When your phone is charging, the temperature of its casing remains controllable; after ten years of use, the sealant in household appliances still maintains its effectiveness; and batteries for new-energy vehicles operate reliably under both high and low temperatures—all these scenarios are made possible thanks to a key material: silicone. Combining the flexibility of rubber with the ease of processing typical of plastics, silicone boasts three core properties—thermal conductivity, electrical insulation, and resistance to aging—that enable its widespread application across industries such as electronics, automotive, construction, and aerospace. Today, we’ll delve into the core performance advantages of silicone and explore the reasons behind its outstanding capabilities.

1. Thermal Conductivity, Not Electrical Conductivity: The “Thermal Management Guardian” for Electronic Devices

Today, as electronic devices become increasingly miniaturized and high-powered, thermal management has emerged as a core technical challenge. Devices must promptly dissipate the heat generated by components during operation to prevent overheating, which could lead to lagging performance or damage. At the same time, the materials used must maintain electrical insulation to mitigate the risk of short circuits. Silicone happens to be perfectly suited to meet these critical requirements.

The reason silicones can conduct heat but not electricity lies in their unique molecular structure and advanced modification techniques. From a fundamental structural perspective, the main chain of silicones consists of alternating silicon-oxygen bonds formed by silicon and oxygen atoms. This structure inherently possesses excellent insulating properties, making it difficult for electrons to move along the molecular chain and thus preventing electrical conduction. As for thermal conductivity, it is achieved through filler modification: by incorporating inorganic thermally conductive fillers such as aluminum oxide, boron nitride, and silicon carbide into the silicone matrix, a continuous thermal-conducting pathway is established, enabling heat to rapidly transfer from high-temperature regions to low-temperature regions.

More importantly, silicone possesses excellent flexibility and conformability. Modified thermally conductive silicones—such as thermally conductive silicone pads and thermally conductive potting compounds—can closely adhere to the irregular surfaces of electronic components, eliminating air gaps that act as poor thermal conductors and significantly enhancing heat dissipation efficiency. Typical applications include thermally conductive silicone between mobile phone chips and heat sinks, as well as thermally conductive potting compounds used in new-energy vehicle battery packs—all of which simultaneously ensure both electrical insulation safety and superior heat dissipation performance.

II. Excellent Insulation Performance: Core Insulation Assurance Under High-Voltage Conditions

In addition to electronic devices, in fields such as high-voltage power, rail transit, and aerospace, “insulation” is a core requirement for ensuring the stable operation of equipment—and the insulating performance of silicone can be described as an “industry benchmark.”

This performance also stems from the unique characteristics of its molecular structure. The silicon-oxygen bond in the silicone backbone has a bond energy as high as 443.5 kJ/mol, significantly greater than the carbon-carbon bond’s 345.6 kJ/mol, making the structure exceptionally stable and resistant to degradation by external factors. Meanwhile, the organic groups—such as methyl groups—on the silicone molecular chain exhibit hydrophobic properties, effectively repelling moisture. Since moisture is a major factor that can degrade insulating performance, especially in humid environments, silicone can maintain a stable insulation resistance, thereby preventing issues like leakage current and dielectric breakdown.

In addition, silicone polymers exhibit excellent arc resistance and corona resistance. Under high-voltage discharge conditions, they are unlikely to carbonize or decompose, enabling them to form a stable protective layer that effectively resists arc erosion. Silicone materials are widely used in insulators for high-voltage transmission lines, insulating coatings for motor windings, and substitutes for transformer insulating oils. Even under prolonged exposure to high voltage and high temperatures, these materials can still ensure insulation stability and reduce the risk of failure.

3. Excellent Aging Resistance: A Reliable Choice for Adapting to Harsh Environments

Under environmental conditions such as prolonged outdoor exposure, alternating high and low temperatures, and chemical corrosion, most materials tend to develop issues like cracking, hardening, and aging failure. In contrast, silicone rubber can maintain stable performance over the long term—this is one of its core advantages that sets it apart from conventional rubbers and plastics.

The aging resistance of silicone fundamentally stems from its stable silicon-oxygen bond structure. On the one hand, the high bond strength of the silicon-oxygen bond makes it difficult for ultraviolet radiation, oxygen, ozone, and other agents to oxidize and decompose it, thereby preventing “photoaging” and “oxidation aging” of the material. On the other hand, silicone’s molecular chains exhibit excellent flexibility; even at low temperatures as low as -50°C, they do not become brittle or crack, and at high temperatures up to 200°C, they neither melt nor decompose, enabling them to withstand a wide range of temperature fluctuations.

Meanwhile, silicone also boasts excellent chemical resistance, enabling it to withstand the corrosive effects of harsh media such as acids, alkalis, and salt spray. Sealing compounds used on building exteriors can maintain their excellent sealing performance even after prolonged exposure to wind, sun, rain, and freezing temperatures. Silicone components installed in automotive engine compartments can last for several years—or even over a decade—under conditions of high temperature and oil contamination. On aerospace equipment, silicone materials continue to function reliably in vacuum and high-radiation environments, ensuring the dependable operation of these devices.

Today, as technology continues to advance, silicone is evolving toward higher thermal conductivity, greater resistance to extreme environments, and increased environmental friendliness, with its application scenarios continuing to expand. From everyday devices like mobile phones and home appliances to new-energy vehicles and 5G base stations, and even to aerospace and deep-sea exploration, silicone plays a vital role in all these fields.