Nitrile Rubber, also known as NBR, Buna-N, and Acrylonitrile Butadiene Rubber, is a Synthetic Rubber Copolymer of Acrylonitrile (ACN) and Butadiene. Trade names include Perbunan, Nipol, Krynac and Europe.

Nitrile Butadiene Rubber (NBR) is a family of unsaturated copolymers of 2-Propenitrile and various butadiene monomers (1,2-Butadiene and 1,3-Butadiene). Although its physical and chemical properties vary depending on the composition of the polymer Nitrile, this form of synthetic rubber is unusual in that it is generally resistant to oil, fuel, and other chemicals (the more nitrile in the polymer, the higher the resistance to oils, but the lower the flexibility of the material).