A wide choice of basic polymers (rubbers) is available, and many of these rubbers are compounded to obtain different properties. The comments below are limited to the basic elastomers.
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ASTM Designation |
Common Name | Composition | General Properties | Cloth Inserted | Diaphragm | Unsupported | ASHTO | ASTM D-2000 Mil Spec | Electrical Conductive |
| NR | Natural | Isoprene, Natural | Excellent physical properties including abrasion and temperature resistance. Poor resistance to petroleum-based fluids, ozone, sunlight |
X | X | X | X | X | |
| IR | Polyisoprene | Isoprene, Synthetic | Similar to natural rubber. More uniformity in light colors, i.e. Tan. Slightly less abrasion resistance | X | X | X | |||
| SBR | SBR | Styrene-Butadiene | Good physical properties and abrasion resistance. Poor resistance to petroleum based fluids. | X | X | X | |||
| CR | Neoprene | Chloroprene | Good weathering resistance. Flame retarding. Moderate resistance to petroleum-based fluids. Good multi-use physical properties. | X | X | X | X | X | X |
| NBR | Buna N | Nitrile-Butadiene | Excellent resistance to petroleum-based fluids. Good physical properties, i.e., moderate abrasion resistance, good temperature range, ozone resistance. | X | X | X | X | ||
| IIR | Butyl | Isobutene-Isoprene | Very good weathering resistance. Excellent dielectric properties. Low permeability to air. Good physical properties. Poor resistance to petroleum-based fluids. | X | X | X | X | ||
| EPDM | Ethylene-Propylene Rubber | Ethylene-Propylene-Diene Methylene | Excellent Ozone, chemical and propylene-diene-methylene aging resistance. Poor resistance to rubbers petroleum-based fluids. Excellent heat resistance. | X | X | X | X | ||
| EPT | Ethylene-Propylene | Ethylene Propylene Terpolymers | Excellent Ozone, chemical and propylene-diene-methylene aging resistance. Poor resistance to rubbers petroleum-based fluids. Excellent heat resistance. | X | X | X | X |