There is a reason why industrial designers are so fond of elastomers. Combining the resilience of elastic and the insulating property of polymer, this material has a wide application in a number of scenarios. Chemically, elastomer or ‘elastic polymer’ is composed of long chainlike molecules. Stretch them, bend them or compress them, they are back to shape as soon as you remove the force. This pliability makes elastomer products a favorite as bearings and head gaskets in automotive engines, sealant in electromagnetic shielding applications, in hydraulic, pneumatic and O-Ring deployments, and more.
The Chemistry behind Elastomer
Under normal condition, long, chain-like molecules in elastomer are coiled together. The formation is not uniform though – they are rather arranged in random and irregular chains. As you apply force, these molecules start expanding, toward the direction of force. The way they stretch will remind you of those commonly used items – the rubber bands. Take out the force and the molecules spontaneously return to their normal arrangement. This unique property turns elastomer into one of the world’s most flexible materials. Natural rubber is a good example of industrial polymers. However, in recent times, many synthetic polymers such as styrene-butadiene and butadiene rubber have overtaken their natural sibling in popularity. These synthetic products are mostly derived from by-products of petroleum and natural gas.
Properties of Elastomer
Elasticity: It is precisely this property, which enables elastomer products to get back to shape after being expanded, compressed or bent by any kind of external force.
Resiliency: One of the most interesting aspects of elastomer is that the deformation lasts only as long as you apply the force. The moment the external force is withdrawn, the deformation gets repaired. However, when the material gets back to shape, not all of the energy that has been applied to the elastomer is returned. A part of it is dissipated as heat energy within the product. An elastomer material’s resilience is determined by the ratio of energy returned and energy applied.
Other Traits: In addition to high elasticity and resilience, elastomer products also boast of excellent electrical and thermal insulation. Thanks to their low permeability, elastomer products will scarcely allow gas, water or steam to flow through them. Above all, the materials show a number of excellent mechanical properties.
Elastomer versus Polymer
Not all polymer products possess high internal flexibility to be elastic and therefore extensible. Whether they will have these properties or not depends on their molecular structure. The polymers that look glassy in their physical appearance do not have high elasticity or resilience, and therefore are not elastomers. In addition, the products that crystallize at normal temperature are also not elastomers. Polymers that do not possess these qualities fall into the categories of plastics or resins. Those keen on using elastomer products for industrial applications should keep in mind that there are mainly four major types of elastomers: cis-polyisoprene (natural rubber), cis-polybutadiene (butadiene rubber), styrene-butadiene rubber, and ethylene-propylene monomer.
Elastomers are some of the most versatile materials available to the industrial designers. No wonder, elastomer products play a huge role in the world of engineering today. They find endless applications across the mechanical, electrical, automobile and other industries, where these flexible materials are used to accomplish a variety of design and performance-related goals. Elastomer products also play a vital role in addressing the growing issue of electromagnetic interference. Gaskets and seal applications are two of the areas where these products see some of the widest utilization. With a range of synthetic materials available today, it has become easier to produce tailor-made elastomer items to meet unique production conditions or application needs.