The Effect Of Surface Modification Of Multi-Walled Carbon Nanotubes On Properties Of Silicone Rubber Composites
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Date
2010-05
Authors
Chua, Tze Ping
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
In the present study, silicone rubber type poly(dimethylsiloxane) (PDMS)
was chosen as a matrix for Thermal Interface Materials (TIM) due to its ease of
processing, inert to chemical attack, non-toxic and high thermal stability. Two types
of modified multi-walled carbon nanotubes (MWNTs), which are diphenylcarbinol
modified MWNTs (D-MWNTs) and silanized diphenylcarbinol modified MWNTs
(SD-MWNTs) were produced by chemically treatment. D-MWNTs were prepared
by one electron reduction of benzophenone by potassium metal and SD-MWNTs
were prepared by treated D-WMNTs with 3-aminopropyltriethoxysilane (3APTES).
Raman and UV-vis spectroscopies reveal the presence of covalent sidewall
functionalization for sample D-MWNTs. Fourier transform infrared spectroscopy
(FTIR) and energy dispersion spectroscopy (EDS) analysis confirmed the presence
of diphenyl-carbinol and silane on the surface of the D-MWNTs and SD-MWNTs.
Transmission electron microscopy (TEM) indicates that the side wall of the DMWNTs
and SD-MWNTs are covered by non-uniform layer. Studies on the
application of modified MWNTs; D-MWNTs and SD-MWNTs in PDMS matrix
show that the grafting of silane molecules onto D-MWNTs improves the dispersion
of MWNTs in PDMS matrix; this subsequently enhances the thermal, mechanical
and dynamic mechanical properties as compared to composites containing UMWNTs.
In general, with the application of 1.5 vol.% SD-MWNTs in PDMS
matrix, thermal conductivity increase 123% and 41% compared to neat PDMS and
1.5 vol.% U-MWNT/PDMS composites, respectively. In short, improvement in
thermal stability, storage modulus and tensile strength of modified MWNTs in
PDMS matrix are due to an increase interaction between the fillers and the matrix.
Description
Keywords
Surface modification of Multi-walled carbon nanotubes , on Properties of Silicone rubber composites