Preparation and characterization of ultra-hydrophobic calcium carbonate nanoparticles

Anionic surfactants based on fatty acids are usually used to modify the particle surface properties of CaCO3 with the aim to enhance its dispersion and compatibility with polymer matrices. In this study sodium oleate was used for the preparation of ultra-hydrophobic CaCO3 nanoparticles using a wet carbonation route. The effect of sodium oleate on the characteristics, particle size, morphology, surface potential, thermal decomposition and hydrophobicity of CaCO3, was investigated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), Zeta potential, thermogravimetric analysis (TGA) and water contact angle measurement (WCA). The results showed that the addition of 2 wt% sodium oleate helps in reducing the particle size from 2 mu m length scalenohedral particles to 45 nm rhombohedral particles and modifying of the hydrophobic property of CaCO3.