NBR vs. EPDMJohn Moot
NBR vs. EPDM: What is the difference?
Synthetic rubber comes in nearly a dozen major types with different properties for different applications. Two common synthetic rubber compounds are known as EPDM and nitrile rubber. The major differences between these two rubber products are their resistance to petroleum-based fuels and lubricants and their resistance to weathering.
The main difference between NBR and EPDM is that NBR is a non-aromatic polymer compound, while EPDM is an aromatic polymer.
NBR and EPDM are two types of rubber materials. Rubber is a material that can stretch when an external force is applied and sink back to its original shape after the applied force is removed. Natural rubber, which is derived from the milky sap of the rubber tree, is the most common way to make rubber-like materials; however, there are also synthetic ways.
What is NBR?
The term NBR stands for nitrile butadiene rubber. It is also known as nitrile rubber, Buna-N, and acrylonitrile butadiene rubber. It is a synthetic form of rubber made from the monomers acrylonitrile and butadiene. The most common trade names for this rubber are Perbunan, Nipol, Krynac and Europrene.
NBR material is unusually resistant to oil, fuel and most chemicals. Therefore, it is used in the automotive and aerospace industries to make hoses, seals, grommets, and fuel tanks for fuel and oil.
Also, NBR is used in the nuclear industry to make protective gloves. This material has very high stability in the temperature range from minus 40 degrees Celsius to 108 degrees Celsius. This makes it an ideal material for aerospace applications. In addition, NBR is important for the production of molded articles, shoes, adhesives, sealants, sponges, foams and floor mats.
The exceptional elasticity of NBR also makes it important for the production of disposable laboratory items, cleaning purposes and examination gloves. Compared to natural rubber (NR), NBR is more resistant to oils and acids. NBR also has higher strength and does not cause allergic reactions (natural rubber can cause allergic reactions on the skin).
Advantages of NBR
- excellent compression set
- good tear resistance
- good abrasion resistance
- good resistance to mineral oil based oils
- good resistance to mineral oil based hydraulic fluids
- good resistance to solvents, water and alcohols
Disadvantages of NBR
- poor resistance to weathering
- moderate heat resistance
- not suitable for use in brake fluids
- not suitable for use in highly polar solvents
What is EPDM?
The term EPDM stands for ethylene propylene diene monomer rubber. It is a type of synthetic material that belongs to the group of elastomers and consists of saturated polyethylene chains. EPDM is an aromatic compound. The monomers used to produce this polymer material are ethylene, propylene and a diene comonomer. Its structure allows crosslinking by sulfur vulcanization.
The presence of a saturated component makes EPDM much more resistant to heat, light and ozone compared to the other unsaturated rubber materials such as natural rubber, SBR and neoprene. In addition, EPDM can be formulated into a temperature-resistant form of the polymer that can withstand temperatures up to about 150 degrees Celsius. It can be used outdoors for many years without deteriorating. In addition, this material has good low-temperature properties such as elasticity.
Advantages of EPDM
- excellent resistance to weathering and ozone
- excellent resistance to water and chemicals
- excellent resistance to gas permeability and aging due to steam action
- good in ketones and alcohols
- good heat resistance
- good low-temperature flexibility
Disadvantages of EPDM
- poor resistance to fuels and solvents
- not recommended for food applications
- not recommended for contact with aromatic hydrocarbons
What is the difference between NBR and EPDM?
NBR and EPDM are two types of rubber materials. NBR stands for nitrile butadiene rubber, while EPDM stands for ethylene propylene diene monomer rubber. The main difference between NBR and EPDM is that NBR is a non-aromatic polymer compound, while EPDM is an aromatic polymer. Also, NBR is made from the monomers acrylonitrile and butadiene, while EPDM is made from ethylene, propylene and a diene comonomer.
Summary – NBR vs. EPDM
EPDM, or ethylene-propylene-diene monomer, is widely used to make O-rings, washers and other seals in water and steam pipes, as well as in cooling and braking systems in cars and trucks. EPDM seals are resistant to mild acids, detergents, silicones, glycols, ketones and alcohols, and can withstand temperatures from -30C to +150 C. They are resistant to ozone. The major weakness of EPDM rubber gaskets and other seals is that they fail and exhibit poor sealing performance in systems that use petroleum-based fuels, oils and solvents.
Nitrile rubber, also known as Buna-N, Perbunan, Nipol, Krynac and Europrene is made by combining the polymers butadiene and acrylonitrile. It offers excellent resistance to gasoline, diesel fuel, motor oil and other petroleum-based products.
For this reason, it is widely used for washers and O-rings that seal fuel systems of automobiles, boats, aircraft and stationary engines.
It can be formulated to withstand temperatures from -55 C to 135 C. The main disadvantage of nitrile rubber is that it can be affected by sunlight, general weathering or ozone from electrical equipment, unless it has been specifically manufactured for these purposes.
Stamped parts made of EPDM and NBR
Dr. Dietrich Mueller GmbH manufactures stamped parts, strips and blanks from both materials. The processes used are water jet cutting, punching and roll cutting.