Silicone rubber has extensive and crucial applications in the aerospace field.
I. Sealing materials
Although silicone rubber has slightly inferior mechanical strength at room temperature compared to other rubbers, it exhibits excellent performance in harsh environments. With its characteristics such as high elasticity, resistance to high and low temperatures, aging resistance, and biocompatibility, it becomes an important material in the aerospace field. Silicone rubber adhesives can be used for flexible bonding and thermal insulation sealing between the structural layer and insulation layer of aircraft. Solid silicone rubber sealing materials are found in every corner of the aerospace industry and are used for sealing in areas such as rocket body windows, spacecraft docking, and gas systems. For example, silicone rubber sealing rings and gaskets play an important role in isolating the engine compartment from the external environment. The silicone rubber sealing materials developed by the Aerospace Materials and Technology Research Institute have outstanding heat resistance and cold resistance. The long-term service temperature is from -60°C to 250°C. For short-term use, it can exceed 300°C. It can withstand high-temperature ablation exceeding 3000K instantaneously and has excellent properties such as resistance to ozone, sunlight, mold, and seawater.
II. Damping materials
The damping mechanism of silicone rubber damping materials is as follows: when polymer viscoelastic materials are subjected to stress and strain, the bent molecular chains will undergo deformation such as stretching and bending, and there will also be torsion and slippage between molecular chains. After the external force disappears, the elastic part causes some molecular chains to return to their original positions, while the viscous part makes the slippage between chain segments unable to fully recover, resulting in permanent deformation and thus causing some energy to be consumed in the form of heat. Although silicone rubber originally has a relatively small damping loss as a damping material, with the emergence of new high-damping silicone rubber materials and the application of new blending technologies, it is gradually replacing traditional butyl rubber and becoming the first choice in aerospace damping and vibration reduction structures, with increasingly widespread applications, such as in shockproof materials for heat sinks and instrument damping systems. In the past decade or so, significant progress has been made in the research and development and application of silicone rubber damping materials. The developed wide-temperature and wide-frequency high-damping materials have a damping coefficient β≥0.3 in the temperature range of -50°C to 150°C.
III. Thermal conductive damping materials
With the increasing integration of electronic equipment in aerospace products, the power and heat generation are getting larger and larger, requiring efficient heat dissipation. When performing damping and vibration reduction treatment on the structure, it is necessary to improve the vibration mechanical environment of electronic equipment and meet the heat dissipation requirements. This makes thermal conductive damping materials crucial. And silicone rubber also has broad application prospects in this regard.