In the field of materials science, a deep understanding of the internal relationship between the evolution mechanism of the microstructure of silicone rubber and its properties is crucial for the development of high-performance silicone rubber materials. The properties of silicone rubber largely depend on its microstructural characteristics, and the action of external factors will trigger dynamic changes in the microstructure, which in turn affects its performance.

At the molecular level, the main chain of silicone rubber is composed of silicon-oxygen bonds (Si-O), and this chemical bond endows silicone rubber with basic stability and flexibility. However, when silicone rubber is affected by external factors such as heat, mechanical stress, and chemical reagents, the molecular chains will undergo a series of changes. Under the action of heat, an increase in temperature will intensify the thermal motion of the molecular chains. When the temperature reaches a certain level, the silicon-oxygen bonds may break, leading to the degradation of the molecular chains. At the same time, cross-linking may occur between the molecular chains through free radical reactions, forming a more complex network structure. For example, during the high-temperature vulcanization process, the molecular chains of silicone rubber form a three-dimensional network through cross-linking reactions, and its cross-linking density directly affects the properties of the material such as hardness and tensile strength. Moderately increasing the cross-linking density can improve the mechanical strength of silicone rubber, but an excessively high cross-linking density will limit the movement of the molecular chains, making the material hard and brittle and losing some of its flexibility.
The influence of mechanical stress on the microstructure of silicone rubber is also very significant. Under the action of mechanical stresses such as tension and compression, the molecular chains of silicone rubber will undergo orientation alignment. When subjected to tensile stress, the originally disordered molecular chains gradually stretch and align along the direction of the stress, forming an orientation structure. This orientation structure is manifested microscopically as the preferred orientation of the molecular chains, and macroscopically, it enhances the mechanical properties of the material in the orientation direction, such as an increase in tensile strength. However, when the stress exceeds a certain limit, the molecular chains may break, leading to the deterioration of the material's properties. Through the real-time observation of the changes in the microstructure of silicone rubber during the stretching process, such as using synchrotron radiation X-ray scattering technology, it is possible to clearly observe the orientation process of the molecular chains from disorder to order and the microscopic mechanism of fracture, providing an intuitive basis for understanding the performance changes of the material under mechanical stress.
Chemical reagents can also change the microstructure of silicone rubber. Certain chemical reagents may react chemically with the molecular chains of silicone rubber. For example, strong oxidants will cause the side groups on the molecular chains of silicone rubber to undergo oxidation reactions, destroying the chemical structure of the molecular chains. Some small-molecule solvents may penetrate into the interior of the silicone rubber, increasing the distance between the molecular chains and causing the material to swell. This swelling phenomenon not only changes the microstructure of the silicone rubber but also affects its mechanical properties, electrical properties, etc. For example, the hardness of the swollen silicone rubber decreases, and its electrical insulation performance may also decline. Studying the interaction mechanism between chemical reagents and the microstructure of silicone rubber is of great significance for predicting the performance changes of silicone rubber in different chemical environments and helps to select suitable silicone rubber materials for actual application scenarios.


110 Methyl Vinyl Silicone Gum