Both rubber and silicone are elastomers. They are polymeric materials that exhibit the viscoelastic behavior, which is generally called elasticity. Silicone can be distinguished from rubbers by the atomic structure. In addition, silicones have more special properties than normal rubbers. Rubbers are naturally occurring, or they can be synthesized. Based on this, silicone can be differentiated from rubber.
Generally, all the elastomers are considered as rubbers in which dimensions can be changed largely by stressing, and can be returned to the original dimensions after removing the stress. These materials show a glass transition temperature due to their amorphous structure. There are many types of rubbers or elastomers like natural rubber, synthetic poly isoprene, styrene butadiene rubber, nitrile rubber, polychloprene, and silicone. But natural rubber is the rubber which comes to our mind when considering rubbers. Natural rubber is obtained from the latex of Heveabrasiliensis. Cis-1, 4-polyisoprene is the structure of natural rubber. Most of the rubbers contain polymer chains of carbon. However, silicone rubbers contain silicon in polymer chains instead of carbon.
Silicone is a synthetic rubber. It is synthesized by modifying silicon. Silicone 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 its resistance to fungus and chemicals higher. 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. Silicone has a lower tensile strength and lower tear strength than the organic rubbers. However at high temperatures, it shows excellent tensile and tear properties. This is because the variation of properties in silicone is less at high temperatures. 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 silicone rubber. In addition, its viscosity is high; therefore, it causes manufacturing problems due to poor flow properties.
Rubber is used for many applications like cookware, electronics, automotive applications etc, because of their elastic behavior. As they are waterproof materials, they are used as sealants, gloves etc. Rubbers or elastomers are excellent materials for insulating purposes.
From all the rubbers, silicone is much better for thermal insulation due to its heat resistance. Silicone rubber offers special properties, which organic rubbers do not posses.