Aminated phyllosilicates synthesized via a sol-gel process

Three analogous phyllosilicates were synthesized via a sol-gel process from the reaction of magnesium ions with aminated trialkoxysilanes in an aqueous basic medium at 373 K. The inorganic-organic hybrids obtained, designated as SILMgx (x = 1-3) are related to [3-aminopropyl]-, [N-(2-aminoethyl)-3-aminopropyl]-, and [(10-amino)-4,7-diazanonyl]trimethoxysilane, respectively. The elemental analysis of the se hybrids gave the following C/N ratios: 3.1, 2.5, and 2.4. Thermal analysis data showed 50.7, 56.2, and 58.0% weight losses for the same sequence of hybrids. However, the thermal stability decreased in the order SILMg1 > SILMg2 > SILMg3. The surface areas of these matrixes are <2.0 m(2) g(-1) and X-ray diffraction patterns gave lamellar distances of 1745, 2063, and 2323 pm for SILMgx (x = 1-3). The infrared data indicated the existence of a phyllosilicate structure with absorption at 540 cm(-1), which is associated with vibration of the Mg-O group. Si-29 NMR showed the presence of three silicon species: T-1, T-2, and T-3 in the inorganic-organic backbone structure. The photomicrographs obtained by scanning electron microscopy showed in all cases well-formed particles that have irregular shapes and particle sizes.