General Characteristics of Common Polymers
Buna-N | Neoprene | ||
Common Names | Buna-N, Nitrile, NBR | Neoprene® | |
ASTM D-2000 Classification | BF, BG, BK | BC, BE | |
Military (MIL STD 417) | SB | SC | |
Chemical Definition | Butadiene Acrylonitrile | Polychloroprene | |
General Characteristics | |||
Durometer Range (Shore A) | 20 - 95 | 20 - 95 | |
Tensile Range (P.S.I.) | 200 - 3000 | 500 - 3000 | |
Elongation (Max %) | 600 | 600 | |
Compression Set | Good | Good | |
Resilience - Rebound | Good | Excellent | |
Abrasion Resistance | Excellent | Excellent | |
Tear Resistance | Good | Good | |
Solvent Resistance | Good to Excellent | Fair | |
Oil Resistance | Good to Excellent | Fair | |
Low Temperature Usage (F°) | +30° to -40° | +10° to -50° | |
High Temperature Usage (F°) | to 250° | to 250° | |
Aging Weather - Sunlight | Poor | Good | |
Adhesion to Metals | Good to Excellent | Good to Excellent | |
Comment |
Nitrile (Buna-N) is a general purpose oil resistant polymer which has good solvent, oil, water and hydraulic fluid resistance, good compression set, abrasion resistance and tensile strength. Nitrile should not be used in highly polar solvents such as acetone and MEK, ozone, chlorinated hydrocarbons and nitro hydrocarbons. |
Neoprene is an all purpose polymer with many desirable characteristics. It has additional plus features: high resilience with low compression set; flame resistant; compounds free of sulfur are easily made; and animal and vegetable oil resistant generally not affected by moderate chemicals, fats, greases and many oils and solvents. Neoprene is generally attacked by strong oxidizing acids, esters, ketones, chlorinated aromatic and nitro hydrocarbons. |
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Silicone | ||
Common Names |
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Silicone | |
ASTM D-2000 Classification | CA | FC, FE, GE | |
Military (MIL STD 417) | RS | TA | |
Chemical Definition |
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Polysiloxane | |
General Characteristics | |||
Durometer Range (Shore A) | 30 - 90 | 30 -90 | |
Tensile Range (P.S.I.) | 500 -3000 | 200 - 1500 | |
Elongation (Max %) | 600 | 700 | |
Compression Set | Good | Good | |
Resilience - Rebound | Good | Good | |
Abrasion Resistance | Good | Fair to Poor | |
Tear Resistance | Fair | Poor | |
Solvent Resistance | Poor | Poor | |
Oil Resistance | Poor | Fair to Poor | |
Low Temperature Usage (F°) | -20° to -60° | -60° to -150° | |
High Temperature Usage (F°) | to 350° | to 450° | |
Aging Weather - Sunlight | Excellent | Excellent | |
Adhesion to Metals | Fair to Good | Good | |
Comment |
Ethylene Propylene is a polymer with outstanding properties. It has exceptionally good weather aging and ozone resistance; excellent water and chemical resistance; excellent resistance to gas permeability and excellent resistance to aging due to exposure to steam; and heat resistance excellent up to 350°F. Ethylene Propylene is a polymer where oil and solvent resistance is poor, however, it is fairly good in ketones and alcohols. Ethylene Propylene is not recommended for food applications or exposure to aromatic hydrcarbons. |
Silicone Rubber has a great many variations and can be compounded to meet any number of applications. Silicone can be compounded to have tensile in the area of 1500 PSI and tear upto 200 lbs.; low compression set and good resilience; moderate solvent resistance; excellent heat resistance; good release characteristics; extreme low temperature properties; and can be highly resistant to oxidation and ozone attack Silicone is generally attacked by most concentrated solvents, oils, concentrated acids and dilute sodium hyrdoxide.. |
Fluorosilicone | Fluoro Elastomers | |
Common Names | Fluorosilicone | Fluoro Elastomers |
ASTM D-2000 Classification | FK | HK |
Military (MIL STD 417) | MIL-R-25988, Ammend. 2 | MIL-R-25897 and MIL-R-83248 |
Chemical Definition | Fluorosilicone | Fluorinated Hydrocarbon |
General Characteristics | ||
Durometer Range (Shore A) | 50 - 80 | 60 - 90 |
Tensile Range (P.S.I.) | 500 - 800 | 500 - 2000 |
Elongation (Max %) | 300 | 300 |
Compression Set | Good | Good |
Resilience - Rebound | Excellent | Fair |
Abrasion Resistance | Poor | Good |
Tear Resistance | Poor | Good |
Solvent Resistance | Fair | Excellent |
Oil Resistance | Good | Excellent |
Low Temperature Usage (F°) | -80° | +10° to -10° |
High Temperature Usage (F°) | 300° | 400° to 600° depending on time and service condition |
Aging Weather - Sunlight | Excellent | Excellent |
Adhesion to Metals | Poor | Good |
Comment |
Fluorosilicone is considerably more expensive than silicone, however it is developed for special applications where general resistance to oxidizing chemical, aromatic and chlorinated solvent bases is required. Fluorosilicone is not recommended and is generally attacked when exposed to brake fluids, hydrazine and ketones. Fluorosilicone should not be confused with silicone in regard to high heat resistance. |
Fluoro Elastomers have high heat resistance up to 600°F, and resistance to a wide reange of oils and solvents; especially all aliphatic, aromatic and halogenated hydrocarbons, acids, animal and vegetable oils. Fluoro Elastomers are not recommended for ketones, low molecular weight esters and nitro containing compounds. |
Natural Rubber | SBR | |
Common Names | Natural Rubber | SBR, GRS |
ASTM D-2000 Classification | AA | AA, BA |
