Rubber Silica, commonly known as silicone rubber, is a polymer elastic material that combines both inorganic and organic properties. Since the 1950s, silicone rubber has been widely used in various fields such as medical, aerospace, automotive, and electronics due to its exceptional performance. This article will delve into the characteristics and applications of silicone rubber to help readers better understand this high-performance material.
Molecular Structure and Characteristics of Silicone Rubber
The molecular backbone of silicone rubber consists of alternating silicon and oxygen atoms (-Si-O-Si-), which gives silicone rubber its outstanding thermal stability and chemical stability. Silicone rubber exhibits excellent high and low-temperature resistance, operating within a range of -100°C to 350°C, making it an ideal choice for various extreme environments.
Furthermore, silicone rubber boasts excellent electrical insulation, weather resistance, ozone resistance, gas permeability, high transparency, tear strength, heat dissipation, as well as superior adhesion, fluidity, and demolding properties. Some special silicone rubbers also have oil resistance, solvent resistance, radiation resistance, and other characteristics, further broadening their application fields.
Types of Silicone Rubber
Based on differences in molecular structure and characteristics, silicone rubber can be classified into several types:
1. Dimethyl Silicone Rubber: The first silicone rubber to be commercialized, it maintains good elasticity within a temperature range of -60°C to 200°C, exhibits excellent aging resistance, and possesses superior electrical insulation properties, moisture resistance, shock resistance, and physiological inertness.
2. Methyl Vinyl Silicone Rubber: By introducing vinyl groups into dimethyl silicone rubber, its vulcanization processing performance is improved, with a wider operating temperature range (-60°C to 260°C), lower compression set, better solvent swelling resistance, and stability under high-pressure steam.
3. Methyl Phenyl Vinyl Silicone Rubber: Introducing methylphenyl siloxane chains or diphenyl siloxane chains into the molecular chain of methyl vinyl silicone rubber enhances its low-temperature resistance, ablation resistance, and radiation resistance.
4. Fluorosilicone Rubber: It exhibits excellent chemical resistance, solvent resistance, and lubricant resistance, as well as good cold resistance and thermal stability, suitable for parts in contact with fuel oil and lubricating oil.
5. Nitrile Silicone Rubber: The introduction of strongly polar groups on the molecular side chain improves its oil and solvent resistance while enhancing cold resistance.
Applications of Silicone Rubber
The widespread application of silicone rubber is attributed to its unique properties and diverse types:
1. Medical Field: Due to its good biocompatibility and plasticity, silicone rubber is widely used in medical devices, such as prosthetics, heart valves, blood oxygenators, renal dialysis components, intravenous drug and blood transfusion systems, respirators, ventilation masks, etc.
2. Aerospace: Silicone rubber's high and low-temperature resistance and radiation resistance make it an important material in the aerospace industry and cutting-edge technologies, used in the manufacture of cold-resistant rubber, seals, gaskets, and heat-shrinkable tubes.
3. Automotive and Transportation: Silicone rubber plays a crucial role in the protection, sealing, and insulation of automotive electrical components and is also used in other transportation modes for parts resistant to oil and solvents.
4. Electronics and Electrical: Silicone rubber's high transparency, electrical insulation, and heat resistance make it an ideal choice for encapsulating electronic components, advanced insulation materials, and dynamic seals.
Limitations and Improvements of Silicone Rubber
Despite its many advantages, silicone rubber has limitations in certain applications. For example, its hydrophobic nature results in greater friction resistance when in contact with human tissues, requiring additional lubricants or hydrophilic lubricating coatings on the surface. Additionally, silicone rubber faces the risk of thrombosis when in long-term contact with blood, and new silicone rubber products are being developed with anticoagulant coatings to improve blood compatibility.
In summary, silicone rubber (Rubber Silica) as a high-performance material plays a significant role in multiple fields. With continuous technological advancements and deeper exploration of applications, the performance of silicone rubber will further improve, and its application fields will become even more extensive.