Many inorganic powder materials possess a large number of surface hydroxyl groups, rendering them highly hydrophilic. This characteristic leads to moisture absorption and agglomeration, which can compromise the performance of the final product.

Hexamethyldisilazane (HMDS) is a classic hydrophobizing agent. The active groups within its molecules undergo condensation reactions with the hydroxyl groups on the surface of inorganic materials, transforming the surface into an organosilicon structure rich in methyl groups.

Following treatment, the material's surface energy is significantly reduced, resulting in excellent hydrophobic properties. Water droplets do not readily adhere to the surface, and the flowability of the powder is markedly improved.

This technology is widely applied to materials such as silica (white carbon black), diatomaceous earth, titanium dioxide, and various nanopowders. HMDS-modified materials find use in diverse sectors, including coatings, rubber, plastics, electronic materials, and construction materials.

Although surface modification is merely a single processing step, it can substantially enhance the material's added value, and HMDS serves as a crucial tool in achieving this transformation.