Effect of stearic acid and sodium stearate on hydrophobicity of nano calcium carbonate and mechanism of water vapor adsorption

Abstract It is essential to understand the modification mechanism of hydrophobicity nano-CaCO3 to their potential application in different fields of chemistry. However, the water absorption of hydrophobicity nano-CaCO3 is seldom studied. In this study, Raman, BET and TGA experiments were performed on nano-CaCO3 samples to obtain surfactants contents and microstructure characteristics. SEM, TEM and DSL results showed that the nano-CaCO3 modified by stearic acid and sodium stearate had larger particle size and smaller nanoclusters. In the water vapor adsorption test, the order of saturation adsorption capacity was nano-CaCO3(PCC) > nano-CaCO3 modified by sodium stearate(PCC-Sa-Na) > nano-CaCO3 modified by stearic acid(PCC-Sa), and XPS results showed that PCC-Sa had more hydrophobic groups than PCC-Sa-Na, which also explained that the hydrophobicity of PCC modified by stearic acid and sodium stearate was improved by increasing the hydrophobic bond on the surface of CaCO3 and reducing the hydrophilic groups. Our analysis provides a path for the design and the prediction of hydrophobicity of nano-CaCO3, which is the main focus of our work.