Military (MIL STD 417) | RN | RS |
Chemical Definition | Polyisoprene | Styrene Butadiene |
General Characteristics | ||
Durometer Range (Shore A) | 20 - 100 | 30 - 100 |
Tensile Range (P.S.I.) | 500 - 3500 | 500 - 3000 |
Elongation (Max %) | 700 | 600 |
Compression Set | Excellent | Good |
Resilience - Rebound | Excellent | Good |
Abrasion Resistance | Excellent | Excellent |
Tear Resistance | Excellent | Fair |
Solvent Resistance | Poor | Poor |
Oil Resistance | Poor | Poor |
Low Temperature Usage (F°) | -20° to -60° | 0° to -50° |
High Temperature Usage (F°) | to 175° | to 225° |
Aging Weather - Sunlight | Poor | Poor |
Adhesion to Metals | Excellent | Excellent |
Comment |
Natural Rubber has many good characteristics. It has high resilience, good compression set, food roll building behavior, and molding properties; very good friction surface, but not a fine smooth surface when ground; high tear strength, low crack growth; usable for ketones and alcohol; and good low temperature properties. Natural Rubber is not recommended for oil and solvent resistance and ozone attacks it. |
SBR is a low cost non-oil resistant material. It has good water resistance and resilience up to 70 durometer; compression set becomes poorer with higher durometer; generally satisfactory for most moderate chemicals and wet or dry organic acids. SBR is not recommended for ozone, strong acids, oils, greases, fats and most hydrocarbons. |
Urethane | Butyl | |
Common Names | Urethane, Polyurethane | Butyl |
ASTM D-2000 Classification | BG | AA, BA |
Military (MIL STD 417) | SB | RS |
Chemical Definition | Polyester/Polyether Urethane | Isobutylene Isoprene |
General Characteristics | ||
Durometer Range (Shore A) | 35 - 100 | 40 - 90 |
Tensile Range (P.S.I.) | 500 - 6000 | 500 - 3000 |
Elongation (Max %) | 750 | 850 |
Compression Set | Poor | Fair to Good |
Resilience - Rebound | Good | Fair |
Abrasion Resistance | Excellent | Fair |
Tear Resistance | Excellent | Good |
Solvent Resistance | Poor | Poor |
Oil Resistance | Good | Poor |
Low Temperature Usage (F°) | -10° to -30° | -10° to -60° |
High Temperature Usage (F°) | to 175° | to 250° |
Aging Weather - Sunlight | Excellent | Excellent |
Adhesion to Metals | Fair to Good | Good |
Comment |
The castable types have excellent abrasion resistance; good compression set at high hardness levels; low friction surface; tensile strengths up to 6000 PSI; good ozone resistance; good oil and solvent resistance; and poor heat and hot water resistance. The millable types of Polyurethane are in wide use today. Through the use of reinforcing pigments and other chemicals, desirable characteristics can be obtained to fit a variety of applications: wear resistance is excellent and greatly superior to most other polymers; the surface is of low friction nature; oil resistance is good and equivalent to the better nitriles but is not recommended for use in water or heat above 175°F; plus good ozone resistance and low rebound characteristcs. Urethane is not normally attacked by moderate chemicals and hydrocarbons. It is generally attacked by concentrated acids, ketones, chlorinated and nitro hydrocarbons. |
Butyl rubber is impermeable to most common gasses and has good resistance to sunlight and ozone. Butyl is normally satisfactory when exposed to animal and vegetable oils and oxidizing chemicals. Butyl is not recommended for use with petroleum solvent, coal tar and aromatic hydrocarbons. |
Hydrin | Hypalon | |
Common Names | Hydrin | Hypalon |
ASTM D-2000 Classification | CH, DK, DJ | CE |
Military (MIL STD 417) | SB | SC |
Chemical Definition | Epichlorohydrin | Chlorosulfonated/polyethylene |
General Characteristics | ||
Durometer Range (Shore A) | 40 - 90 | 45 - 100 |
Tensile Range (P.S.I.) | 500 - 2500 | 1000 - 3000 |
Elongation (Max %) | 350 | 500 |
Compression Set | Good | Fair |
Resilience - Rebound | Good | Fair |
Abrasion Resistance | Good | Excellent |
Tear Resistance | Good | Good |
Solvent Resistance | Good | Fair to Good |
Oil Resistance | Excellent | Fair to Good |
Low Temperature Usage (F°) | -15° to -50° | -30° to -60° |
High Temperature Usage (F°) | to 225° | to 225° |
Aging Weather - Sunlight | Good | Excellent |
Adhesion to Metals | Good | Excellent |
Comment |
Epichlorohydrin is an outstanding polymer, exhibiting most of the better qualities of nitrile and neoprene, but having additional plus features: oil and solvent resistance is very good. Hydrin has especially low swell in gasoline; low temperature performance is better than either nitrile or neoprene, and offers less torsional stiffness at sub zero temperatures; high temperature endurance is good up to 250°F; resilience is good and compression set is fairly good in many compounds; abrasion is equivalent to the nitriles; and ozone weathering and water resistance are very good. Epichlorohydrin is generally attacked by ketones, esters, aldehydes, chlorinated and nitro hydrocarbons. |
Hypalon has very good resistance to oxidation and ozone, as well as good flame resistance; it is similar to neoprene except with improved acid resistance; abrasion resistance is excellent, about the equivalent of nitrile, low friction surface; and oil and solvent resistance about intermediate between neoprene and nitrile. Hypalon is not recommended for exposure to concentrated oxidizing acids, esters, ketones, chlorinated, aromatic and nitro hydrocarbons. Hypalon is recommended for immersion in water. |