Effects of surface-functionalized multi-walled carbon nanotubes on the properties of poly(dimethyl siloxane) nanocomposites

The effects of surface-functionalized multi-walled carbon nanotubes (MWNTs) on the properties of poly(dimethyl siloxane) (PDMS) nanocomposites are investigated in the present study. The surface functionalization of MWNTs is carried out by diphenyl-carbinol functionalization followed by reaction with multifunctional silane, 3-aminopropyltriethoxisilane. Fourier transform infrared spectroscopy (FT-IR) and energy dispersion spectroscopy (EDS) analysis are used to confirm the presence of diphenyl-carbinol and silane on the surface of the MWNTs. The effects of the MWNTs’ surface treatment on the thermal and electrical properties of poly(dimethyl siloxane)-based (PDMS) nanocomposites are also studied. The results show that the grafting of silane molecules onto diphenyl-carbinol-functionalized MWNTs (SD-MWNTs) improves the dispersion of MWNTs in PDMS; this subsequently enhances the thermal conductivity and dynamic mechanical properties as compared to those containing unmodified (U-MWNTs) and diphenyl-carbinol-functionalized MWNTs (D-MWNTs). The electrical conductivity of the nanocomposites is shown to decrease due to the wrapping of MWNTs with non-electrical-conducting organic materials.