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Nitrile Rubber. 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
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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)
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 • 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