The effect of various types of post-synthetic modifications on the structure and properties of MCM-41 mesoporous silica

Abstract MCM-41 mesoporous silicas synthesized by hydrothermal method were subsequently modified by 3-aminopropyltrimetoxysilane (APTMS) and trimethylchlorosilane (TMCS) via two different grafting methods, i.e. attaching functional groups with or without solvent. The post-synthetic modification, grafting, was applied due to its flexibility for the introduction of functional moieties into the favorite locations of the particles. The primary purpose of this study was to evaluate the effects of grafting methods as well as organosilanes on the modified MCM-41 particles. To achieve this aim, the obtained materials were investigated by various techniques including Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), N 2 adsorption–desorption, transmission electron microscope (TEM), dynamic light scattering (DLS) and thermogravimetric analysis (TGA) to examine the functional groups, crystallinity, surface area, morphology, particle size distribution and amounts of functional groups, respectively. The results confirmed that the spherical MCM-41 particles were successfully functionalized by APTMS and TMCS. Moreover, the surface area and average pore diameters of the particles were affected by the inherent properties of organosilanes such as their side chains and catalytic behaviors. In addition to the type of organosilanes, the grafting methods due to the various interactions between different components such as the surfactant, organosilane and acid had a tremendous impact on the modification process.