Nitrile is a synthetic rubber made from two chemical building blocks: butadiene and acrylonitrile. These two petroleum-derived compounds are combined through a process called emulsion polymerization, producing a material formally known as nitrile butadiene rubber (NBR). Most commercial nitrile products contain between 27% and 42% acrylonitrile, with butadiene making up the rest.
The Two Building Blocks
Butadiene is a gas derived from petroleum refining. It gives nitrile rubber its flexibility and resilience, the stretchy quality you notice when pulling on a nitrile glove. Acrylonitrile, also sourced from petroleum, contributes chemical resistance. The more acrylonitrile in the mix, the better the material resists oils, fuels, and solvents, but the stiffer and less flexible it becomes.
Manufacturers can combine these two monomers in almost any proportion, but practical formulations range from 18% to 50% acrylonitrile. The sweet spot for most everyday products like disposable gloves and seals sits in the 27% to 42% range, balancing flexibility with chemical protection. A glove designed for automotive mechanics handling petroleum-based fluids would lean toward the higher end, while one prioritizing comfort and dexterity might sit lower.
How Nitrile Rubber Is Made
Nitrile is produced through emulsion polymerization, a process where the two liquid monomers are mixed with water, soap-like emulsifiers, and chemical agents that trigger the reaction. In industrial settings, this mixture flows through a series of connected reactors, often seven in sequence. The monomers enter the first reactor and gradually link together into long polymer chains as they pass through each stage. By the time the material exits the final reactor, it has formed into nitrile rubber.
Additional chemicals called accelerators are added during a later step known as vulcanization, which cross-links the polymer chains and gives the rubber its final strength and elasticity. Common accelerator families include dithiocarbamates and thiazoles. These chemicals are worth knowing about because they’re the primary cause of skin reactions in people who develop contact allergies to nitrile gloves (more on that below).
Why Nitrile Replaced Latex in Many Products
Natural rubber latex comes from the sap of rubber trees and contains proteins that trigger true allergic reactions in some people, ranging from skin irritation to anaphylaxis. Nitrile, being entirely synthetic, contains none of these proteins. That distinction drove its widespread adoption in healthcare, food handling, and laboratory work starting in the 1990s.
Performance also plays a role. Research published in the British Dental Journal found that nitrile gloves had significantly higher puncture resistance than latex gloves when tested with a standard steel probe, along with greater stiffness. Interestingly, latex outperformed nitrile when the puncture came from a sharp dental needle, suggesting neither material is universally superior. Nitrile gloves also became stiffer and more puncture-resistant as they aged, while latex tends to degrade over time.
Operating Limits and Weaknesses
Standard nitrile rubber performs well between roughly negative 35°C and 120°C (negative 30°F to 250°F). Below that range it becomes brittle; above it, the material softens and loses its structural integrity. That temperature window covers most everyday and moderate industrial applications, from automotive gaskets to medical gloves, but falls short for extreme environments.
For harsher conditions, manufacturers produce hydrogenated nitrile butadiene rubber (HNBR). This is standard nitrile that undergoes an additional chemical process to saturate the polymer chains, making it more resistant to heat, ozone, and aggressive chemicals. HNBR can handle temperatures up to 150°C (302°F) or higher, with improved tensile strength and a longer lifespan. It’s commonly found in oil field equipment, automotive timing belts, and aerospace seals where standard nitrile would break down.
One consistent weakness across all nitrile formulations: poor resistance to ketones and certain strong solvents like acetone. If your work involves those chemicals, nitrile gloves or seals are the wrong choice regardless of the acrylonitrile content.
Skin Reactions From Nitrile
While nitrile eliminates the protein-based latex allergy risk, it can still cause a different type of skin reaction. The vulcanization accelerators used during manufacturing, particularly dithiocarbamates and thiazoles, are known to trigger delayed-type contact dermatitis. This shows up as itchy, red, sometimes blistered skin on the hands, typically appearing hours to days after glove use rather than immediately.
Older nitrile formulations relied heavily on thiuram accelerators, which caused high rates of sensitization. Most modern manufacturers have shifted to dithiocarbamates, which produce fewer reactions. Some companies now offer “accelerator-free” nitrile gloves for workers who’ve developed sensitivities, though these tend to cost more. If you’re experiencing recurring hand eczema from glove use, patch testing can identify which specific accelerator is causing the problem.
Environmental Footprint
Standard nitrile does not biodegrade quickly. Thermal degradation studies estimate a lifespan of roughly 35 years for a small piece of NBR at elevated temperatures. Given that billions of disposable nitrile gloves enter landfills each year, this is a growing concern.
Lab research has explored using specific bacteria to break down nitrile rubber. One study using Pseudomonas aeruginosa achieved a 2.25% weight loss in nitrile glove samples over a test period, a rate that would project to complete degradation in about 311 days under those controlled conditions. That’s promising compared to the decades-long timeline for standard decomposition, but these are laboratory results, not real-world landfill conditions. Some manufacturers now market “biodegradable” nitrile gloves that incorporate additives designed to accelerate microbial breakdown, though the actual degradation rates in typical landfill environments remain debated.
Where Nitrile Shows Up Beyond Gloves
Disposable gloves get the most public attention, but nitrile rubber’s chemical resistance makes it a workhorse across industries. Common applications include:
- Automotive: Fuel hoses, gaskets, O-rings, and oil seals that need to resist petroleum products
- Aerospace: Seals and gaskets in fuel systems, often using HNBR for its higher temperature tolerance
- Oil and gas: Blowout preventers, wellhead seals, and downhole equipment exposed to crude oil and high pressures
- Printing: Rollers and blankets that contact petroleum-based inks
- Footwear: Soles for work boots requiring oil and abrasion resistance
The material was first patented in 1934 by German chemists Erich Konrad and Eduard Tschunkur under the name Buna N. Nearly a century later, the core chemistry remains the same: two petroleum-derived monomers combined in varying ratios to balance flexibility, strength, and chemical resistance for whatever the application demands.