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

It is essential to understand the modification mechanism of hydrophobicity nano-CaCO to their potential application in different fields of chemistry. However, the water absorption of hydrophobicity nano-CaCO is seldom studied. In this study, Raman, BET and TGA experiments were performed on nano-CaCO samples to obtain surfactants contents and microstructure characteristics. SEM, TEM and DSL results showed that the nano-CaCO 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-CaCO(PCC) > nano-CaCO modified by sodium stearate(PCC-Sa-Na) > nano-CaCO 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 CaCO and reducing the hydrophilic groups. Our analysis provides a path for the design and the prediction of hydrophobicity of nano-CaCO, which is the main focus of our work.