Abstract
Large pore MCM-41 silica with the pore diameter of 5.0 nm was chemically modified by bonding monomeric-type ligands, such as trimethylsilyl, butyldimethylsilyl, and octyldimethylsilyl, as well as polymeric-type 3-aminopropylsilyl, (hexanoyl-3-aminopropyl)silyl, and octylsilyl ligands. The obtained materials were characterized using elemental analysis, high-resolution thermogravimetry (TGA), and nitrogen adsorption at 77 K in a wide range of pressures. Surface coverages of bonded ligands were between 2.5 and 3.0 μmol/m2. It was shown that pore diameters of the samples studied decreased systematically with the increase in size of ligands. The modified materials exhibited narrow and monodisperse pore size distributions, indicating that the chemical bonding procedure did not diminish the structural ordering of the MCM-41 support. TGA data showed that the surface affinity to water was strongly dependent on the structure and functionality of the bonded species. Nitrogen adsorption data provided additional infor...
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