Difference Between Rubber and Silicone

The key difference between rubber and silicone is that the backbones of most of the rubber forms contain carbon-carbon bonds while the backbone of silicone contains silicon and oxygen.

Both rubber and silicone are elastomers. They are polymeric materials that exhibit the viscoelastic behaviour, which we generally call as elasticity. We can distinguish silicone from rubbers by the atomic structure. In addition, silicones have more special properties than normal rubbers. Rubbers are naturally occurring, or else we can synthesize them, but silicon is only synthetic in nature. Depending on these, we can find the difference between silicone and rubber.

CONTENTS

1. Overview and Key Difference
2. What is Rubber
3. What is Silicone
4. Side by Side Comparison – Rubber vs Silicone in Tabular Form
5. Summary

What is Rubber?

Generally, we consider all the elastomers as rubbers in which dimensions undergo alterations largely by stressing, and also they can go to the original dimensions after removing the stress. These materials show glass transition temperature due to their amorphous structure. There are many types of rubbers or elastomers like natural rubber, synthetic polyisoprene, styrene butadiene rubber, nitrile rubber, polychloroprene, and silicone.

However, natural rubber is the rubber that comes to our mind when considering rubbers. We get the natural rubber from the latex of rubber tree (Heveabrasiliensis). Also, cis-1, 4-polyisoprene is the structure of natural rubber. Even though silicone rubbers contain silicon in polymer chains instead of carbon, most of the rubbers contain polymer chains of carbon.

Figure 01: A Natural Rubber Sheet

In addition to that, rubber is useful for many applications like cookware, electronics, automotive applications etc., because of their elastic behaviour. As they are waterproof materials, they are useful as sealants, gloves etc. Rubbers or elastomers are excellent materials for insulating purposes.

What is Silicone?

Silicone is a form of synthetic rubber. We can synthesize it by modifying silicon. Furthermore, this material consists of a backbone of silicon atoms with alternating oxygen atoms. As silicone has high energy silicon-oxygen bonds, it is more resistant to heat than other rubbers or elastomers.

Unlike in other elastomers, the inorganic backbone of silicone makes it highly resistant to fungus and chemicals. In addition, silicone rubber is resistant to ozone and UV attacks because the silicon-oxygen bond is less susceptible to these attacks than the carbon-carbon bond of the backbone in other elastomers. Moreover, this material has a lower tensile strength and lower tear strength than the organic rubbers. However, at high temperatures, it shows excellent tensile and tears properties. This is because of the variation of properties in silicone is less at high temperatures.

Figure 02: Mats made of Silicone

Silicone is more durable than other elastomers. These are few of the beneficial properties of silicone. Regardless, the fatigue life of silicone rubbers is shorter than the organic rubbers. It is one of the disadvantages of this rubber form. Also, its viscosity is high; therefore, it causes manufacturing problems due to poor flow properties.

What is the Difference Between Rubber and Silicone?

Silicone is a form of synthetic rubber. However, the key difference between rubber and silicone is that the backbone of silicone contains silicon and oxygen, while the backbones of most of the rubber forms contain carbon-carbon bonds.

Moreover, concerning the properties, the difference between rubber and silicone is that the normal rubber is usually less resistant to heat, chemical attacks, fungus attacks, UV and Ozone attacks. But, silicone is more resistant to heat, chemical attacks, fungus attacks, UV and Ozone attacks than normal rubber.

Furthermore, as another significant difference between rubber and silicone, organic rubbers have poor tensile and tear properties at high temperatures while these properties are excellent in silicone rubbers at the same temperature conditions. Therefore, silicone rubber offers special properties, which organic rubbers do not possess.

Summary – Rubber vs Silicone

Silicone is a form of synthetic rubber. Therefore, it also is a type of elastomer as rubber. The key difference between rubber and silicone is that the backbones of most of the rubber forms contain carbon-carbon bonds while the backbone of silicone contains silicon and oxygen.

Reference:

1. Britannica, The Editors of Encyclopaedia. “Silicone.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 19 Jan. 2016. Available here 
2. Lazonby, John. “Silicones.” The Essential Chemical Industry Online. Available here 

Image Courtesy:

1.”Natural rubber drying 1″By Slashme – Own work, (CC BY-SA 4.0) via Commons Wikimedia
2.”2359484″ (CC0) via Max Pixel

ncG1vNJzZmivp6x7pbXFn5yrnZ6YsqOx07CcnqZemLyue8OinZ%2Bdopq7pLGMm5ytr5Wau26%2B1JuZnqpdlruledWsZKyhnJ6wsLrEaA%3D%3D