Silicone rubber is a high-polymer elastic material with both inorganic and organic properties. Its molecular main chain consists of alternating silicon (Si) and oxygen (O) atoms (-Si-O-Si-), with side chains connected to silicon atoms, which are carbon-hydrogen or substituted carbon-hydrogen organic groups. These groups can be methyl, unsaturated vinyl (usually not exceeding 0.05 mole fraction), or other organic groups. The low degree of unsaturation in this molecular structure gives silicone rubber excellent heat aging resistance, weather aging resistance, UV resistance, and ozone resistance. The flexibility of the molecular chains and weak intermolecular forces between them make vulcanized silicone rubber soft and elastic, although it may have relatively poor physical properties.

    Silicone rubber development began in the 1940s. The earliest varieties researched abroad were dimethyl silicone rubber. Around 1944, both Dow Corning and General Electric in the United States began production. China successfully conducted research and started industrial production in the early 1960s. Today, countries producing silicone rubber include China, the United States, the United Kingdom, Japan, the former Soviet Union, Germany, and others, with over 1,000 different grades and brands.

 Applications: Silicone rubber possesses unique comprehensive properties, especially its biocompatibility, which is a critical characteristic. It has been successfully used in applications where other rubbers are ineffective, solving many technical problems and meeting various needs in modern industry and daily life. Like other rubbers, silicone rubber can be processed into various shapes, profiles, hoses, strips, rollers, and sheets. Room-temperature vulcanized silicone rubber can be easily used for large-area construction in situ.

(1) Automotive Industry: Silicone rubber's application in the automotive industry is growing rapidly. Silicone rubber, especially those with various properties, can resist the corrosion of fuel and lubricants, improve the performance of various automotive components, and reduce maintenance costs. It can be used for automotive ignition wires, spark plug boots, hoses for heating and cooling systems, muffler liners, battery terminals, and fuel pumps made from fluorosilicone rubber. With the development of vehicle electrification, room-temperature vulcanized silicone rubber is widely used as potting materials for electronic components, windshield seals, body perimeter sealing, and adhesive sealants for rearview mirrors.

(2) Electronics and Electrical Industry: The electronics and electrical industry is one of the earliest and largest consumers of silicone rubber as an insulating material. Silicone rubber is primarily used for TV anode caps, high-voltage protection caps, high-voltage lead wires, refrigerator defrosting wires, power or signal transmission wires and cables, among others. Insulators made from silicone rubber are replacing ceramic products and are widely used in power transmission lines, especially ultra-high-voltage lines. Conductive silicone rubber is used for electrical contacts in electronic computers, telephones, and liquid crystal display touchpoints. Flame-retardant and radiation-resistant silicone rubber is extensively used in wires and cables for nuclear power plants. Silicone rubber heating elements and tapes are employed to control the working temperature of various precision instruments and oil pipelines, and as therapeutic heating blankets in the medical field. Room-temperature vulcanized silicone rubber serves as a waterproof, moisture-proof, and shock-absorbing potting material. Silicone rubber, due to its resistance to hot detergent solutions, is now widely used for pump seals in dishwashers and washing machines. Silicone rubber is highly suitable for use as gaskets in coffee pots, electric frying pans, and steam irons, offering noise isolation and comfort when used as cushions for stereo headphones on the ears and head.

(3) Aerospace Industry Silicone rubber is an indispensable high-performance material in the aerospace industry. It can withstand the extreme cold of outer space and the scorching heat upon re-entry into the Earth's atmosphere. It extends the lifespan of aircraft components, reduces maintenance costs, and minimizes the risk of accidents. Silicone rubber is primarily used for aerospace applications, including sealing of aircraft body panel openings, electrical connectors, sealing switches, dust and water-resistant covers, gaskets, O-ring seals for jet engines and hydraulic systems, oxygen masks, control diaphragms, hot air ducts, and radar wireless shock absorbers. Flame-resistant silicone rubber is suitable for use in rocket fuel valves, power cable insulation, and coatings for rocket launch pad covers to protect against the intense heat of rocket exhaust. Room-temperature vulcanized silicone rubber serves as a sealing material for airtight compartments, window frames, as well as shock-absorbing and moisture-sealing materials.

