Nitrile Rubber

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Nitrile Rubber

• By
• Jessica M. Lopez
• MEEN 3344

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Nitrile Rubber

• Polymeric mixture of butadiene and acrylonitrile
  in the respective ratio 21.
• 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)

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Physical Properties
  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      
Silicone lubricants      
Dilute acids      
Dilute alkalis      
Hydraulic fluids      
Transmission fluid      
Steam      
Ozone      
Weather      
Ketones      
Strong acids      
Brake fluid      
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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

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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

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How to overcome

• Nitrile accepts antidegradants, which improve the
  aforementioned properties
• PVC (polyvinyl chloride)
• Hydrogenation

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Hydrogenated Nitrile Rubber

• High tensile strength
• Low permanent set
• Good abrasion resistance
• High elasticity
• Stability toward thermal ageing
• Better properties at low temperatures

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How Its 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

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Cost Estimations

• Nitrile
• 1/32 thick 14.80 per square yard
• ¼ thick 72.20 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

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References

• ATAS International B.V http//www.atas-int.com/ap-
  note/TECHNNO_23.pdf
• R.T. Enterprizes http//www.rtenterprises.com/comp
  _nitrile.htm
• Callister, William D, Materials Science, An
  Introduction 6E, John Wiley Sons, Inc, 2003
• American Rubber Group http//www.americanrubbergro
  up.com/