The surface of white carbon black has strong chemisorption, which is related to the existence of its surface hydroxyl. Its surface hydroxyl can combine with molecules in the form of hydrogen bond to form a multi-molecular adsorption layer. Moreover, with the increase of surface hydroxyl density of white carbon black, the amount of water adsorbed also increases, which can be reflected from the relationship between moisture absorption and surface area, and the adsorption amount is proportional to the surface area of white carbon black.


If the silanol group of white carbon black is far away from the hydrogen bond formed by a water molecule, a water molecule can only interact with one silanol group. However, with the increase of the density of silanol groups, each hydrogen atom of water molecules can interact with a silanol group, which means that water molecules have strong bonds.