Synthesis and Characterisation of Organo Phyllosilicates Containing Both Si, Al, and Mg
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2002 MRS Spring Meeting Symposium Q: HYBRID ORGANIC/INORGANIC MATERIALS SYNTHESIS AND CHARACTERISATION OF ORGANO PHYLLOSILICATES CONTAINING BOTH Si, Al, AND Mg Maguy JABER (a), Jocelyne MIEHE-BRENDLE(a), Ronan LE DRED (a) [email protected], [email protected], [email protected] (a)
Laboratoire de Matériaux Minéraux, UMR 7016, Ecole Nationale Supérieure de Chimie de Mulhouse, Université de Haute Alsace. 3, rue Alfred Werner, 68093 Mulhouse Cedex (France). Abstract Hybrid materials like organo-phyllosilicates exhibit new properties which make them potential candidates for many industrials applications as rubber reinforcement, environmental barriers…. With this aim, a series of new layered inorganic-organic solids, with organic functionalities directly bonded to the inorganic sheets via the Si- C bond, were prepared by a template sol-gel synthesis under soft conditions (room temperature) using octyltriethoxysilane as the silica source, aluminum acetylacetonate as the alumina source, magnesium nitrate and sodium hydroxide. These hybrid materials belong to the 2:1 trioctahedral phyllosilicates family with inorganic compositions close to saponite. The ratio of Al (x) could be varied between 0 and 0.33. The x-ray diffraction patterns agree with a layers structure (presence of the (00l) peak series and the (060) peak). The high d001 spacing values (2.4-2.6 nm) can be related to the octyl chains present in the interlayer space. DRIFT and 13 C NMR spectra indicate that the Si- C bonds are intact and siloxanes are fully hydrolyzed giving SiOAl and SiOMg bonds. 27 Al and 29 Si NMR were carried out in order to determine the repartition of the different elements in the layer: Al substitutes for Si in the tetrahedral layer and for Mg in the octahedral one. These results were determined by elemental analysis. The DTA-TG results show that the organic matter start to decompose in air above 250°C but its complete removal needs temperatures higher then 800°C. The aspect of the materials depends on the value of x; it varies from greasy, waxy, waxy powdery and finally powdery. The hydrophilicity of the solids depends strongly on the aluminum content. Introduction In recent years there was a growing interest in the development of hybrid materials containing both organic and inorganic components due to the wide range of applications. The main method to obtain these kinds of solids is the sol- gel method. This method provides a useful low-temperature route for generating in situ a metal oxide phase from an alkoxide precursor, through hydrolysis and condensation reactions. Up to now, the synthesis of a considerable number of hybrids materials having a talc- like or pyrophyllite- like structure have been mentioned[1-6]. As previously stated[2], a probable mechanism for the formation of these selforganized structures should be similar to that involved in the formation of mesoporous silicas, aluminosilicate molecular sieves, and also inorganic-organic nanocomposites by using different surfactants as templates. During the sol-gel template synthesis, t
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