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 & Peroxide-Cured
Standard Nitrile o-rings are usually sulfur-cured. Sulfur-cured compounds offer better low-temperature properties but are more prone to hardening with high temperatures. Peroxide-cured nitrile o-rings have better heat resistance and lower compression sets but are more expensive and more difficult to process. Standard materials in stock include sulfur-cured 70 & 90 durometer (N70, N90) and peroxide-cured 90 durometer (N90PC).
Temperature Range (Typical Compounds)
Sulfur-Cured:
Standard Low Temp: -35°C (-31°F)
Standard High Temp: 120°C (248°F)
Peroxide-Cured:
Standard Low Temp: -29°C (-20°F)
Standard High Temp: 135°C (275°F)
Low-Temp Buna Nitrile O-Rings:
N70LT Low Temp: -55°C (-67°F)
N70LT High Temp: 100°C (212°F)