Abstract: Nanosizing and surface modification of Na-MMT were carried out using hydroxysilicone oil via mechanical ball milling techniques, and chitosan was phosphorylated. The phosphorylated chitosan was further applied to decorate exfoliated montmorillonite under oil bath treatment. The crystal structure, surface characteristics, specific surface area and thermal stability of MMT before and after surface modification with phosphorylated chitosan were systematically studied using X-ray diffraction (XRD), Fourier transform infrared absorption spectroscopy (FT-IR), contact angle measurement (CA), specific surface area and pore size analyzer (BET), and thermogravimetric analyzer (TGA). The results showed that after modification with hydroxysilicone oil and surface coating with phosphorylated chitosan, the crystal structure of MMT does not significantly changes. Nevertheless, the diffraction peak corresponding to the (001) crystal plane is widened, which means that the layered structure of Na-MMT is deteriorated and exfoliated. Furthermore, the surface hydrophobicity of MMT coated by phosphorylated chitosan is improved, with a water contact angle of 62.7°, and a specific surface area of 13.812 m²/g. In short, the phosphorylated chitosan presents a thicker coating layer on the surface of Na-MMT.

Key words: Na-MMT, phosphorylated chitosan, nanosizing, surface properties