1、Silica surface graft modification
The principle of surface grafting modification method is to graft large polymers with the same properties as the base polymer (e.g. rubber) on the surface of silica by chemical grafting method, which can enhance the force between the particles and the substrate on the one hand and change the polarity of the particle surface on the other hand, and improve the dispersibility of silica itself.
It is suitable for grafting polymers with small molecular weight, and the conditions are harsh when the molecular weight of the grafted polymer is high.
2、Silica coupling agent modification
The principle of coupling agent modification is to use part of the functional groups on the coupling agent to react with the hydroxyl group on the surface of silica, so as to change the structure and distribution of the groups on the surface of silica to improve the compatibility with the substrate as well as its own dispersibility. Coupling agent modification has the advantages of good modification effect and high controllability of reaction, which is one of the most widely used modification methods.
At present, the more widely used coupling agents are silane coupling agent, siloxane coupling agent and silazane coupling agent. The main process of coupling agent modification in practical application is divided into four steps: mixing reaction, cooling separation, repeated washing and precipitation.
3、Silica ionic liquid modification
Ionic liquid, also known as room temperature ionic liquid, is composed of organic cations and organic or inorganic anions, in the liquid state below 100 ℃ molten salt. Ionic liquid modification is the use of ionic liquid modifier instead of the traditional organic phase modifier to modify silica, ionic liquid compared to the traditional organic phase modifier has the advantages of liquid at room temperature, strong electrical conductivity, high stability and good solubility, etc., and it is not volatile, not easy to produce pollution, more in line with the requirements of the green production, but the modification effect is poor.
Ionic liquid modification process is relatively simple, in the mixed system of silica and ionic liquid add a certain amount of anhydrous ethanol and then put into the constant temperature water bath reaction, to be fully reacted and then dried to get modified silica.
4、Silica macromolecule interface modification
The modifier used in macromolecule interface modification is a macromolecule polymer containing polar groups, in the process of modification reaction with silica particles, the main chain of the molecule of macromolecule interface modifier is able to introduce more polar epoxy groups while maintaining the basic structure of the main chain, so as to improve the compatibility of silica particles with the substrate to achieve a better effect of interfacial modification.
This method and coupling agent can be synergistic with each other to strengthen the matrix, but when used alone, the strengthening effect is low.
5、Silica and use modification
Concurrent modification is through silica and other materials and modification, combined with their respective advantages to improve the overall performance of rubber products. This method can combine the advantages of two modifiers to enhance the comprehensive performance of the matrix, but the modification effect is closely related to the ratio of modifiers.
For example, carbon black and silica are good reinforcing agents in the rubber industry, of which carbon black is one of the most commonly used reinforcing agents in the rubber industry. The special structure of carbon black can enhance the tensile and tear strength of the rubber material and improve its abrasion resistance, cold resistance, etc.; while silica as a reinforcing agent can significantly improve the rolling resistance and wet sliding resistance of the rubber product, etc., but the effect is not as good as that of carbon black when used alone. A large number of studies have shown that the use of carbon black and silica as reinforcing agents can combine the advantages of both to improve the overall performance of rubber products.

Room termperature curing polysilazane, pls check IOTA 9150, IOTA 9150A. 
High termperature curing polysilazane, pls check IOTA 9108, IOTA 9118.