In the journey of space exploration, the extreme space environment faced by spacecraft poses huge challenges to their materials. Silicone rubber, one of the commonly used materials in spacecraft, undergoes complex performance evolutions under extreme conditions such as vacuum, strong radiation, and alternating extreme cold and high temperatures. In - depth study of these changes and the formulation of corresponding coping strategies are crucial for ensuring the safe operation of spacecraft and extending their service life.

In a vacuum environment, silicone rubber exhibits a degassing phenomenon. Due to the extremely scarce gas molecules in a vacuum environment, low - molecular - weight substances inside the silicone rubber, such as unreacted monomers and plasticizers, gradually escape from the material surface. This not only leads to material mass loss but may also form pollutants inside the spacecraft, affecting the normal operation of optical instruments, electronic devices, etc. For example, if the silicone rubber seals used near the optical lenses of satellites degas severely, the escaped substances will deposit on the lens surface, reducing the resolution and imaging quality of the optical system. To address this issue, researchers optimize the formulation of silicone rubber to reduce the content of volatile components and adopt a high - temperature vacuum treatment process during the production process to remove low - molecular - weight substances from the material in advance, thereby reducing the degassing rate.
Strong radiation is another major characteristic of the space environment. High - energy particles in cosmic rays, such as protons, electrons, and heavy ions, interact with silicone rubber molecules. The high energy of these particles can break the silicone rubber molecular chains, triggering cross - linking or degradation reactions of the molecular chains. Excessive cross - linking will make the silicone rubber hard and brittle, lose elasticity, and lead to a decline in sealing performance; while degradation will greatly reduce the mechanical properties of the material. In the extra - vehicular equipment of the International Space Station, some silicone rubber components have been affected by strong radiation and experienced performance degradation. To improve the radiation resistance of silicone rubber, scientists attempt to add radiation - resistant fillers to silicone rubber, such as nano - titanium dioxide and carbon nanotubes. These fillers can absorb or scatter high - energy particles, reducing their damage to the silicone rubber molecular chains and at the same time enhancing the mechanical properties of the material, achieving a two - for - one effect.
Extreme temperature changes are also a difficult problem that silicone rubber must face in the space environment. When a spacecraft orbits the Earth, the temperature on the sun - facing side can reach above 100 °C, while the temperature on the shaded side can drop sharply to below - 100 °C. Under such drastic temperature alternations, silicone rubber generates internal stress due to thermal expansion and contraction. If the thermal stability of the material is insufficient, repeated thermal cycles will lead to fatigue damage of the molecular chains, and eventually, the material will develop defects such as cracks and delamination. To solve this problem, the development of silicone rubber materials with high thermal stability and a low coefficient of thermal expansion is the key. By modifying the molecular structure of silicone rubber and introducing special high - temperature - resistant groups, such as aryl and heterocyclic groups, the thermal decomposition temperature of the material can be increased, enhancing its stability at high temperatures. At the same time, optimizing the material formulation and adjusting the ratio of fillers to the matrix can reduce the coefficient of thermal expansion of the material and minimize the internal stress caused by temperature changes.


Medium and high voltage insulation silicone rubber