Nitrile Rubber (NBR)

Material Description

Nitrile rubber (NBR), also known as Buna N, is one of the most commonly used sealing elastomers due to its resistance to petroleum-based fuels and lubricants and its relatively low price. Nitrile elastomers are copolymers of acrylonitrile and butadiene. There are a number of common variations of nitrile compounds.

Acrylonitrile Content

The acrylonitrile (ACN) content of the polymer chains can vary from 18% to 50%. Lower ACN content gives better low-temperature properties but inferior resistance to fuels and polar lubricants. Higher ACN content gives lesser quality low-temperature properties but improved fuels and polar lubricants resistance. Standard NBRs typically have 34% ACN content.

Cure system: Sulfur-cured

Standard Nitriles are usually sulfur-cured. Sulfur-cured compounds offer better low-temperature properties but are more prone to hardening with high temperatures. Peroxide-cured nitriles have better heat resistance and lower compression sets but are more expensive and more difficult to process.

Temperature Range:

Standard Low Temp: -40°C (-40°F)
Standard High Temp: 100°C (212°F)