Nitrile Rubber NBR, Buna-N

Carbonated nitrile rubber (XNBR) incorporates up to 10% of a third comonomer with organic acid functionality. When compared to NBR, XNBR has improved abrasion resistance and strength. XNBR can be difficult to process, and it requires special formulation to prevent sticking to mixer surfaces and premature vulcanization. 

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Table 4.18 Physical and Mechanical Properties of Nitrile Rubber (NBR, Buna-N)=>...

Nitrile rubber is also known as nihile-butadiene rubber (NBR), government rubber nitrile (GRN), and Buna N. 

Nitrile rubber (NBR) was first commercialized by I.G. Farbindustry, Germany, in 1937, under the trade name of Buna N. Its excellent balance of properties confers it an important position in the elastomer series. Nitrile rubber, a copolymer of butadiene and acrylonitrile, is widely used as an oil-resistant rubber. The acrylonitrile content decides the ultimate properties of the elastomer. In spite of possessing a favorable combination of physical properties, there has been a continuous demand to improve the aging resistance of NBR due to the tougher requirements of industrial and automotive applications. 

Acrylonitrile-butadiene rubber (also called nitrile or nitrile butadiene rubber) was commercially available in 1936 under the name Buna-N. It was obtained by emulsion polymerization of acrylonitrile and butadiene. During World War II, NBR was used to replace natural rubber. After World War II, NBR was still used due to its excellent properties, such as high oil and plasticizer resistance, excellent heat resistance, good adhesion to metallic substrates, and good compatibility with several compounding ingredients. 

The name originally applied to all synthetic rubbers produced by the sodium polymerisation of butadiene it is derived from Bu for butadiene and Na for sodium. The name was subsequently used in various forms, e.g., Buna N for nitrile rubber or NBR, and Buna S for SBR. The tradename Perbunan (Bayer) is also derived from Buna. 

Nitrile rubber - Copolymers of acrylonitrile and butadiene. Same as NBR or Buna-N. 

Copolymerization of butadiene with acrylonitrile is, like that of styrene, also carried out in emulsion. This may be a discontinuous copolymerization by the cascade process or it may be continuous with withdrawal of the latex from the bottom of the reaction pot. Acrylonitrile and butadiene are used in the azeotropic ratio of 37 63. The copolymers are commercially available under the name of nitrile rubber, or the initials NBR, previously also Buna N or GR-N. They are oil-resistant elastomers. Latices produced with cation-active emulsifiers are used to coat or impregnate textiles and paper. 

Acrylonitrile-butadiene copolymer Nitrile rubber. Buna N NBR... 

The physical and mechanical properties of the nitrile rubbers are very similar to those of natural rubber. Buna-N does not have exceptional heat resistance. It has a maximum operating temperature of 200°F/93°C and has a tendency to harden at elevated temperatures. The nitrile rubbers will support combustion and burn. NBR has good abrasion resistance and tensile strength. 

Other Names Natural (or Synthetic) Rubber NR (IR) BR Cis 4 Buna S Styrene SBR, GR-S Nitrile, Buna N Hycar NBR, GR-A... 

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