The mechanism by which gas-phase silica enhances rubber properties in the rubber industry is mainly reflected in the following aspects:
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1. Reinforcing effect
Gaseous silica has a very high specific surface area (usually between 150-380 m ²/g) and nanoscale particle size (7-40 nanometers), which can significantly improve the mechanical properties of rubber. The silicon hydroxyl groups (Si OH) on its surface can form physical or chemical bonds with rubber macromolecules, forming a uniform network structure. This network structure can effectively disperse stress, improve the tensile strength, tear strength, and wear resistance of rubber.

2. Improve rheological properties
Gas phase silica can improve the rheological properties of rubber, giving it better flowability and dispersibility during processing. Its high specific surface area and surface activity enable it to form a stable three-dimensional network in the rubber matrix, thereby improving the thixotropy and thickening effect of rubber. This characteristic is particularly important for room temperature vulcanized (RTV) silicone rubber, as it can maintain the viscosity and flowability before vulcanization.

3. Improve dimensional stability and aging resistance
The addition of fumed silica can improve the dimensional stability and aging resistance of rubber products. Its nanoscale particles can be uniformly dispersed in the rubber matrix, forming a dense protective layer, thereby reducing the erosion of the rubber by the external environment. This protective layer can effectively prevent thermal oxidation aging and ultraviolet aging of rubber, extending the service life of rubber products.

4. Enhance anti slip properties
In tire rubber, fumed silica can significantly improve the rubber's wet skid resistance. This is because the high specific surface area and surface activity of fumed silica enable it to form a uniform adsorption layer on the rubber surface, increasing the friction between the rubber and the ground. This characteristic is particularly important for high-performance "green tires", which can effectively shorten braking distance and improve driving safety.

5. Improve interface compatibility
The surface of fumed silica can be hydrophobized through chemical modification (such as silane coupling agent treatment) to improve its compatibility with organic rubber substrates. This modification can enhance the dispersibility of gas-phase silica in rubber, further improving the mechanical properties of rubber. For example, hydrophobic fumed silica has better dispersibility in liquid polysulfide rubber than hydrophilic fumed silica, which can significantly improve the tensile strength of the sealant.

6. Reduce rolling resistance
In tire manufacturing, the use of fumed silica can reduce the rolling resistance of tires. This is because its nanoscale particles can form a uniform network structure in the rubber matrix, reducing the friction of rubber molecular chains. This characteristic is of great significance for improving fuel economy and reducing exhaust emissions.
In conclusion, through its high specific surface area, nanometer particle size and surface activity, fumed silica can significantly enhance the mechanical properties, rheological properties and anti-aging properties of rubber in the rubber industry, while improving interface compatibility and reducing rolling resistance.