We use cookies to enhance your experience. By continuing to browse this site you agree to our use of cookies. More info.

The rubber materials selected by designers and technical buyers should meet all their application requirements. The inherent physical characteristics of elastomers can be modified through compounding. However, the knowledge of rubber’s physical properties and their measurement is critical for compound selection.

The following are the physical properties of rubber:

The article explains these properties of rubber in detail.

The chemical structure of the elastomers provides them with an inherent hardness that can be altered. The modified hardness is then measured in terms of of durometer (duro) on a Shore scale. Shore A is used for a soft to medium-hard rubber. Solid rubber, with a consistency of pencil erasers, has a hardness of 40 duro. By contrast, harder rubber, like that used in hockey pucks, has 90 duro hardness. Figure 1 shows rubber with different hardness.

Figure 1. Rubber with different hardness

Tensile strength is the amount of force needed to tear apart a rubber specimen until it breaks. It is also known as ultimate tensile strength, and is measured in terms of megapascals or pounds per square inch (psi) according to ASTM D412. The tensile strength is a key factor for designers and buyers as it signifies the point of failure resulting from the stretching of rubber.

Tensile modulus is the stress or force required for producing a strain or an elongation percentage in a rubber sample. Although it sounds similar to tensile strength, the properties are different. Harder rubber usually has a higher tensile modulus, making it more resilient. It is also more resistant to extrusion, which is a process for manufacturing stock materials used in custom fabrication.

Elongation is defined as the percentage increase, or strain, in the original length of a rubber sample with the application of a tensile force, or stress. Certain elastomers tend to stretch more compared to others. Natural rubber, for instance, can stretch up to 700% prior to reaching its ultimate elongation, which causes it to break. However, fluoroelastomers can only withstand 300% elongation.

Resilience, also known as rebound, is the ability of rubber to return to its original size and shape following a temporary deformation, such as contact with a metal surface. Resilience is critical in dynamic seals that serve as a barrier between stationary and moving surfaces. It is necessary to take into account resilience for applications that require weatherstripping between a door frame and a door.

Compression set is the extent to which an elastomer fails to return to its original thickness upon releasing a compressive load. Repeated compression of a rubber seal over time results in progressive stress relaxation. Compression set is the end result of a continuous decline in sealing force. Figure 2 shows the schematic of compression set.

Tear resistance is the resistance of an elastomer to the development of a cut or nick when tension is applied. This property, also called tear strength, is measured in kilonewtons per meter (kN/m) or pound force per inch (lbf/in). It has to be considered when selecting a compound for edge trim that will be in contact with sharp objects or rough metal edges.

Abrasion resistance is the resistance of rubber to abrasion by scraping or rubbing. Abrasion-resistant rubber is used in industrial applications including conveyor belts that move coal, and pumps that handle slurries. The measurement of material loss due to abrasion is carried out according to tests such as ASTM D394.

Specific gravity is the ratio of a material's weight to the weight of an equal volume of water at a particular temperature. This property enables the chemists to identify compounds. It is important for part designers and technical buyers to be aware that rubber with a low specific gravity provides more square inches per pound of stock. By contrast, those with a higher specific gravity have advantages in molding consistency.

Elasto Proxy has been the worldwide manufacturer of custom-fabricated specialty seals and custom insulation for more than 25 years. They serve different industries including automotive and mobile specialty vehicles.

This information has been sourced, reviewed and adapted from materials provided by Elasto Proxy.

For more information on this source, please visit Elasto Proxy.

Please use one of the following formats to cite this article in your essay, paper or report:

Elasto Proxy, Inc.. (2019, July 18). Physical Properties of Rubber – a Buyer and Designer’s Guide. AZoM. Retrieved on May 28, 2022 from https://www.azom.com/article.aspx?ArticleID=11914.

Elasto Proxy, Inc.. "Physical Properties of Rubber – a Buyer and Designer’s Guide". AZoM. 28 May 2022. <https://www.azom.com/article.aspx?ArticleID=11914>.

Elasto Proxy, Inc.. "Physical Properties of Rubber – a Buyer and Designer’s Guide". AZoM. https://www.azom.com/article.aspx?ArticleID=11914. (accessed May 28, 2022).

Elasto Proxy, Inc.. 2019. Physical Properties of Rubber – a Buyer and Designer’s Guide. AZoM, viewed 28 May 2022, https://www.azom.com/article.aspx?ArticleID=11914.

Do you have a review, update or anything you would like to add to this article?

In this interview, AZoM talks to Chris Aylott, Senior Engineer at Newcastle University, about fatigue testing in the development of low carbon transport solutions.

AZoM speaks with Dr. Nicola Ferralis from MIT about his research that has developed a low-cost process of creating carbon fibers from hydrocarbon pitch. This research could lead to the large-scale use of carbon fiber composites in industries that have thus far been limited.

In this interview, AZoM speaks with Marco Enger, Senior Tribologist from GGB, to discuss how nano fillers affect transfer films within tribological systems.

This product profile outlines the Versa Flex Checkweighers from Thermo Fisher Scientific.

The LQA 300 FT-IR wine analyzer combines performance, accuracy, ease-of-use, and speed for the analysis of finished wine, must and must under fermentation samples in less than 45 seconds—all in one compact solution.

The SpectraStar™ XT-R Benchtop NIR can analyze virtually any sample type in less than a minute, including solid, slurry, or liquid samples.

This article provides an end-of-life assessment of lithium-ion batteries, focusing on the recycling of an ever-growing amount of spent Li-Ion batteries in order to work toward a sustainable and circular approach to battery use and reuse.

Corrosion is the degradation of an alloy caused by its exposure to the environment. Corrosion deterioration of metallic alloys exposed to the atmosphere or other adverse conditions is prevented using a variety of techniques.

Due to the ever-increasing demand for energy, the demand for nuclear fuel has also increased, which has further created a significant increase in the requirement for post-irradiation examination (PIE) techniques.

AZoM.com - An AZoNetwork Site

Owned and operated by AZoNetwork, © 2000-2022