(4) Building Industry Rubber possesses excellent weather resistance and workability, making it widely used as an adhesive and sealing material in the construction industry, surpassing other types of sealants. In recent years, low modulus, high elongation, two-component sealants have been developed for use in sealing joints in large-scale construction elements such as mobile concrete prefabricated components and curtain walls. Room-temperature vulcanized silicone rubber is also employed for sealing asbestos-cement board joints, bathroom tile gaps, and plumbing fixtures. As rubber prices continue to decrease, its applications will further expand, including potential replacements for asphalt and chloroprene rubber in road joint applications. High-temperature vulcanized silicone rubber sponge strips are used as seals for doors and windows in buildings.

(5) Medical Field Rubber exhibits excellent biocompatibility, minimal reactivity with the body, stability, low blood clotting potential, and the ability to withstand repeated high-temperature and high-pressure sterilization. It can also be processed into various shapes and products such as films, sponges, and airbags, making it one of the most widely used materials in the field of medicine.

(6) Other Fields In addition to the aforementioned applications, silicone rubber has seen a significant increase in its use in fields such as textiles, printing, machinery, plastics, chemicals, papermaking, food processing, and cosmetics. Typical products include rollers made from silicone rubber used for heat setting, embossing, and laminating in the textile and plastic industries. Silicone rubber films are used to create controlled atmosphere windows for storing fruits and vegetables. Furthermore, silicone rubber has demonstrated excellent performance as a sealing material in textile high-temperature equipment and in equipment exposed to high concentrations of alkali, sodium hypochlorite, and hydrogen peroxide.

    Recent Advances in Silicone Rubber Research Silicone rubber possesses excellent resistance to high and low temperatures, ozone, oxygen, UV radiation, and weather aging. It also exhibits outstanding electrical insulation properties, special surface characteristics, physiological inertness, and high breathability, making it widely applicable. However, silicone rubber tends to have low tensile and tear strength, poor resistance to acids and bases, and subpar processing performance when manufacturing complex products. In recent years, various countries around the world have conducted extensive research to address these limitations and have achieved some notable results.

(1) By employing copolymerization (blending) of organosilicon with other monomers or polymers, new copolymers (blends) have been developed. For instance, segmental copolymers of organosilicon and polycarbonate can be used as selectively breathable membranes. Blending organosilicon with ethylene-propylene rubber yields materials with properties intermediate between silicone rubber and ethylene-propylene rubber. Blending silicone rubber with EVA (ethylene-vinyl acetate) results in materials with excellent physical properties, electrical properties, resistance to high-temperature aging, and thermal shrinkage. Proper formulations can impart excellent flame retardancy. Utilizing high-temperature-resistant silicone rubber and high-tensile-strength PMMA (polymethyl methacrylate) to create interpenetrating polymer networks has improved the strength of silicone rubber and the heat resistance of PMMA. Synthesizing polydimethylsiloxane (PDMS)/polystyrene (PS) interpenetrating polymer networks has enhanced the mechanical and elastic properties of organosilicon networks.

(2) Through improved compounding techniques, various specialized silicone rubber formulations with high strength, high tear resistance, low compression set, and resistance to high and low temperatures, flame retardancy, thermal conductivity, and thermal shrinkage have been developed.

（3）In terms of improving processing properties, developments include the formulation of single-stage vulcanization silicone rubber, particle silicone rubber (also known as powdered rubber), and the establishment of a silicone rubber liquid injection molding system based on the catalytic addition reaction between vinyl-containing polysiloxane and hydrogen-containing polysiloxane. The use of addition-type two-component systems has resulted in silicone rubber with excellent thixotropic properties, outstanding processing performance, and user-friendly characteristics, particularly in applications like putty-type mold-making.