EPDM vs. NR

Attribute	EPDM	NR
Chemical structure	ethylene propylene diene monomer	natural rubber
Origin	Synthetic	Natural
Temperature resistance	Excellent	Good
Weather resistance	Excellent	Good
Chemical resistance	Good	Poor

Introduction

EPDM (ethylene propylene diene monomer) and NR (natural rubber) are two commonly used elastomers in various industries. Both materials have unique properties that make them suitable for different applications. In this article, we will compare the attributes of EPDM and NR to help you understand their differences and choose the right material for your specific needs.

Physical Properties

EPDM is a synthetic rubber that is known for its excellent weather resistance, ozone resistance, and heat resistance. It can withstand temperatures ranging from -50°C to 150°C, making it ideal for outdoor applications. On the other hand, NR is a natural rubber that offers good elasticity and resilience. It has a lower temperature resistance compared to EPDM, with a range of -50°C to 70°C.

EPDM has a higher tensile strength and tear resistance than NR, making it more durable and long-lasting. NR, on the other hand, has superior abrasion resistance and low-temperature flexibility. Both materials have good compression set properties, but EPDM tends to perform better in this aspect.

Chemical Resistance

EPDM is resistant to a wide range of chemicals, including acids, alkalis, and polar solvents. It is not recommended for use with oils, fuels, and hydrocarbons, as it can swell and degrade in these environments. NR, on the other hand, is not as chemically resistant as EPDM and is susceptible to degradation when exposed to oils and solvents.

EPDM is also resistant to steam and hot water, making it suitable for applications where these substances are present. NR, on the other hand, may swell and degrade when exposed to hot water and steam, limiting its use in such environments.

Weather Resistance

EPDM is known for its excellent weather resistance, making it ideal for outdoor applications where exposure to sunlight, ozone, and extreme temperatures is common. It does not degrade or become brittle when exposed to UV radiation, unlike NR, which can deteriorate when exposed to sunlight for extended periods.

NR is more prone to weathering and ozone cracking compared to EPDM, making it less suitable for outdoor applications where weather resistance is crucial. EPDM's superior weather resistance also makes it a preferred choice for roofing membranes, seals, and gaskets in outdoor environments.

Applications

EPDM is commonly used in automotive seals, weatherstripping, roofing membranes, and electrical insulation due to its excellent weather resistance and durability. It is also used in the construction industry for window seals, expansion joints, and waterproofing applications. NR, on the other hand, is used in tires, conveyor belts, footwear, and other applications that require good elasticity and resilience.

• EPDM applications:
• Automotive seals
• Roofing membranes
• Electrical insulation
• Construction seals
• NR applications:
• Tires
• Conveyor belts
• Footwear
• Seals and gaskets

Conclusion

In conclusion, EPDM and NR are two versatile elastomers with unique properties that make them suitable for different applications. EPDM offers excellent weather resistance, chemical resistance, and durability, making it ideal for outdoor and automotive applications. NR, on the other hand, provides good elasticity, resilience, and abrasion resistance, making it a preferred choice for tires, conveyor belts, and footwear.

When choosing between EPDM and NR, consider the specific requirements of your application, such as temperature range, chemical exposure, and weather resistance. By understanding the attributes of each material, you can make an informed decision and select the right elastomer for your needs.