Effect of modification of carbon nanotubes by 3-aminopropyltriethoxysilane on the properties of silicone nanocomposites

The modification of the silicone compound with carbon nanotubes (CNTs) resulted in composites with improved physical properties and thermal stability. The carbon nanotubes were functionalized with 3-aminopropyltriethoxysilane for a more uniform distribution in the matrix. Initial and pre-oxidized CNTs containing different amounts of carboxyl groups were subjected to silanization. From 0.5 to 3 wt. % of the initial or functionalized CNTs were injected into Silagerm 2111 silicone compound. The obtained samples were characterized by FTIR and Raman spectroscopy and TG/DSC analysis. The silicon content in the silanized CNTs was determined by X-ray fluorescence spectroscopy. It was shown that the pre-oxidation of CNTs slightly affects the silicon content in the silanized nanotubes, which is up to (7.69 ± 0.92) wt. %. According to Raman mapping of the surface of silicone composites, the silanized CNTs are more uniformly distributed in the surface layer of the material than the original nanotubes. This effect has a positive effect on the physical-mechanical properties of the composites. CNTs functionalized by 3-aminopropyltriethoxysilane are 1.5 times more effective in increasing the electrical conductivity than the original CNTs. The resulting composites retain their mechanical characteristics after thermal exposure and can be operated over a wider temperature range than the original silicone compound.