High Performance
O-Rings

The highest tier of elastomeric sealing performance

FFKM is the material you reach for when every other elastomer has already been ruled out. With a fully fluorinated backbone, it combines the elastic recovery of a rubber with chemical resistance that approaches PTFE — yet unlike PTFE, it seals dynamically and maintains its cross-linked structure under extreme thermal cycles.

In practice, this means FFKM O-rings are trusted in semiconductor fabs where plasma etching and aggressive cleaning chemicals destroy FKM within weeks, in oil and gas completions where sour gas (H₂S) at high temperature and pressure would cause conventional seals to fail catastrophically, and in pharmaceutical reactors where regulatory compliance demands both chemical purity and seal longevity between maintenance intervals.

• Near-universal chemical resistance including acids, amines, ketones, esters, and halogenated solvents that destroy FKM
• Continuous service capability up to 316°C with minimal compression set — maintaining sealing force over long duty cycles
• Low-temperature variants in the Vertex F range remain flexible down to −40°C for cryogenic and LNG applications
• Metal-ion-free grades available for semiconductor processing where ionic contamination is unacceptable
• Rapid Gas Decompression (RGD/AED) resistant grades for high-pressure gas service in oil and gas applications

The workhorse of tough, oil-rich environments

Produced by selectively hydrogenating standard nitrile rubber (NBR), HNBR eliminates most of the carbon-carbon double bonds that make NBR vulnerable to heat, ozone, and chemical degradation. The result is a material with NBR's familiar oil and fuel resistance, but with dramatically improved thermal stability, mechanical toughness, and resistance to aggressive oilfield chemicals.

Where HNBR really distinguishes itself is in dynamic sealing under mechanical stress. Its tensile strength — which can exceed 30 MPa in filled compounds — combined with exceptional abrasion resistance makes it the default choice for reciprocating rod seals, rotary shaft applications, and any situation where the seal itself sees significant mechanical loading alongside chemical exposure. ISMAT's Vertex H range covers five distinct HNBR compounds, including low-temperature variants engineered to remain flexible down to −40°C.

• Significantly superior heat resistance compared to standard NBR — maintains elasticity at temperatures that cause NBR to harden and crack
• Proven resistance to crude oil, production chemicals, H₂S, CO₂, and amine corrosion inhibitors common in oilfield environments
• Outstanding abrasion and extrusion resistance — well-suited for high-pressure dynamic sealing applications
• Compatible with biodiesel, engine coolants, and refrigerants — broadening its automotive and HVAC application range
• Low-temperature grades (Vertex H 16LT, H 18LT) engineered for arctic oilfield and cold-climate industrial applications

Decades of proven performance across the chemical and energy industries

FKM — commercially known by the trade name Viton® — has been the go-to high-performance elastomer for the chemical processing, automotive, and energy industries for more than half a century. Its exceptional resistance to petroleum-based fluids, acids, and high temperatures gave engineers a reliable step up from standard elastomers at a cost that is significantly more accessible than FFKM.

What makes FKM particularly versatile is the range available within the material family itself. Standard FKM (di-polymer, around 66% fluorine) handles most hydrocarbon and general chemical services effectively. High-fluorine FKM grades (terpolymer, up to 71% fluorine) extend chemical resistance to polar solvents, methanol, and certain ketones. ISMAT's Vertex FC family spans 15 distinct FKM compounds, covering this full breadth of requirements.

• Outstanding resistance to mineral oils, fuels, aromatics, chlorinated solvents, and most inorganic acids
• Continuous service at 200°C+ with low compression set — essential for long service intervals in process equipment
• High-fluorine terpolymer grades (Vertex FC 24ULT, FC 39) offer extended chemical resistance to media outside standard FKM capability
• Peroxide-cured grades deliver improved low-temperature performance and better base resistance than amine-cured equivalents
• Available with FDA-compliant and NORSOK M-710 certified grades where industry qualification is required

The specialist choice where FKM reaches its limits

FEPM — best known commercially as AFLAS® — occupies a very specific and important niche in the high-performance elastomer landscape. It is a copolymer of tetrafluoroethylene and propylene, and this structural difference from FKM gives it a fundamentally different chemical resistance profile: where FKM can be vulnerable to strong bases, amines, and steam at elevated temperatures, FEPM excels.

This makes FEPM the preferred material for geothermal steam service, high-temperature aqueous environments, and oilfield applications where injection chemicals include amines, strong alkalis, or high-pH brines. It is also recognised for high electrical insulation properties, making it valuable in downhole logging tools. ISMAT's Vertex A range offers three FEPM compounds — Vertex A 01, A 02, and A 03 — each developed for specific service conditions.

• Superior resistance to strong bases, amines, and alkali compounds — the application space where FKM frequently fails
• Excellent resistance to high-temperature steam — used in geothermal wells, autoclave systems, and steam-injection oilfield applications
• High dielectric strength makes it suitable for downhole electrical equipment and measurement-while-drilling (MWD) tools
• Good resistance to ozone, weathering, and radiation compared to most other fluoroelastomers
• Broad compatibility with aqueous media, alcohols, engine oils, and ozone-rich environments

Chemically inert by nature, mechanically adapted by design

PTFE's chemical inertness is legendary — there are virtually no solvents, acids, bases, or oxidants that meaningfully attack its molecular structure. This makes it uniquely valuable in sealing applications where chemical compatibility rules out every elastomeric option. The challenge, historically, was that PTFE is not elastic: it does not self-energise the way a compressed rubber O-ring does.

PTFE-coated O-rings resolve this elegantly. An elastomeric core — typically silicone for wide temperature range, or FKM for oil service — provides the elastic recovery that drives the seal, while the encapsulating PTFE layer presents the chemically inert surface to the process media. For applications where even an elastomeric core is unacceptable, ISMAT's Novum PTFE range includes filled formulations (glass-filled, carbon-filled, bronze-filled) for use with appropriate energiser systems.

• Near-universal chemical inertness — resistant to virtually all acids, bases, solvents, and oxidising agents
• Extremely low coefficient of friction reduces stick-slip in dynamic sealing and eases installation in sensitive assemblies
• Non-stick surface prevents adhesion to groove walls, allowing easy inspection and replacement during maintenance
• Colour coding options (white, green, red, blue, yellow) for visual identification during maintenance and QC
• FDA-compliant materials available for food-contact, pharmaceutical, and bioprocessing applications

Not every application needs the highest-tier material

Part of specifying correctly is knowing when a high-performance material is not necessary. A well-matched NBR or EPDM O-ring, properly dimensioned and correctly installed, will out-last a misspecified FFKM seal in the wrong application.

ISMAT's Cerulean elastomeric range covers NBR (nitrile), EPDM, Chloroprene, Silicone, and SBR in a broad range of hardnesses, sizes, and specialty grades — including low-temperature variants and compounds designed for specific fluid compatibility. Our application engineering team helps customers make this call without bias: if an NBR grade does the job, we recommend it; if FFKM is genuinely needed, we tell you why — and we supply both.