Elastomers and Rubbers - Is There a Difference?

Elastomers and rubbers are handy because of their unique material properties

Exploded cross section and exploded views of a diaphragm check valve showing the elastomeric diaphragm free floating disc.Rubber and elastomer are words commonly used to mean any material with rubber-like properties. Elastomer is shorthand for elastic polymer. Elastomers are viscoelastic: sticky, very elastic polymers (plastics). Natural rubber is an elastomer made from latex, a milky tree sap. Synthetic elastomers are made from petroleum. Rubber is frequently used to indicate elastomers that must be vulcanized or cured to be useful.

What are elastomers and rubbers?
Elastomers are best described as rubbery materials. Rubber originally meant natural rubber. Later on, elastomer became the word used to talk about synthetic rubbers. Most rubbery materials are now considered a type of elastomeric material.

Elastomers are useful
Liquid and gas handling systems require flexible, durable and reliable seals. Elastomers are perfectly suited for this type of use. Elastomers improve system service life by making them more reliable. They also reduce maintenance costs.

Elastomers are flexible
Manufacturers are able to mold elastomers into all kinds of shapes. Elastomers are bendable and twistable at room temperature. They are also very heat resistant. Their mechanical properties and overall good chemical resistance make them very useful.

An exploded view of an ISM modular check valve. Click here to go to a landing page where you can get more information about these valves.

Modular Check Valves

We've taken spring-loaded check valves to a whole new level. Mix and match imperial and metric connections. Watch the video.

A play button for a video about ISM's modular check valves. Click here to go to a landing page where you can watch the video.

The Elastomers Chemical Compatibility Chart from ISM can help with elastomer choice.

Some physical properties of elastomers and rubbers

  • Permeability - Elastomers generally resist the passage of air, gasses, steam, water and fluids.
  • Tackiness - Elastomers resist sliding on most other materials. This includes various fibers, metals and rigid plastics.
  • Insulation - Elastomers tend to be good electrical insulators. They are also good insulators to heat and cold.

Elastomers and rubbers have good mechanical properties that make them flexible but tough

  • Good resistance to breaking when stretched
  • Elastic
  • Tear resistant
  • Abrasion resistant

The duckbills and diaphragms of plastic diaphragm check valves are made of elastomers. O-rings and gasket seals are too. This is because of the unique physical and chemical properties of elastomers. Most design processes can benefit from a better understanding of elastomeric materials. As always, ISM offers samples to our customers as a way to assist their testing and decision-making. These can be requested when browsing our catalog.

A related ISM blog post
      Elastomers Chemical Compatibility Chart, a New Resource

Some additional resources

  • Elastomers from the Polymer Properties Database
  • Elastomers from the Polymer Science Learning Center
    The Department of Polymer Science, University of Southern Mississippi
  • Vulcanization from Wikipedia

Has the selection of specialty elastomers and rubbers complicated choosing the best check valve for an application? What elastomeric properties were the most or least critical? Help us by telling others what you learned.

Have any questions about elastomers and their use in flow control components? If so, send me an email - steven.williams@industrialspec.com. You can also ask questions using the comments section below.


Steven C. Williams headshot March, 2018.

About the author
Steven C. Williams my LinkedIn profile link button.
Steven C. Williams, BS, is the technical writer and an inbound marketing specialist at Industrial Specialties Manufacturing (ISM), an ISO 9001-2015 supplier of miniature pneumatic, vacuum and fluid circuitry components to OEM's and distributors all over the world. He writes on technical topics related to miniature pneumatic and fluidic components as well as topics of general interest at ISM.       

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