Sol–gel preparation of aminopropyl-silica-magnesia hybrid materials |
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Authors: | Rodrigo Brambilla Joel Poisson Cláudio Radtke Marcia S L Miranda Mateus B Cardoso Ian S Butler João Henrique Z dos Santos |
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Institution: | 1.Instituto de Química,UFRGS,Porto Alegre,Brazil;2.Braskem S.A., III Pólo Petroquímico, Via Oeste,Triunfo,Brazil;3.Laboratório Nacional de Luz Síncrotron,Campinas,Brazil;4.Department of Chemistry,McGill University,Montreal,Canada |
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Abstract: | A series of aminopropyl-silica-magnesia hybrid materials has been prepared by the sol–gel method from tetraethoxysilane (TEOS),
magnesium chloride (MgCl2) and aminopropyltriethoxysilane (APTES) under acid conditions. The APTES:TEOS ratio was varied between 0:1 and 1:0. The aminopropyl
coverage concentrations for APTES-silica-Mg samples were in the range of 0.3–2.3 mmol g−1. The hybrid materials were characterized by numerous techniques, including X-ray photoelectron spectroscopy (XPS), Fourier
transform infrared spectroscopy (FT-IR), Fourier transform Raman spectroscopy (FT-Raman), solid-state 13C and 29Si nuclear magnetic resonance (13C- and 29Si-NMR), thermogravimetry (TGA), N2 adsorption–desorption, small-angle X-ray scattering (SAXS), and scanning electron microscopy (SEM). The increase of APTES
content in the silica network resulted in the increase of six-membered siloxane rings. The hybrid systems were shown to be
formed from fully-condensed, trifunctional APTES species. The porosity and morphology of the hybrid materials were influenced
by the initial TEOS/APTES ratio. The radius of gyration of the primary particles, determined by SAXS, was between 1.1 and
2.9 nm. |
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