Material Properties Reference

FLUOROCARBON (FPM): Fluorinated hydrocarbon

  • Trade names: Fluorel, Viton
  • Advantages: Outstanding resistance to high heat; excellent resistance to oil, gasoline, hydraulic fluids and hydrocarbon solvents; good flame retardance; very good impermeability to gases and vapor; very good resistance to weather, oxygen, ozone, and sunlight.
  • Limitations: Poor resistance to tear and cut growth; very little resistance to oxygenated solvents; fair adhesion to fabrics and metals.
  • Remarks: Fluorocarbon is a very expensive elastomer with outstanding resistance to a wide variety of oils, fuels, acids, and solvents at elevated temperatures, heat resistance that is almost as good as that of silicone, a resistance to hot oil that exceeds that of acrylic, and weathering properties superior to those of neoprene. Because of its very high price, fluorocarbon is used only in applications requiring excellent stability under extremely severe operating conditions. Subjecting fluorocarbon to a two-stage cure cycle produces the best balance of properties.

SBR (SBR, GR-S, Buna-S): Styrene-Butadiene

  • Trade names: ASRC, Ameripol, Baytown, Carbomix, Copo, FR-S, Gentro, Krylene, Krymix, Krynol, Philprene, Plioflex, Synpol
  • Advantages: Excellent impact strength, very good resilience, tensile strength, abrasion resistance and flexibility at low temperatures.
  • Limitations: Poor resistance to ozone and sunlight; very little resistance to oil; gasoline and hydrocarbon solvents.
  • Remarks: SBR is much like natural rubber in most of its properties and is the lowest cost and highest volume elastomer available. Although the physical properties are slightly poorer than those of natural rubber, SBR is tougher and slightlymore resistant to heat and flex cracking and can be readily substitued for natural rubber in many applications wtih significant cost savings.

EPDM (EPM, EPT): Ethylene-propylene, Ethylene-propylene-diene

  • Trade names: Epcar, Epsyn, Nordel, Royalene, Vistalon
  • Advantages: Excellent resistance to heat; ozone and sunlight; very good flexibility at low temperatures; good resistance to alkalis, acids and oxygenated solvents; superior resistance to water and steam; excellent color stability.
  • Limitations: Poor resistance to oil; gasoline and hydrocarbon solvents; adhesion to fabrics and metal is poor.
  • Remarks: Because of its unique combination of physical properties, EPDM can be used in an unusually broad range of products. Aside from applications requiring resistance to oil and hydrocarbon solvents, there is scarcely an application in which EPDM is totally unsuitable. Because of its excellent resistance to ozone, sunlight and severe weather conditions, EPDM is ideal for outdoor service. In general, EPDM is similar to butyl but has slightly less susceptibilityto contamination. Chlorobutyl (chlorinated version of butyl) is much superior to EPDM in attaining good adhesion to fabrics and metals.

NITRILE (NBR, Buna-N): Acrylonitrile-butadiene

  • Trade names: Breon, Butaprene, Butacril, Chemigum, Chemivic, Elaprim, FR-N, Hycar, Krynac, NYsyn, NYsynblak, Paracril, Paracril OZO, Perbunan N, Tylac, Nipol
  • Advantages: Very good resistance to oil and gasoline; superior resistance to petroleum-based hydraulic fluids; wide range of service temperatures (-65 to 300°F); good resistance to hydrocarbon solvents; very good resistance to alkalis and acids.
  • Limitations: Inferior resistance to ozone, sunlight, and natural aging; poor resistance to oxygenated solvents.
  • Remarks: Nitrile and neoprene are the highest-volume oil-resistant elastomers. Nitrile is superior to neoprene in resistance to oil, gasoline, and aromatic solvents. However, it does not perform as well as neoprene in applications requiring exposure to weather, ozone, and sunlight. Furthermore, it has no inherent flame resistance.

The properties of nitrile vary considerably with the ratio of acrylonitrile and butadiene. In general, as the acrylonitrile content of the elastomer increases, oil and solvent resistance and abrasion resistance improve. When the acrylonitrile content decreases, these properties deteriorate, and low-temperature flexibility and resilience improve.

When nitrile is modified by polyvinyl chloride (PVC) resins, its resistance to weather, ozone, and sunlight improves considerably without significant sacrifice in oil-resisting properties. PVC/nitrile is similar to neoprene, in general, however, it is much inferior to neoprene in adhesion to fabrics and metals.

Carboxylated nitrile is generally tougher and more resistant to tear and abrasion than conventional nitrile, but it is less resilient and flexible at low temperatures.

