EPDM vs. FPM

Attribute	EPDM	FPM
Chemical Resistance	Excellent	Good
Temperature Range	-50°C to 150°C	-20°C to 200°C
Hardness	40-90 Shore A	60-90 Shore A
Compression Set	Good	Excellent
Cost	Lower	Higher

Introduction

EPDM (ethylene propylene diene monomer) and FPM (fluorocarbon rubber) are two popular elastomers used in various industries for their unique properties and applications. While both materials offer excellent resistance to heat, chemicals, and weathering, they have distinct differences that make them suitable for specific uses. In this article, we will compare the attributes of EPDM and FPM to help you understand their strengths and weaknesses.

Chemical Composition

EPDM is a synthetic rubber made from ethylene, propylene, and a diene monomer. It is known for its excellent resistance to ozone, UV radiation, and weathering, making it a popular choice for outdoor applications. On the other hand, FPM is a type of fluoroelastomer that contains fluorine atoms in its chemical structure. This gives FPM exceptional resistance to chemicals, oils, and high temperatures, making it ideal for use in harsh environments.

Physical Properties

EPDM is known for its flexibility, good electrical insulation properties, and low temperature resistance. It has a wide temperature range of -50°C to 150°C, making it suitable for both hot and cold environments. FPM, on the other hand, has a higher temperature resistance, with a range of -20°C to 200°C. It also has excellent resistance to compression set, making it ideal for sealing applications where resilience is crucial.

Mechanical Properties

EPDM has good tensile strength, tear resistance, and elongation properties, making it suitable for applications that require flexibility and durability. It is commonly used in roofing membranes, automotive seals, and weatherstripping. FPM, on the other hand, has higher tensile strength and tear resistance than EPDM, making it ideal for applications that require resistance to abrasion and wear, such as O-rings and gaskets.

Chemical Resistance

EPDM has good resistance to acids, alkalis, and polar solvents, but it may not be suitable for applications that require resistance to oils, fuels, and hydrocarbons. FPM, on the other hand, has excellent resistance to a wide range of chemicals, including oils, fuels, and solvents. It is commonly used in the automotive and aerospace industries for sealing applications where exposure to harsh chemicals is a concern.

Weathering and UV Resistance

EPDM is known for its excellent weathering and UV resistance, making it a popular choice for outdoor applications such as roofing, window seals, and garden hoses. It does not degrade easily when exposed to sunlight, ozone, or extreme temperatures. FPM, on the other hand, also has good weathering and UV resistance, but it may not be as durable as EPDM in prolonged outdoor exposure due to its higher temperature resistance.

Cost and Availability

EPDM is a cost-effective material that is widely available in various forms, including sheets, rolls, and extrusions. It is commonly used in construction, automotive, and marine industries due to its affordability and versatility. FPM, on the other hand, is a more expensive material compared to EPDM, but its superior chemical resistance and high temperature capabilities justify the higher cost for certain applications.

Conclusion

In conclusion, EPDM and FPM are two versatile elastomers with unique properties that make them suitable for a wide range of applications. While EPDM is known for its excellent weathering resistance and flexibility, FPM offers superior chemical resistance and high temperature capabilities. The choice between EPDM and FPM ultimately depends on the specific requirements of the application, such as temperature range, chemical exposure, and mechanical properties. By understanding the attributes of EPDM and FPM, you can make an informed decision on which material is best suited for your needs.