NBR Testing Services

Polyhedron Laboratories performs testing on NBR raw material and products. Our lab offers a complete range of tests on any of the properties of NBR. In addition, Polyhedron tests can:

Perform quality assurance
Determine environmental aging and chemical resistance
Run product analysis to determine why a product or material did not meet failure requirements.

Polyhedron's tests meet ASTM testing standards.

NBR Information

NBR is a family of unsaturated copolymers of acrylonitrile and butadiene rubber. By varying the ratio of acrylonitrile content in the compound, the manufacturer can create a custom product to meet application requirements that require fuel, oil or chemical resistance. NBR products are used for fuel, oil and hydraulic hoses, seals, grommets, belting and roll covers in the automotive, plumbing and appliance industries.

There are five general types of NBR.

Cold NBR is polymerized at temperatures from 5° to 15°C, yielding more-linear polymer chains.
Hot NBR is manufactured at temperatures ranging from 30° to 40°C, which yields highly branched polymers. The branching supports a strong bond and improved hot tear strength compared to cold NBR. Hot NBR is excellent for compression molded products, extruded shapes and sponge products.
Crosslinked Hot NBR has an added di-functional monomer that provides the rubber with increased strength for molding and shape retention for extruded products. These NBR's are used as additives to PVC's to increase impact resistance and flexibility.
Carboxylated Nitrile (XNBR) is used when increased strength is required for an application. It is manufactured by the addition of carboxylic acid groups to the NBR polymers' backbone.
Bound Antioxidant NBR has antioxidants polymerized into the polymer chain. The addition of antioxidants protects the rubber during prolonged fluid exposure or in mixed fluid and air exposure in demanding environments.

The table below contains the key properties of NBR.

PROPERTIES	ASTM TEST METHOD	41% ACRYLONITRILE	21% ACRYLONITRILE
Density (g/cm³)	ASTM D 790		0.92
Tensile strength, psi	D412	3200	3055
% Elongation	D412	380	390
100% Modulus, psi	D412	300	355
300% Modulus, psi	D412	1750	2130
Tear Strength, Die C (lb/in)	D624		209
Hardness, Shore A	D2240	66	62
Glass Transition Temperature °C	D5026	-18	-60
Compression Set (%), 70 hrs./125°C	D395B	34	38
Brittleness Temperature °C	D746	-20	-45
Water Resistance (%), 70 hrs/ 23°C, % Volume Change	D471	+11	+5
Oil Resistance, 70 hr/ 100°C , % Volume Change	No. 3	-10	+49

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NBR Testing Services

NBR Information

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