Silicone vs EPDM vs Viton vs Nitrile: Choosing the Right Elastomer

Selecting the right elastomer is one of the most consequential decisions in designing a seal, gasket, tube, or molded rubber part. Four families dominate industrial sealing: silicone (VMQ), EPDM, Viton / FKM, and nitrile / NBR (Buna-N). Each has a distinct sweet spot in temperature range, chemical compatibility, weathering, and cost. This guide compares them neutrally on well-established materials-engineering fundamentals so you can match the material to the application — and shows where silicone is the honest best fit.

The four elastomer families at a glance

Every elastomer trades one property for another. There is no single “best” rubber — only the best material for a given combination of temperature, media, environment, and budget. The summary below reflects widely published ranges from general elastomer references; always confirm exact figures against a specific compound and cure.

Silicone (VMQ): temperature range, purity, and weathering

Silicone rubber is a synthetic elastomer built on a silicon–oxygen backbone rather than a carbon backbone, which gives it an exceptionally wide usable temperature window and outstanding resistance to UV, ozone, and general weathering. It stays flexible in the cold and holds its properties at high heat far better than most organic rubbers.

On Exactsilicone’s own product pages, silicone tubing is published to operate across a range of −80°F to +450°F, in durometers from 20 Shore A up to 80 Shore A, and is available as platinum-cured and peroxide-cured material with USP Class VI and FDA grades, plus resistance to UV and ozone. Silicone is also odorless, tasteless, and available in food- and medical-grade formulations — which is why it dominates in medical, pharmaceutical, food-and-beverage, and clean-process applications.

Where silicone wins honestly: extreme hot/cold cycling, sunlight and outdoor exposure, biocompatible and sanitary contact, electrical insulation, and applications that need flexibility over a huge temperature span. Where it does not: silicone has relatively low tensile and tear strength versus some rubbers, and it is not the right choice for continuous contact with petroleum oils, fuels, or many concentrated solvents — that is nitrile or Viton territory.

Typical silicone applications

• Medical and pharmaceutical tubing, sanitary process lines, and food-contact seals
• High-temperature gaskets, oven and appliance seals, LED and lighting seals
• Outdoor and architectural seals exposed to sun, ozone, and weather
• Electrical insulation, keypads, and molded components

EPDM: the outdoor, water, and steam specialist

EPDM (ethylene propylene diene monomer) is prized for excellent resistance to weather, ozone, UV, water, and steam, along with good performance against polar fluids such as glycol-based brake fluids, dilute acids and alkalis, and many ketones. It is an economical, high-volume workhorse for outdoor and water-handling applications.

EPDM’s key limitation is the same as silicone’s: it has poor resistance to petroleum-based oils, fuels, and hydrocarbons, which will swell and degrade it. Choose EPDM for weatherstripping, roofing membranes, automotive cooling systems, potable-water seals, and steam service — not for oil or fuel sealing.

Viton / FKM: the chemical and high-heat champion

Viton is a common trade name for FKM fluoroelastomers. FKM offers the broadest chemical resistance of these four families — standing up to oils, fuels, many aggressive chemicals, and hydrocarbons — combined with strong high-temperature performance. That capability comes at a higher price and, in standard grades, reduced low-temperature flexibility compared with silicone.

Choose Viton / FKM for aggressive chemical exposure, fuel-system and aerospace seals, and sustained high heat in demanding environments. Watch out for very low temperatures, hot water and steam (grade-dependent), and certain polar solvents such as ketones and some amines, where FKM is not the strongest performer.

Nitrile / NBR (Buna-N): the oil and fuel workhorse

Nitrile rubber (NBR), often called Buna-N, is the default economical choice for sealing petroleum oils, fuels, and hydraulic fluids, with good abrasion and mechanical strength. Its acrylonitrile content can be tuned to trade oil resistance against low-temperature flexibility.

Nitrile’s weakness is the environment: it has poor resistance to ozone, UV, sunlight, and weathering, so it is a poor choice for prolonged outdoor exposure. It is the go-to material for fuel and oil seals, hydraulic O-rings, and automotive under-hood components where cost matters and sunlight does not.

How to choose: a practical decision path

• Lead with temperature. Very high or very low service temperatures, or wide swings, point toward silicone (broadest span) or FKM (high-heat with chemical exposure).
• Then screen the media. Petroleum oils and fuels rule out silicone and EPDM — go nitrile (economical) or Viton (aggressive/hot). Water, steam, and weather favor EPDM or silicone.
• Factor the environment. Outdoor UV and ozone exposure favors silicone, EPDM, or FKM and disfavors nitrile.
• Confirm purity needs. Food, medical, and sanitary contact favor silicone with USP Class VI / FDA grades.
• Balance cost. EPDM and nitrile are economical; silicone is moderate; FKM is premium. Match the spend to the requirement, not the other way around.
• Verify the exact compound. Ranges here are general; a specific cure, filler, and durometer can shift limits. Validate against your fluids, pressures, and temperatures before committing.

General elastomer selection references such as the Parker O-Ring Handbook and standard chemical-compatibility charts published by seal and rubber manufacturers are useful cross-checks when narrowing candidates.

Where Exactsilicone fits

Exactsilicone is a US-based custom silicone manufacturer specializing in silicone parts made to your specification — not off-the-shelf stock. If your application lands in silicone’s strengths (wide temperature range, weathering, purity, sanitary or medical contact), we can help you spec and quote the right part. Explore the product lines below and send drawings or requirements for a quote:

• Silicone Tubing — platinum- and peroxide-cured, USP Class VI and FDA grades
• Silicone O-Rings
• Silicone Gaskets
• Extruded Silicone Profiles
• FDA & Medical Grade Silicone Profiles
• Browse all silicone products

Request a quote (RFQ) with your material, dimensions, temperature range, and media, and our team will help confirm whether silicone is the right elastomer for your part.

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