Choosing the right elastomer for an inflatable seal can make or break your system’s performance. If a material softens, cracks, or swells when exposed to certain chemicals, leaks and contamination follow. Whether your operation involves solvents, acids, oils, or cleaning agents, chemical compatibility must come first. A mismatch between the environment and the seal material can shorten service life and increase maintenance costs.
Selecting the correct compound is rarely straightforward. You are often dealing with complex mixtures, including cleaning chemicals, lubricants, and varying temperatures, all of which influence how a seal behaves.
Luckily, this guide will show you how to select seals based on your facility’s chemical environments.
Why Chemical Compatibility Matters
Inflatable seals operate under pressure, often in systems where chemical contact is unavoidable. Exposure does not always cause immediate damage. Degradation often begins invisibly at the molecular level. Swelling, hardening, or cracking may appear after hundreds of inflation cycles, leading to poor sealing and eventual failure.
In demanding environments, it is not enough to rely on a single resistance property. A material that withstands one substance may react badly with another. Balancing resistance to different fluids while maintaining elasticity and sealing power is the essence of proper selection.
Nitrile (NBR): Strong Against Oils and Hydrocarbons
Nitrile rubber is widely used in systems exposed to petroleum-based oils, fuels, and lubricants. It resists swelling and retains its shape when in contact with hydrocarbon fluids, making it reliable for hydraulic and mechanical equipment. It also offers good tensile and tear strength, which supports long-term inflation cycles.
Its limitation is in polar solvents and strong oxidizing agents. Alcohols, ketones, and certain cleaning solutions can attack the polymer, causing brittleness over time.
EPDM: Ideal for Steam and Cleaning Agents
Ethylene propylene diene monomer (EPDM) performs exceptionally well in applications involving water, steam, and polar fluids. It stands up to many alkaline and oxidizing cleaners and remains flexible through heat cycles. It is also resistant to ozone and UV exposure, which adds to its stability in outdoor or humid conditions.
EPDM’s weakness lies in its poor resistance to oils and hydrocarbons. Where petroleum-based fluids or solvent mixtures are present, it should be avoided.
Fluorocarbon (Viton): Resistant to Solvents and Acids
Fluorocarbon elastomers are a top choice for systems handling strong solvents, fuels, or acids under elevated temperatures. They retain elasticity where other compounds would degrade, maintaining a seal in chemical processing, aerospace, or high-temperature manufacturing. Their dense molecular structure provides exceptional resistance to a wide chemical range, including oils and many cleaning agents.
They are, however, less flexible in very cold environments and typically more expensive. Still, for critical containment where failure cannot be tolerated, fluorocarbon’s stability and lifespan often justify the investment.
Silicone (VMQ): Flexible and Clean
Silicone elastomers maintain flexibility across extreme temperature ranges, making them valuable in environments that alternate between hot and cold. They resist oxidation and mild chemicals, which suits applications requiring frequent sanitation. Silicone is often chosen where purity and cleanliness are as important as sealing capability, such as in laboratories or medical processing systems.
However, silicone’s resistance to mineral oils and concentrated solvents is limited. Long-term contact with these chemicals can cause swelling and reduced strength. For operations dominated by oils or strong solvents, nitrile or fluorocarbon will provide longer service life.
Neoprene (Chloroprene): Balanced for Moderate Exposure
Neoprene offers moderate resistance to oils, greases, and many common cleaning agents. It performs well when chemical exposure is intermittent rather than constant. It also provides flame resistance and good mechanical properties, which can be beneficial in mixed-environment operations.
Its limitation lies in aggressive chemical applications. Strong acids, aromatic solvents, or high-concentration oxidizers will eventually compromise neoprene’s structure.
Polyurethane: Durable and Wear-Resistant
Polyurethane stands out for its mechanical toughness. It resists abrasion, tearing, and many oils and solvents, making it well-suited for systems that combine mechanical stress with mild chemical exposure. It is frequently used when seals must endure repeated inflation cycles in abrasive or fluid-rich environments.
However, certain acids and highly polar solvents can attack polyurethane over time. It is important to confirm compatibility with specific chemicals rather than assume universal resistance.
Making the Right Choice
No single elastomer performs best in every chemical environment. Each has strengths and weaknesses that depend on the fluids, temperatures, and cleaning routines in your process. Compatibility testing, operating temperature range, and duty cycle all determine whether a seal continues to perform after thousands of cycles or fails unexpectedly.
Material selection should always begin with a complete understanding of the environment. Identify the chemicals in use, note whether they are oils, solvents, or cleaners, and consider how temperature and pressure may amplify their effects. From there, match these conditions with the properties of each elastomer to ensure long-term reliability.
Choose Seal Expertise You Can Rely On
Selecting the wrong seal material can cost more than just downtime. It can jeopardize containment, equipment integrity, and safety. Seal Master Corporation helps you navigate the chemical and mechanical variables that define your environment. Our engineering team designs inflatable seals using materials proven to withstand your specific chemical exposures, ensuring optimal performance and compliance.
If you are evaluating materials for a system that handles aggressive fluids, let’s get the selection right the first time.
Contact Seal Master Corporation today to discuss your application and find the most chemically compatible solution for your inflatable seals.