROMP) procedure using the
Grubbs’ second generation catalyst. For comparison purposes, 1,4,5,6,7,7-hexachloro-5-
norbornene-endo-2,3-heptylimide monomer was also copolymerized with C60-
cyclohexadiene cycloadduct. The novel materials were characterized using FT-IR, UVVIS,
NMR spectroscopic techniques as well as TGA and DSC analyses. The complex
1,4,5,6,7,7-hexachloro-5-norbornene-endo-2,3-heptylimide was also characterized by
single crystal X-ray diffraction. The resulting copolymers revealed that the main
fullerene features were retained in the polymers
In the second part of this dissertation, carbon spheres (CSs) with high purity were
synthesized by the CVD method using acetylene as a carbon source (chapter 4). The CSs
were characterized using Raman spectroscopy, TGA and TEM and data revealed their
graphitic and crystalline nature. Successful functionalization of CSs with cyclopentadiene
(CS-C5H6) and cyclohexadiene (CS-C6H8) was achieved by way of a Diels-Alder type
cycloadditon. The functionalized CSs showed good solubility in organic solvents such as
chloroform, dichloromethane and DMF. Boron-doped carbon spheres were also
synthesized and characterized, with special attention placed on the diameters of carbon
spheres obtained in the presence of the boron source. Characterization of the CSs
synthesized was performed by means of Raman spectroscopy, TEM, and laser ablation
mass spectrometry analysis. The average diameter and shell thickness of the carbon
spheres are greatly influenced by the boron incorporation into the CSs, resulting in CSs with a larger diameter.