The discovery of nanotubes with unique mechanical, electrical, and
thermal properties has led to their use in the development of the next generation
of composite materials. However, their poor solubility and dispersion properties
in any organic and aqueous solvents limits their potential applications.
In order to improve their solubility, single-walled carbon nanotubes
(SWNTs) were functionalized along their sidewalls with phenol groups using a
1,3-di^polar cycloaddition reaction. These phenols could be further derivatized
with 2-bromoisobutyryl bromide, resulting in the attachment of atom transfer
radical polymerization initiators to the sidewalls of the nanotubes. These
initiators were found to be active in the polymerization of methyl methacrylate
and t-butyl acrylate from the surface of the nanotubes. However, the
polymerizations were not controlled, leading to the production of high molecular
weight polymeric grafts with relatively large polydispersities. The resulting
polymer carrying nanotubes were analyzed by IR, Raman spectroscopy, solid-state NMR, DSC, TEM, and AFM. The nanotubes functionalized with
poly(methyl methacrylate) were found to be insoluble in organic solvents, such as
THF and CH2CI2. However, the dispersion property of SWNTs in the polymer matrix
was improved dramatically.
Another monomer t-butyl acrylate (t-BuA) was also polymerized using
the same macroinitiators. It was found that the SWNTs functionalized with t-BuA
iii were soluble in a variety of organic solvents. The t-butyl groups of these
appended polymers could also be removed to produce nanotubes functionalized
with poly (acrylic acid), resulting in nanocomposites that are soluble in aqueous
solutions.
In addition, polystyrene (PS) which was prepared by stable free radical
polymerization, was used to functionalize SWNTs through the radical coupling
reaction. IR, NMR, TEM, and AFM confirmed that this polystyrene was
covalently bonded to the SWNTs. It was also found that the resulting PS-SWNTs
composites were quite soluble in organic solvents, such as THF and CH2C12. / Thesis / Master of Science (MSc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/25236 |
| Date | 09 1900 |
| Creators | Yao, Zhaoling |
| Contributors | Adronov, Alex, Chemistry |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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