of butadiene and acrylonitrile are known by several
generic names, Buna N, Nitrile Rubber and NBR. The
acrylonitrile content of NBR compounds varies considerably
(18% to 50%) and influences the physical properties
of the finished material.
higher the acrylonitrile content, the better the resistance
to oil and fuel. At the same time, elasticity and
compression set resistance to low temperature is adversely
affected. The lower acrylonitrile content obtains,
the better low temperature resistance, but at a sacrifice
to some resistance to oils and fuels. In view of these
opposing realities, a compromise selection is the
medium acrylonitrile content rubber. NBR has good
mechanical properties when compared with other elastomers
and high wear resistance.
NBR is not resistant to weathering
and ozone. Some special compounding can improve this
defect by the use of a NBR/PVC blending compound which
has excellent weathering and ozone resistance and
good resistant to fuel but compression set is not
For NBR the service temperature can be designed from
-55 C to 100 C or up to 125 C depending on different
acrylonitrile content and formula. Generally higher
than 100 C, life time will be shortened.
40 to 90 Shore A are available.
brown, green, white, rust, yellow, blue, red, orange,
and gray are available, or any assigned color from
NBR compounds have excellent resistance to abrasion,
non-polar oils and solvent, water and permeation
(higher acrylonitrile content will be better). NBR
also can be used in conditions of dilute acids,
alkalis and salt solution at low temperatures. Applications
in aromatic hydrocarbons, chlorinated hydrocarbons
and polar solvents are not suitable.