Properties of the Surface of Silicas Modified with Bi- and Trifunctional Perfluorohexylsilanes: Adsorption of Benzeneстатья
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Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Аннотация:Diffuse reflection IR spectroscopy, static adsorption, and gas chromatography were used to study the chemistry and adsorption properties of the surface of silicas modified by chemically grafted bi- (C6F13(II)) and trifunctional (C6F13(III)) perfluorohexylsilanes. It was established that the modification of silica (SiO2)results in a nearly complete screening of free silanols. At the same time, IR spectra featured absorption bands belonging to weakly perturbed OH groups capable of interacting with benzene molecules. The IR spectroscopy
data on benzene adsorption were found to be in close agreement with the results of static adsorption and chromatographic measurements, according to which the specific amount of benzene adsorbed decreases in the series SiO2>C6F13(III)>C6F13(II). It was demonstrated that the heat of adsorption of benzene on the C6F13(III) sample is higher than that on the initial carrier. Grafted layers prepared from the trifunctional modifier exhibited
higher efficiency in preventing benzene molecules from reaching the carrier surface.