Dispersion stability of the aminosilane-grafted mesoporous carbons in different solvents

Abstract

In this study, 3-aminopropyltriethoxysilane (APTES) was grafted on the surface of oxidized mesoporous carbon of cubic structure. The process of modification was carried out at 40 °C for 8 h with increasing amount of aminosilane (1.2, 3, 6 mL). The new hybrid materials were characterized by FT-IR spectroscopy, low temperature nitrogen sorption, scanning electron microscopy, elemental analysis, thermogravimetric methods, Boehm titration, laser diffraction, dynamic and multiple light scattering. Functionalization of carbon with aminosilane significantly affected its structural, textural and surface properties. The chemical interaction of aminosilane with the oxidized carbon material was confirmed by FT-IR spectra. Thermogravimetric analysis of the functionalized mesoporous carbons exhibited three peaks at temperatures in the range 60–650 °C that correspond to the degradation of chemically grafted aminosilane on the materials surface. Multiple light scattering was applied to assess the stability of the materials in water, toluene and Tween 80 non-ionic surfactant solutions. In polar solvent all aminosilane-grafted mesoporous carbons were more stable than the unmodified material. In toluene and surfactant solution the sample modified with the lowest amount of APTES showed the highest stability. Additionally, it was proved that the more acidic groups were on the surface of mesoporous carbons the more stable was the dispersion in surfactant solution.