Nitrile Rubber By: Jessica M. Lopez

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)

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

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

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

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

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

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

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

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

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.americanrubbergroup.com/