title: Silylation of montmorillonite surfaces: dependence on solvent nature.
abstract: Silylation of clay mineral surfaces has attracted much attention due to their extensive applications in materials science and environmental engineering. Silylation of montmorillonite surfaces with 3-aminopropyltriethoxysilane was carried out in polar-protic and nonpolar solvents. The swelling property of the silylated montmorillonites was investigated by intercalating with cetyltrimethylammonium bromide. Silylated montmorillonites prepared in nonpolar solvents showed a larger amount of loaded silane and a higher extent of condensation among different silane molecules, comparing with those prepared in polar-protic solvents with high dielectric constant. Meanwhile, the silylated montmorillonites prepared in nonpolar solvents displayed poor swelling property due to the linkage between silane oligomers and clay layers, that is, the neighboring clay layers were locked by the silane oligomers. The present study demonstrated that the polarity of the solvents used had an important influence on the extent of grafting, interlayer structure, and swelling property of the silylated products. This is of high importance for synthesis and application of silylated clay minerals.
authors.affiliation: Key Laboratory of Mineralogy and Metallogeny, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, PR China.
authors.forename: Linna
authors.initials: L
authors.lastname: Su
authors.forename: Qi
authors.initials: Q
authors.lastname: Tao
authors.forename: Hongping
authors.initials: H
authors.lastname: He
authors.forename: Jianxi
authors.initials: J
authors.lastname: Zhu
authors.forename: Peng
authors.initials: P
authors.lastname: Yuan
authors.forename: Runliang
authors.initials: R
authors.lastname: Zhu
mesh_terms: D000538:Aluminum Silicates; D001546:Bentonite / Q000737:chemistry*; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry; D000077215:Clay; D011437:Propylamines; D012821:Silanes / Q000737:chemistry*; D012997:Solvents; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: D000538:Aluminum Silicates; D002593:Cetrimonium Compounds; D011437:Propylamines; D012821:Silanes; D012997:Solvents; D001546:Bentonite; C477625:amino-propyl-triethoxysilane; D000077215:Clay; D000077286:Cetrimonium