Does Silicone Have Thermal Conductivity?

At Silicone Depot, we offer a wide range of silicone sealants. These materials can help insulate homes and commercial buildings from heat and moisture. But not all silicone is a thermal insulator. In fact, some people choose a specific silicone for its thermal conductivity.

Silicone is a highly versatile material. People use it in everything from sealing fluids to creating circuit boards.

So, now let’s answer the question, “Does silicone have thermal conductivity?” It can be important to pinpoint the various cases in which it does and does not effectively transfer heat. From here, we can explore why.

Like all substances, silicone always has some level of thermal conductivity. However, different forms of silicone can vary wildly in their tendency to conduct heat.

Silicone Thermal Conductivity Varies

Some forms of silicone are specifically designed and used to transfer heat. Some are meant for nearly the opposite purpose.

In the case of silicone sealants, for example, low heat conductivity is typically the desired outcome. Professionals often use it with the intention of blocking air and heat. As a result, they can be relatively low in thermal conductivity.

However, there are applications in which silicone rubber thermal conductivity can be a benefit. One example is heat sink gaskets made for computing. Silicone thermal pads are made of highly heat-conductive silicone and can help keep central and graphics processors in computers from overheating. That’s why silicone can be effective in everything from building computers and advanced electronic systems in high-tech vehicles to sealants for commercial and residential sealing applications.

To better understand the varied thermal properties of silicone materials, let’s explore some of the instances in which silicone is a good thermal conductor and cases where it’s an effective thermal insulator. We’ll also discuss what silicone is, how it differs from silicon, and why this results in a wide variety of silicone substances, each with its own unique thermal properties.

What is Silicone?

So, if silicone is all — silicone — then why does it vary so wildly in terms of heat conductivity? To understand that, it’s important to understand exactly what is silicone. While people often confuse it with silicon — the element from which its name partially derives — they are distinct materials.

Silicone Vs. Silicon

Silicon is a chemical element, while silicone is a material made up of more than one element. Silicone describes a polymer containing both silicon and oxygen. One of the great things about silicone is how versatile it is.

There is a wide range of materials that fall into this category. They’re used in everything from building flexible heat-conducting parts for computers to creating flexible sealants that are capable of sealing off moisture, heat, and air in automotive and building applications.

Silicon, on the other hand, while varied in its applications as well, can have vastly different physical and mechanical properties. Silicon is often used to create circuit boards due to its properties as an effective semiconductor.

Understanding Thermal Conductivity

Another important factor in understanding the thermal properties of silicone is understanding exactly what thermal conductivity is. Thermal conductivity refers to the efficiency with which a material can conduct heat. A material that conducts a lot of heat can absorb heat, transfer the heat across itself, and give off heat easily. This is often done with a high degree of consistency.

Heat-conductive materials are often used when we want to control or facilitate the transfer of heat effectively. For example, copper is a highly heat-conductive element that we often use in cooking. Copper pans heat up and cool down very quickly, giving us a high degree of control.

In electronics, conductive materials are used to carry heat away from heat-generating components such as processors. This helps mitigate the risks of heat damage.

Understanding Thermal Insulation

Thermal insulation, on the other hand, refers to the ability of a material to resist transferring heat. Thermally insulative materials are used in a wide range of applications as well.

For example, winter attire is designed to be thermally insulative, helping us trap heat to stay warm. Home insulation works in a similar way. It is designed to keep our homes at a stable temperature and make better use of climate control.

Thermal insulators can also be used to protect against the potentially damaging effects of excessive heat. For example, oven mitts keep our hands protected so that we can handle cookware at high temperatures. Similarly, silicone heat shielding can be used to insulate fuel lines, electronics, and other heat-sensitive materials around heat sources. Some popular examples include in vehicles, heavy machinery, or kitchens.

Silicone sealants are often designed to be thermally insulative. They’re used to seal cracks and crevices around our homes and workplaces. That way heat, moisture, and water are unable or less able to pass through them.

Why Silicone Sealants Have Low Heat Conductivity

If silicone can be so varied in its conductivity, how are silicone sealants so effective at resisting heat transfer across them? This has to do with some of the properties inherent to typical silicone materials. Because of how the elements in silicone (oxygen and silicon) behave at the molecular level, they’re not great conductors of heat.

Some elements, such as heat-conductive metals (like copper), allow the movement of free electrons between molecules. Oxygen and silicon, when bonded together in chains, do not. This means that heat must be transferred through them through vibration, which is far less effective than through the transfer of electrons.

This makes silicone a poor conductor and an effective insulator of heat by default. The exception is when it's created with additional elements that enable the effective transfer of heat through it.

Benefits of Insulative Silicone Sealant

In silicone sealants, insulative properties are usually ideal. They enable us to apply a flexible, lightweight, and strong material to homes and commercial buildings that can effectively block the transfer of moisture, heat, and air. This can be useful for making homes and businesses more energy efficient and better protected against potential water damage.

In addition to insulating from the outside, silicone sealant can be a great option for use indoors. Silicone sealant can often resist a high level of heat without deteriorating or breaking down. This makes some silicone sealants effective for use near extremely high heat spaces such as between an oven and adjacent parts of a home or business. Silicone sealant can also typically resist extremely low temperatures without freezing or cracking.

Finally, silicone sealants typically possess a high level of thermal stability and can tolerate extreme discrepancies of heat without shattering. In addition to these thermal properties, silicone can retain its flexibility across a wide range of temperatures. This contributes to its efficacy as an effective sealant in the long term — even as weather changes throughout the seasons.

Why Some Silicone Is Thermally Conductive

Silicone, without adding certain elements or materials, is generally a poor conductor of heat. This makes it an effective insulating material, but that isn’t ideal for all applications.

What about silicones that do transfer heat easily? What accounts for this discrepancy? Let’s explore.

We’ve discussed why silicone’s chemical structure makes it naturally effective at resisting the transfer of heat and how there are a number of applications for silicone materials in which they do effectively transfer heat. So, how do we reconcile these two concepts? This mainly has to do with additives that are put into silicone to facilitate the efficient transfer of heat.

For many applications, thermal conductive silicone is an ideal material — offering lightweight flexibility and strength in addition to its high thermal conductivity. But how is this achieved? In most cases, improved thermal conductivity is achieved through the addition of extra elements.

Silicone can be made with silicon, oxygen, and additives, such as thermally conductive materials. By adding these, we’re able to create silicone that is able to facilitate an efficient transfer of heat. For effective thermal management applications such as building computers, this can be an important asset of silicone materials.

The Bottom Line

Silicone is a fascinating range of materials. Silicone can possess a wide range of material properties, making it a highly versatile set of compounds. Among these varying material properties, its thermal conductivity can be one of the most notable. It varies widely and is often used in applications that necessitate near-opposite properties in terms of thermal conductivity.

Silicone made of only silicon and oxygen is a poor conductor of heat, making it an ideal material for home insulation. However, the addition of extra materials can make silicone an effective conductor of heat.

While silicone can possess a range of thermal properties, silicone sealants are generally designed to resist heat transfer effectively. This makes them ideal for sealing buildings off from moisture, air, and heat. Silicone sealants’ resistance to extreme temperatures also makes it an effective material to use for long-term sealing. It can resist fluctuations in temperature while retaining its efficacy as a sealant.

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Don’t forget — at Silicone Depot, we carry a range of silicone sealants designed to meet a wide range of use cases. Whether you’re looking for automotive silicone sealant, silicone sealant for use in homes and businesses, or sealing and caulking accessories, we’ve got you covered. Be sure to check out our range of silicone sealants today!