SILICONE (Si): Polysiloxane

  • Trade names: Gensil, Electrisil, SE, Silastic, SWS
  • Advantages: Outstanding resistance to high heat; excellent flexibility at low temperatures; low compression set; very good electrical insulation; excellent resistance to weather, ozone, sunlight, and oxidation; superior color stability.
  • Limitations: Poor resistance to abrasion, tear, and cut growth; low tensile strength; inferior resistance to oil, gasoline, and solvents; poor resistance to alkalis and acids.
  • Remarks: The most outstanding feature of silicone is its ability to retain rubbery properties through extremes in temperature.  It is the most heat-resisting elastomer in the market today and the most flexible at low temperatures. Service temperatures range from -150 to 500°F. Silicone generally does not have high tensile strength, but much of the strength it does have can be retained at very high temperatures. Because silicone is relatively expensive, it is not normally used unless extreme temperature resistance is essential.

NATURAL RUBBER (NR): Natural Polyisoprene

  • Advantages: Outstanding resilience; high tensile strength; superior resistance to tear and abrasion; excellent rebound elasticity (snap); good flexibility at low temperatures; exellent adhesion to fabric and metals.
  • Limitations: Poor resistance to heat; ozone and sunlight; very little resistance to oil; gasoline and hydrocarbon solvents.
  • Remarks: Natural rubber is a low cost material with excellent physical properties.  Generally speaking it is ideal for applications that require good resistance to abrasion, gouging and cut growth. It is tough and long wearing and can be compounded for service at temperatures as low as -65°F.

ISOPRENE(IR): Synthetic polyisoprene

  • Trade names: Ameripol SN, Natsyn, Trans-PIP
  • Advantages: Outstanding resilience; superior resistance to tear and abrasion; very good tensile strength; excellent rebound elasticity (snap); good flexibility at low temperatures; lack of odor.
  • Limitations: Poor resistance to heat; ozone and sunlight; very little resistance to oil; gasoline and hydrocarbon solvents.
  • Remarks: The chemical composition of isoprene is nearly identical to that of natural rubber.  There the properties of these two elastomers is similar. Isoprene has slightly better resistance to weather and its properties are more consistent because of its purity and uniformity. It is somewhat inferior to natural rubber in tensile strength, tear resistance and compression set.

NEOPRENE (CR): Polychloroprene

  • Trade names: Baypren, Butaclor
  • Advantages: Good inherent flame resistance; moderate resistance to oil and gasoline; excellent adhesion to fabrics and metals; very good resistance to weather, ozone, and natural aging; good resistance to abrasion and flex cracking; very good resistance to alkalis and acids.
  • Limitations: Poor to fair resistance to aromatic and oxygenated solvents; limited flexibility to low temperatures.
  • Remarks: Neoprene is an excellent all-purpose elastomer with a nearly ideal balance of properties and few practical limitations. General purpose neoprenes are classified in two groups; a sulfer-modified type and a mercaptan-modified type. Sulfer-modified neoprene has increased tear strength and resilience and mercaptan-modified neoprene is superior in resistance to heat and compression set.

EPICHLOROHYDRIN (ECO, CO): Epichlorohydrin-ethylene oxide or polyepichlorohydrin

  • Trade names: Herclor, Hydrin
  • Advantages: Excellent resistance to oil and gasoline; superior impermeability to gases and vapor; very good resistance to weather, ozone, sunlight, and oxidation; wide range of service temperatures; good resistance to petroleum-based fluids and solvents.
  • Limitations: Inferior resistance to oxygenated solvents; poor resistance to steam and acids.
  • Remarks: Epichlorohydrin is a specialty polyether elastomer that appears to possess a combination of many desirable properties of nitrile and neopene. On the negative side, its adhesion to fabrics and metals is much inferior to neoprene's and its superior impermeability to gases often causes processing problems and product defects because of air entrapment. Epichlorohydrin is available as a homopolymer (CO) and a copolymer (ECO) of epichlorohydrin containing about 50 percent ethylene oxide. The homopolymer is superior in ozone resistance and gas impermeability and the copolymer is better in resilience and flexibility at low temperatures.

Oil resistance of the homopolymer and the copolymer is about the same. Epichlorohydrin is now also available as a terpolymer of epichlorohydrin, ethylene oxide, and a third monomer. The new terpolymer has properties similar to those of the copolymer. However, unlike the copolymer, the terpolymer can easily be blended with SBR and nitrile, and sulfer cured; and its adhesion to fabrics and metals is reportedly the best among the three versions of epichlorohydrin elastomer.

HYPALON (CSM): Chlorosulfonated polyethylene

  • Trade name: Hypalon
  • Advantages: Good flame retardance; good abrasion resistance; superior resistance to weather, ozone, sunlight, and oxidation; excellent resistance to alkalies and acids; very good color stability; moderate resistance to oil and gasoline.
  • Limitaions: Poor to fair resistance to aromatic solvents; limited flexibility at low temperatures; fair resilience and compression set.
  • Remarks: Hypalon is a close match to neoprene in most properties, but it is superior in resistance to acids, solvents, ozone, and oxidation and has decidedly better color stability.

Rubber Division. (1985). Basic Compounding and Processing of Rubber, 3-11.