1. Chemical structure of silica 
95~99% of silica is SiO2. X-ray diffraction confirms that the structure of white carbon black is different due to different preparation methods. The internal structure of fumed silica is almost completely a three-dimensional network structure of closely arranged silicic acid, which makes particles less hygroscopic, with strong surface adsorption and strong reinforcement. In the structure of precipitated silica, in addition to generating silicic acid with three-dimensional structure, there are still many silicic acid with two-dimensional structure, which leads to loose structure, many capillary structures and easy moisture absorption, thus reducing its reinforcement activity.

2. Structure of silica 
The structure of silica is like carbon black, and its basic particles are spherical. In the production process, these basic particles collide with each other at high temperature to form a chain branch structure connected by chemical bonds, which is called the basic aggregate. The chain dendritic structures adsorb each other by hydrogen bond to form a secondary aggregate structure, which is easy to be destroyed during processing and mixing