The Kadant Blog

Polymer Selection in Rubber Expansion Joints

Selecting the best suited polymer for your application is very important to the life expectancy and performance of rubber expansion joints. Kadant Unaflex offer a wide assortment of these polymers. Popular options include:

  • EPDM
  • Neoprene
  • Nitrile
  • SBR

Style3150 Wrapping SMWhy are these so popular? Let’s look closer at the properties of each.

EPDM (Ethylene-Propylene-Diene-Terpolymer) is a synthetic rubber used in a variety of applications. EPDM is compatible with alkalis, ketones, and water. EPDM however is not compatible with hydrocarbons including most petrochemicals such as gasoline, kerosene, and oils. EPDM features a good resistance to Ozone, heat steam, and weather making it a well-rounded selection for rubber expansion joints. EPDM is commonly used in power generation plants due to its resistance to radiation and high temperature compatibility.

Neoprene is a synthetic polymer produced by polymerization of chloroprene. Neoprene is widely used in water applications and handles weather and ozone very well. Neoprene has good resistance to dilute acids as well. 

Nitrile is synthetic rubber copolymer of acrylonitrile (ACN) and butadiene. Also known by names NBR, Perbunan®, and Nipol®. Nitrile is the most common option for gas, oil and other petrochemicals. Refineries, oil rigs, shipping vessels, and any petrochemical system would be an ideal host for Nitrile expansion joints.

SBR is derived from styrene and butadiene. SBR has good abrasion resistance making it a good candidate for slurries and other applications where abrasive material will be in contact with the expansion joint. SBR is generally a lower cost material in expansion joint production.

PTFE (polytetrafluoroethylene) is a durable non-stick material developed by DuPont in 1938. Kadant Unaflex uses PTFE in conjunction with its rubber expansion joints enhancing the durability and performance of the joints. PTFE has many non-stick and chemical resistance properties that greatly enhance the uses of the rubber polymers alone.

Aside from the four rubber polymers mentioned above, Kadant Unaflex offers many other options including, Viton®, gum rubber, butyl, and chlorobutyl to name a few. Many of our customers pre-select the rubber compound they require for their joints.

*Perbunan is a trademark owned by Arlanxeo. Nipol is a trademark owned by Zeon Chemicals L.P. Viton is a trademark owned by DuPont Performance Elastomers.

  • Written by:

    Jason Pruitt

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