When sourcing high-performance elastomers for critical sealing applications, you might encounter the terms FFKM and FFPM. Both materials represent top-tier sealing solutions, especially in harsh chemical and high-temperature environments—but do these terms refer to the same material, or are there distinctions?
FFKM (Perfluoroelastomer)refers explicitly to elastomers fully fluorinated with no hydrogen atoms remaining, providing unmatched chemical and temperature resistance. FFPM, while often used interchangeably with FFKM, originates from European standards (ISO 1629) and can sometimes encompass slightly broader formulations, though in practical industrial use, the terms are generally synonymous.
Below, I’ll explain the precise differences and similarities between these two terms, including their chemical compositions, naming conventions, and performance applications.
What is FFKM?
FFKM (Perfluoroelastomer) is a fully fluorinated elastomer where all hydrogen atoms are replaced by fluorine, resulting in extraordinary chemical stability and resistance to high temperatures and aggressive chemicals.
Key Properties of FFKM:
- ✅ Fully fluorinated structure (no hydrogen).
- ✅ Excellent chemical resistance1 to acids, bases, solvents, and oxidizers.
- ✅ Outstanding thermal stability2 (up to ~327°C or 620°F depending on grade).
- ✅ Superior mechanical properties3 such as elasticity, resilience, and compression set resistance.
Typical Applications of FFKM:
| Industry | Typical Applications |
|---|---|
| Chemical Processing | Aggressive chemical sealing, valves, pumps |
| Aerospace | Fuel system seals, hydraulic seals |
| Semiconductor | High-purity seals, wafer-processing equipment |
| Oil & Gas | Extreme-pressure and temperature seals |
Popular FFKM Brands:
- Kalrez® (DuPont)
- Chemraz® (Greene Tweed)
- Perlast® (Precision Polymer Engineering)
What is FFPM?
FFPM is a designation primarily used in European standards (ISO 1629) referring to fluorinated fluoropolymer elastomers. While frequently used interchangeably with FFKM, the term FFPM can sometimes encompass a slightly broader range of perfluorinated elastomers, potentially including elastomers that might not be fully fluorinated at a strictly defined chemical level.
In practice, most commercially available FFPM materials are fully perfluorinated, essentially making FFPM equivalent to FFKM in practical applications.
Key Characteristics of FFPM:
- ✅ Derived from European ISO/DIN standard terminology.
- ✅ Typically fully fluorinated elastomers (similar to FFKM).
- ✅ Excellent chemical and temperature resistance1, though exact properties depend on specific manufacturer formulations.
Key Differences Between FFKM and FFPM:
Though often synonymous in industrial use, some subtle distinctions exist:
| Feature | FFKM | FFPM |
|---|---|---|
| Naming Convention | ASTM (American standard) | ISO/DIN (European standard) |
| Chemical Composition | Fully fluorinated elastomer (no hydrogen atoms) | Typically fully fluorinated; occasionally broader definitions |
| Global Recognition | Widely recognized and standardized globally | More common in European documentation |
| Typical Use in Industry | Common in US/global markets | Primarily seen in European standards |
Practical Comparison (Performance & Applications):
Despite minor naming variations, both FFKM and FFPM usually deliver identical performance characteristics in real-world sealing applications:
- Chemical Resistance: Both offer nearly universal chemical compatibility, resisting aggressive chemicals like acids, alkalis, solvents, and fuels.
- Temperature Resistance: Exceptional high-temperature stability (up to ~327°C).
- Mechanical Performance: Superior elasticity, compression set resistance, and durability in harsh environments.
Thus, from a practical and industrial standpoint, FFKM and FFPM are generally considered equivalent, and the differences are primarily in the nomenclature and standards used.
Which Term Should You Use?
✅ Use "FFKM" if:
- You work primarily with ASTM standards or North American/global specifications.
- You require clear, standardized documentation or sourcing from well-known global brands (Kalrez®, Chemraz®).
✅ Use "FFPM" if:
- You adhere to ISO/DIN European standards and specifications.
- Your supply chain or technical documentation follows European naming conventions.
In most practical sealing applications, either term will effectively communicate your needs.
Conclusion
FFKM and FFPM are both high-performance elastomers, generally considered equivalent in industrial use. The primary difference lies in their naming conventions (ASTM vs. ISO/DIN) and minor variations in standard definitions. Both provide outstanding performance in challenging sealing applications, so understanding this distinction helps clarify communication within global supply chains.
Understanding chemical resistance is crucial for selecting materials that withstand harsh environments, ensuring safety and longevity in applications. ↩ ↩
Exploring thermal stability helps in choosing materials that maintain integrity under high temperatures, essential for many industrial applications. ↩
Learning about mechanical properties is vital for selecting the right elastomer for specific applications, ensuring optimal performance and durability. ↩
