Surface-modified quantity of Fe3O4 particles by thermogravimetric analysis

Different Fe3O4 particles are synthesised with silane and carboxylic acid, surface modified by co-precipitation, and subsequently are characterised by Fourier transform infrared spectroscopy, wide-angle X-ray diffraction, laser particle size analyser (LPSA) and thermogravimetric analyser (TG). Based on the LPSA results, Fe3O4 particles are micrometre size due to the experimental condition and modifiers. It is therefore suggested that the vacuum freeze-drying and the long-chain modifiers tend to obtain small size particles. The modifiers density on the surface of Fe3O4 particles is obtained by TG and formula calculation. It is shown that the silane coupling agent is more effective modifier for Fe3O4 particles compared with carboxylic acid. In accordance with the molecular structure and functional group number of carboxylic acids, different carboxylic acids have different modifiers density.