Fumed silica has a significant effect on improving the tear resistance of rubber products, which is mainly reflected in the following aspects:

1. Physical and chemical properties
High purity and fine particle size: Fumed silica, that is, fumed silica, has a silica content of more than 99.8%, and a small average particle size. The average diameter of the primary particles is between 7-40nm. This high purity and fine particle size feature makes fumed silica more dispersible and has a higher specific surface area in rubber, thereby improving its bonding with the rubber matrix.
Strong adsorption and reinforcement: Fumed silica has strong surface adsorption, which can effectively adsorb free radicals and acidic substances in rubber to prevent rubber aging. At the same time, its internal structure is tight and almost completely arranged in a three-dimensional structure, which makes it have a strong reinforcement effect in rubber and can significantly improve the mechanical properties of rubber products.

2. Specific improvement of the tear resistance of rubber products
Improved tear resistance: The tear resistance of rubber products reinforced with fumed silica can be significantly improved. In large-size tire tread rubber, about 10-25 parts of fumed silica are usually added to significantly improve the tire tread's resistance to cutting, chipping and cracking. This improvement effect is reflected in a variety of application scenarios of rubber products.

Improved wear resistance: The small particle size and high fluidity of fumed silica make it more evenly distributed in rubber, which helps to form a denser and cleaner material surface, thereby reducing the friction coefficient and improving wear resistance. This is especially important for rubber products that need to withstand high friction and wear.

Improved vulcanization efficiency: Fumed silica can also be used as a catalyst to accelerate the vulcanization reaction of rubber, shorten the vulcanization time, and improve production efficiency. At the same time, its good dispersibility also helps the uniform cross-linking of rubber molecular chains during the vulcanization process, thereby further improving the mechanical properties of rubber products.
Enhanced interfacial bonding: The surface of fumed silica has active silanols, which can form strong chemical bonds with other materials, thereby enhancing the bonding strength between rubber and skeleton materials (such as cotton, nylon, polyester, steel wire, etc.). This is of great significance for improving the overall performance and service life of rubber products.

3. Precautions in practical applications
Reasonable control of dosage: Although fumed silica can significantly improve the tear resistance of rubber products, excessive use may cause the rubber to be too hard, affecting elasticity and flexibility. Therefore, in practical applications, it is necessary to reasonably control the amount of fumed silica.

Modification: In order to improve the dispersibility and reinforcement effect of fumed silica in rubber, it is sometimes necessary to modify it. For example, using silane coupling agent to modify silica can change its hydrophilicity to hydrophobicity, further improving its reinforcement effect in rubber.

In summary, fumed silica has become one of the important materials for improving the tear resistance of rubber products through its unique physical and chemical properties and its effect on improving the various properties of rubber products. In practical applications, it is necessary to make reasonable selection and use according to specific needs and conditions.