Why Doesn’t Silicone Melt Or Burn – Here are the Secrets behind Silicone Heat & Temperature Resistance

Whether silicon burns or melts depends on the surrounding temperature conditions. As a matter of fact, silicone is one of the few rubber materials known to withstand high temperature.

In this guide, we will explore some intriguing thermal properties of silicone. From melting point, burning to flammability – the information will help you decide whether silicone is a perfect rubber for your application or not.

Silicone Rubber Temperature for Common Applications

Silicone Spoons
Silicone Spoons

Silicone rubber resists temperature excellently. This makes it ideal for various uses or applications. Below are some common uses to note:

  • General-purpose grades can be used in making O-rings, seals, tubing, gaskets, and more.
  • Low temperature is ideal in applications like aerospace, refrigeration equipment, and cryogenics.
  • High-temperature applications include industrial machines, automotive engine parts, heat resistant seals, etc.
  • High-tear strength applications include inflatable seals, molded components, and diaphragms.
  • Food-grade applications include bakeware, food-processing equipment, food storage container seals, cooking utensils, etc.
  • Electric conductive grade is used in conductive gaskets, electronic parts, and EMI/RFI.
  • Flame-retardant silicone rubber uses include safety equipment, electrical insulation, aerospace, etc.
  • Medical silicone rubber grade is used in seals, implants, medical devices, tubes, etc.
  • Oil-resistant grade is used in seals, industrial machine parts, and automotive gaskets.

Why Silicone Does not Burn

Ideally, silicone does not burn with ease because of its chemical structure and setup. It is made of Si (silicon) and O (oxygen) atoms. This combination is what forms its structure called polysiloxane. Due to this bond, silicone doesn’t burn with ease.

Silicone Rubber Structure
Silicone Rubber Structure

Why Silicone Does not Melt Easily

Probably, you are wondering why silicone rubber does not melt easily. Let’s look at some common reasons:

  • It is able to resist high heat temperature
  • Due to its cross-linked molecular structure
  • Because it has unique thermosetting properties
  • Comes with low glass transition temperature
  • High stability nature
  • High level of chemical inertness

Melting Temperature of Silicone in Degree Celsius

Silicone melting temperatures are mostly not the same. It differs based on the type of silicone and how it is formed.

Nonetheless, general-purpose types mostly have a melting point that ranges from 200 to 300 degrees Celsius. Melting points can, however, go higher based on the type of silicone and how high they are, up to 300 degrees Celsius or more.

Melting Temperature of Silicone in Fahrenheit

Silicone melting temperature in Fahrenheit will mostly range from 392°F to 572°F. This will vary based on the type of silicone and its formation method.

Thermal Properties of Silicone

Silicone is known for its unique thermal properties. These properties include:

High Resistance to Heat

Silicone can resist heat within a specific temperature range. During the safe temperature range, silicone maintain most desirable properties.

  • Thermal conductivity is low
  • High thermal stability levels
  • High flexibility no matter the range of temperature
  • Can experience changes in thermal expansion
  • Has excellent thermal insulation properties

Silicone Thermal Reaction at Auto Ignition Temperature

The behavior of silicone where its auto ignition temperatures are concerned is linked mostly to its thermal characteristics. Some info to note down include:

  • Temperature of auto ignition

At this temperature, material ignites spontaneously without external ignition sources like sparks or flame. Where silicone is concerned, auto ignition temperatures are quite high. It is mostly over 400°C.

  • Thermal decomposing

Before silicone gets to its temperature of auto ignition, it goes through thermal decomposition. This method entails the chemical breakdown of chemical bonds within silicone polymer chains because of its high temperature.

  • Mechanism of auto ignition

As temperature goes higher towards the auto ignition level, heat energy gathered is able to overcome activation energy needed for combustion. This leads to a strong ignition of vapors and gases released during the process of thermal decomposing, with oxygen presence available too.

Melting Temperature of Different Silicone Grades

Silicone melting temperature can differ based on the grades. Below are the different silicone grades:

  • All-purpose or general purpose grade

This grade melts mostly around 200°C to 300°C (392 to 572°F).

  • High temperature grade

High temperature silicone grades melt mostly above 300°C (572°F).

  • LSR or liquid silicone rubber grade

This grade of silicone does not come with unique melting points like those that solid silicone has. This is because of its nature of being liquid-like prior to curing.

  • Fluorosilicone grade

Its melting temperature is mostly around 200°C to 300°C (392 to 572°F).

FAQs

1. Does Silicone Melt in Boiling Water?

No, it doesn’t.

2. At what Temperature Does Silicone Melt?

It melts above 200°C or 392°F. This melting temperature will changed based on the type of silicone  being used.

3. Is Burning Silicone Toxic?

Yes, it is. When burnt, its smoke is not healthy to breathe in. This makes it toxic.

4. Does Silicone Burn in Oven?

No. This is because normal oven baking temperature is not hot enough to melt or burn silicone.

5. Does Burning Silicone Produce Gas?

Yes, it produces gas.

6. Is Silicone Flammable?

No, it isn’t flammable.

7. What Happens if you Burn Silicone?

If silicone is burnt, it first decomposes. Then, it gives up fumes like carbon dioxide, silicone dioxide, and some other harmful minute compounds. Silicone itself when is burnt chars and loses its integrity structurally.

Conclusion

Ideally, silicone has a high working temperature than most rubber materials available in the market. For this reason, silicone does not readily melt or burn when subjected to high temperature.

At LEGENDAY, we manufacture a range of silicone products designed for a range of applications. For any inquiries about silicone products, contact us now.

 

More resources:

Temperature and Silicone – Source: LEGENDAY

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