Surface Modification of Magnetic Mesoporous Systems with Aminopropyl Groups and Their Properties

Iron oxide silica Fe x O y -SiO 2 composite systems with aminopropyl (AP) groups on the surface have been synthesized via different routes. The surface modified samples have been studied by X-ray diffraction (XRD) analysis and IR spectroscopy. Magnetic phases of iron oxides have been detected after post-synthetic grafting of AP groups onto the surface of these composite systems. Magnetic properties of these samples have been determined. Only insignificant reduction in the material saturation magnetization and remanent magnetization have been registered upon surface grafting procedure. This approach has been considered to be successful as magnetic properties of the substrate were preserved. Amount of aminoalkyl groups grafted onto the silica composite surface has been determined by thermogravimetric analysis. The mass fraction of grafted aminoalkyl groups has been found to be dependent on the textural properties of the composite sample.