Silane coupling agent is a kind of alkoxysilane. Its alkoxy group will hydrolyze with water and become hydroxysilane (i.e. silanol). At the same time, it will release the corresponding alcohol (methanol will be released after the hydrolysis of methoxy silane, and ethanol will be released after the hydrolysis of ethoxysilane), which is the by-product of the reaction. This reaction is the hydrolysis reaction of silane coupling agent, and the factors affecting the speed of this reaction are as follows:

1. Concentration of silane coupling agent in water: As with general chemical reactions, the greater the concentration of reactants, the faster the chemical reaction. Therefore, higher silane coupling agent will speed up the hydrolysis reaction, and of course, it will also speed up the self polymerization of hydrolysis products.

2. PH of silane coupling agent aqueous solution: when the pH of the aqueous solution is equal to 7, that is, neutral, the hydrolysis reaction of silane coupling agent is the slowest, and the acid or base has a significant catalytic acceleration effect on the hydrolysis reaction of silane coupling agent, so generally, the pH of the solution should be adjusted to 3~5 with acid before dropping silane coupling agent; However, the aqueous solution of aminosilane is inherently alkaline, so aminosilane is generally directly dripped without using acid to adjust the pH value of the aqueous solution.

3. Solubility of silane coupling agents in water: different polarity of silane coupling agents also have different solubility in water. Because silane coupling agents with higher solubility dissolve more in water and fully contact with water, their hydrolysis speed will be relatively fast. In order to achieve this goal, it is very necessary and important to fully stir the silane coupling agent when it is dissolved in water.

4. Temperature: Like general chemical reactions, the speed of hydrolysis reaction of silane coupling agent has a positive correlation with the temperature, that is, the higher the temperature, the faster the speed. Therefore, in summer and winter, the change of ambient temperature will also affect the hydrolysis rate of silane coupling agent.

5. Alcohol cosolvent: Like common chemical reactions, if some products are added to the reactants, the existence of the products will slow down the chemical reaction, and the chemical reaction is partially reversible. If some alcohol solvents, such as ethanol, are added to the solution, the hydrolysis reaction rate of silane coupling agent will be slowed down.