1. Nitrile Rubber
By:
Jessica M. Lopez

2. Nitrile Rubber
Polymeric mixture of butadiene and acrylonitrile in the respective ratio 2:1.
Ratios can be varied to change physical properties...higher levels of acrylonitrile yield low temperature flexibility, and increase compound hardness
Highly polar elastomer (large and reversible elsatic deformation)

3. Physical Properties Excellent Good Fair Poor Tensile strength •
Excellent
Good
Fair
Poor
Tensile strength •
Elongation
Low temperature flexibility
Compression Set
Tear resistance
Abrasion resistance
Flame resistance
Gas permeability

4. Chemical Resistance Excellent Good Fair Poor Water • Petroleum oil
Excellent
Good
Fair
Poor
Water •
Petroleum oil
Silicone lubricants
Dilute acids
Dilute alkalis
Hydraulic fluids
Transmission fluid
Steam
Ozone
Weather
Ketones
Strong acids
Brake fluid

5. Uses Vibration Control of horizontal forces up to 125 tons
O Rings, gaskets, sealants, grommets and tubing pads
Frequently used in automotive air conditioning systems employing R-134a refrigerants

6. Environmental Deficiencies
Nitrile should not be exposed to
direct sunlight
moderate to high levels of atmospheric ozone
oxygen
Must be used in a closed system

7. How to overcome
Nitrile accepts antidegradants, which improve the aforementioned properties
PVC (polyvinyl chloride)
Hydrogenation

8. Hydrogenated Nitrile Rubber
High tensile strength
Low permanent set
Good abrasion resistance
High elasticity
Stability toward thermal ageing
Better properties at low temperatures

9. How It’s Made
Nitrile rubber is hydrogenated in solution using precious metal catalysts
Carbon-carbon bonds are converted to more stable single bonds (controls different states)
Can be crosslinked using sulphur and peroxide cure systems

10. Cost Estimations Nitrile 1/32” thick $14.80 per square yard
Hydrogenated Nitrile
2 to 3 times more expensive than the conventional polychloroprene used now
New features will allow it to last 5.5 times longer

11. References
ATAS International B.V note/TECHNNO_23.pdf
R.T. Enterprizes
Callister, William D, Materials Science, An Introduction 6E, John Wiley & Sons, Inc, 2003
American Rubber Group