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
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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.
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Keywords
Surface modification of Multi-walled carbon nanotubes , on Properties of Silicone rubber composites
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