Preparation and characterization of montmorillonite modified with 3-aminopropyltriethoxysilane

The modification of montmorillonite clay mineral (Mt) was performed using the 3-aminopropyltriethoxysilane (γ-APS) silylation agent in different synthesis solutions. The modified products (S-Mt) were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy. The XRD demonstrated that silane was intercalated in the interlayer space of Mt due to the increase in basal spacing. The basal spacing shown by some S-Mts suggests the presence of a double layer of aminopropyl molecules in the interlayer space of the clay mineral modified in water and in a hydroalcoholic media at both synthesis temperatures (50 °C and 80 °C). The TGA revealed the presence of peaks in the range of 200 °C to 600 °C due to the presence of adsorbed silanes, intercalated silanes and silanes chemically bonded between the clay mineral layers and/or the edges. Evidence showed that the presence of water in dispersant is essential for intercalation of the silane in the interlayer space of the Mt such that the S-MMTwater, S-MtE/A(50) e S-MtE/A(80) showed higher amount of silane and higher basal spacing in its structure. Qualitative evidence of the presence of γ-APS in the modified clay minerals was obtained by FTIR spectroscopy.