CHEMICAL MODIFICATION AND CHARACTERIZATION OF BOEHMITE PARTICLES

Polymerizable organic silane molecules 3-(trimethoxysilyl)propylmethacrylate (3MPS) and vinyltri(2-methoxyethoxy)silane (VTMES) have been introduced onto surfaces of high purity Boehmite (a commercial alumina) via hydroxyl groups on the oxides in order to obtain organic-inorganic hybrid "macromonomers". Changes of surface characteristics have been determined using thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR). The influence of the type of silane used and modification conditions have been determined. Preheating was applied to some Boehmite samples; it leads to lower concentrations of OH groups on the powder surface and the adsorption yields lower than in samples without preheating. Modification leads to surface hydrophobicity and thus reduces significantly water adsorption; in TGA we see desorption of water below 423 K only in un-modified Boehmite.