Is Silicone a Rubber, Elastomer, or Polymer?

Silicone is a multifaceted polymer material that is made up of recurring subunits referred to as siloxane. These subunits consist of organic groups such as carbon and hydrogen, silicon, and oxygen. It is a synthesized variation of rubber.

What is Rubber?

This is a versatile elastic polymer that consists of two main variations; natural and synthetic rubber. The natural variation is derived from the sappy latex of specific trees with the most common one being Heveabrasiliensis. Its synthetic alternative is typically derived from petroleum products for example polybutadiene, silicone, and neoprene.

Molecular Structure of Natural Rubber
Molecular Structure of Natural Rubber

What is Elastomer?

These are elastic and highly durable materials that consist of long polymer chains that are bound together by fragile intermolecular forces. The weak forces give the material the ability to stretch and bend out of shape when subjected to stress. However, once the stress is removed the material typically reverts to its original shape.

There are various types of elastomers including natural rubber, synthetic rubbers, and thermoplastic elastomers. These elastomers can be utilized in a wide range of applications.

Chemical Structure of Elastomer
Chemical Structure of Elastomer

What is Polymer?

A polymer is a material that is composed of relatively large molecules referred to as macromolecules. These macromolecules contain recurring subunits called monomers. These subdivided units are joined together through chemical reactions which produce the long chain.

Chemical Reaction for Polymer
Chemical Reaction for Polymer

Silicone Rubber Properties

There are different variations of this material that have a different composition that makes them better suited for specific applications. You should take into account these properties as they help you determine the best variation for your application. Some of the most common properties of this material include the following;

Silicone Rubber Temperature Range

The average temperature of silicone material is relatively wide making it ideal for a wide range of applications. Its limit for high-temperature ranges between 200°C to 230°C which is the equivalent of 400°F to 450°F. Its limit for reduced temperatures is -54°C to -73°C the equivalent of -65°F to -100°F.

It is important to note that this material does not have a true melting point as it instead begins to lose its elasticity and other desirable physical properties at these temperatures. The material can ignite when exposed to a temperature of 450°C.

Silicone Rubber Structure

This polymer contains atoms of silicon, organic compounds, carbon, hydrogen, and oxygen. Silicon and oxygen are the primary components of this material with the organic compounds located on the silicon atoms.

This unique structure of siliconeis what gives the material all the elevated qualities such as enhanced stability and flexibility that allow it to remain functional even under extreme temperatures.

Resistance to Environmental Conditions

Aside from its elevated resistance to extreme temperatures silicone rubber has enhanced resistance to UV rays, moisture, ozone, and steam. This makes it viable even for outdoor applications which increase its range of applications making it truly versatile.

Flammability

The material has a very high tolerance to high temperatures with an impressive limit ranging from 200 °C to 230°C. This means that the material has very low flammability and only ignites at an extreme temperature of 450 degrees. Ideally, silicone is UL94v-0 rated, which is critical when choosing these materials for specific applications.

Toxicity

Silicone rubber is not toxic and does not react to food or beverages and also does not produce dangerous fumes which makes it relatively safe. However, the minute particles that it is composed of may pass through the skin which can lead to a build-up of toxins which is why you should use protective gear when handling it.

In fact, FDA approved silicone materials are a perfect choice for medical and food industries.

Chemical Inertness

This material has elevated resistance against the corrosive effects of chemical compounds, solvents, and fuels. Its resistance however is limited to mild compounds and it will therefore be affected by polar solvents, concentrated acids, and alkalis.

Electrical Properties

The material functions as a great electrical insulator making it ideal for electrical applications. Its insulating properties remain even under harsh conditions. You can modify it to be conductive by introducing fillers.

Properties for Silicone Rubber
Properties for Silicone Rubber

Silicone Rubber Classification

There are different types of categorization of silicone rubber. These categorizations are typically based on the composition and the structure of the silicone rubber in question. They include;

Classification based on Organic Groups

Under this category there are;

  • Methyl Group
  • Methyl and Phenyl Groups
  • Methyl and Vinyl Groups
  • Methyl, Phenyl, and Vinyl Groups
  • Fluoro, Vinyl and Methyl Groups

Classification Based on Molecular Structure

As per its molecular structure, silicone rubber can be classified into the following groups

Classification Based on Specific Properties

Under this category we have the following;

  • General Purpose
  • High Tear Resistant LSR
  • Heat Stabilized LSR
  • Coolant Resistant LSR
  • Self-Lubricating LSR
  • Flame Retardant LSR

Modification done to any of the categories listed above can be done to better adapt the material to its intended functions.

Uses of Silicone Rubber Material

Given its superior properties, this material is incredibly versatile and is often used as a multipurpose material for various applications. There is a multitude of applications from different industries ranging from domestic to industrial that utilize silicone rubber. You can use silicone rubber for the following;

  • Electronics Industry to insulating materials, EMI shielding, and grounding.
  • Food and Beverage Industry for processing components such as tubing, seals, hoses, and gaskets.
  • Medical Industry for medical implants and surgical tools given that it is resistant to the growth of bacteria.
  • Construction Industry for a wide array of applications such as O-rings, adhesives, gaskets, and sealants.
  • Aerospace and Automotive industry for designing parts such as vibration-dampening components, coatings, gaskets, and seals.
  • Consumer Products such as jewelry, toys, bakeware, utensils, and cookware.

FAQs

Is Silicone Rubber or Plastic?

Silicone displays properties that are linked to both rubber and plastic and as such can be referred to as a hybrid of the two materials. The material is synthesized and contains silicon, oxygen, carbon, and hydrogen.

Conclusion

Silicone rubber has many superior properties including its durability and elasticity which you to utilize in a wide range of applications in various industries. It is highly tolerant to extreme temperatures and has chemical resistance and good electrical properties allowing you to use it in multiple applications.

 

More resources:

Silicone vs Polycarbonate – Source: LEGENDAY

Is Silicone Toxic – Source: LEGENDAY

TPU vs Silicone – Source: LEGENDAY

EPDM vs. Silicone – Source: LEGENDAY

17 Silicone Elastomer Applications for Electronic Devices in Modern Industry – Source: Legenday

Update cookies preferences
Scroll to Top