Both being synthetic rubbers, nitrile, also known as NBR or Buna-N, share many similarities with silicone rubber. Are you still struggling to decide which material to choose for your product? This article will guide you through the characteristics and applications of these two materials to help you make a better choice.
Similarities Between Silicone and Nitrile
Because they are all a kind of rubber, these two materials share some common characteristics of rubber.
- Both silicone and nitrile are soft elastomers. They change shape when subjected to pressure and return to their original form once the pressure is removed.
- Both silicone and nitrile can be used as insulating materials.
- Silicone and nitrile are thermally stable. Within their operating temperature range, their performance does not easily change with temperature.
- They have sealing and waterproofing capabilities.
Silicone and Nitrile: A Multi-dimensional Comparison
In fact, silicone and nitrile rubber differ significantly in many aspects. These differences are mainly reflected in the following six areas:
Price
Generally, silicone is much more expensive than nitrile, especially when you are purchasing food-grade or medical-grade silicone products. Nitrile products used in industrial applications also have a price advantage, making them the clear winner in terms of short-term costs.
Applicable Temperature Range
Compared to nitrile rubber, a major advantage of silicone is its wider temperature range. Silicone rubber molecules have a silicon-oxygen backbone, which makes them more stable than other rubbers when exposed to temperature changes. It can show excellent performance and work for a long time within a temperature range of -50 °C to 230 °C.
Nitrile rubber can withstand a much lower maximum temperature than silicone rubber, only 121°C. Although nitrile rubber can tolerate low temperatures down to -57°C by reducing the acrylonitrile content, this significantly increases the cost and reduces other properties such as oil resistance.
What’s more, high and low temperatures accelerate the aging of nitrile rubber, leading to more frequent maintenance and replacement. Therefore, choosing silicone would be a wiser decision when dealing with extreme temperatures.
Chemical Compatibility
The biggest difference between silicone and nitrile is their compatibility with various chemical substances.
Chemical Compatibility of Nitrile
Nitrile rubber was originally developed for use in certain fuel systems, so it has excellent oil resistance. Whether it’s gasoline or certain alcohol-based fuels, nitrile rubber maintains its properties well during prolonged contact with them, resisting aging and swelling. Nitrile performs well when in prolonged contact with these substances:
- Most fuels, such as gasoline
- Mineral oils, lubricating oils, hydraulic oils
- Greases
- Alcohol solvents
- Alkaline solutions
But nitrile rubber is not recommended for use in contact with the following chemicals. They will corrode nitrile rubber, significantly shortening its lifespan and causing you equipment and financial losses.
- Ozone
- Ketones, aldehydes, esters
- Strongly acidic substances
- Brake fluid
- strong acid
Chemical Compatibility of Silicone
Silicone is a very stable material with chemical inertness, meaning it does not react with most substances. Even with prolonged contact with these substances, silicone will remain a reliable partner.
- Ozone
- Alcohol, Glycerin
- Weak bases and weak acids
- Oils and fats
- Brake fluid
- Most foods, beverages, human tissues, and bodily fluids
Although silicone has a very wide range of applications, it also has its limitations. When in contact with the following substances, silicone may be corroded, swell, or degrade.
- Fuels, such as diesel fuel
- Some solvents, such as benzene
- Strong acids and bases
- Ketones and esters
- Aromatic hydrocarbons
- Steam at excessively high temperatures
Overall, silicone has stable chemical properties and a wide range of applications, but it is not recommended for use in fuel systems or for transporting certain solvents. For the industrial manufacturing industry, nitrile rubber is a reliable corrosion-resistant material. It is particularly effective against alkaline substances, oils, fuels, and solvents.
Weather Resistance
If you are going to use rubber outdoors, silicone rubber is a better choice. Silicone rubber has excellent weather resistance; it is not only resistant to ultraviolet radiation but also maintains a long service life even in high-concentration ozone environments outdoors, and is not easily weathered.
Nitrile rubber can’t withstand the effects of prolonged exposure to sunlight. Under the influence of UV, it is more prone to photo-oxidative degradation, causing the surface to yellow, crack, and become powdery. At the same time, it loses its original flexibility and is more easily damaged or even broken in two under external force.
Therefore, unless ozone-resistant additives and UV stabilizers are added, nitrile is quite unsuitable for outdoor applications.
Safety
Silicone is a well-known material used in food processing and the medical fields. Of course, not all silicone can be used in these two fields, but food-grade and medical-grade silicone that meets the standards is undoubtedly safer than nitrile. If you are choosing materials for food, drug processing, or medical applications, silicone would be a better choice.
Hypoallergenic
The silicone material itself rarely causes allergic reactions in the human body.
Nitrile is safe for people with latex allergies because it does not contain latex proteins, but the additives in nitrile may cause discomfort.
Chemical Composition
Food-grade and medical-grade silicone don’t lead to harmful substances to
enter the human body, as the additives and catalysts used in the manufacturing process are strictly controlled.
Nitrile may have additives such as acrylonitrile and plasticizers. Even food-grade or medical-grade nitrile used in gloves may release toxic substances when heated to high temperatures.
Long-term Contact
Silicone can be used as a material for human implants. Medical-grade silicone, even when in direct contact with human tissues and cells, does not have harmful effects on the human body.
Nitrile is more commonly used in materials such as disposable medical gloves. It protects the body from harmful chemicals or pathogens during short-term contact, acting as a barrier. Its long-term safety is not as well-established as that of medical-grade silicone.
Abrasion and Tear Resistance
The physical and mechanical properties of silicone and nitrile are actually quite different. Silicone is softer, while nitrile rubber is stronger and more wear-resistant.
Due to its good strength, nitrile is less susceptible to damage from external friction. It is also more puncture-resistant, meaning it is less likely to be scratched or punctured by sharp objects and then lose its protective effect, thus becoming a reliable protective material used in the manufacture of industrial or medical protective gloves.
Nitrile has high tensile strength, making it less likely to crack under stress. These physical properties make nitrile rubber ideal for use in seals that experience frequent movement or in parts that are prone to wear.
Silicone has lower physical and mechanical strength than nitrile rubber. When subjected to friction or sharp objects, the surface of silicone is easily scratched, becoming rough and uneven, significantly reducing its lifespan.
Silicone can be stretched further, but it is also more prone to cracking. However, when compressed, silicone recovers its original shape better after the force is removed, resulting in less deformation than nitrile rubber.
The Better Choice for Different Applications
Due to their different characteristics, silicone and nitrile are better choices for different applications.
Medical, Pharmaceutical, and Healthcare Fields
For these industries with high safety requirements, silicone is a better material. It can be used in products such as teething pads, baby pacifiers, catheters, and drug delivery tubes.
Products made from silicone offer guaranteed quality and eliminate potential safety hazards. Because it can withstand high temperatures, your customers can easily sterilize the products through boiling, and become more confident in product quality.
However, before purchasing in bulk, please ensure that the silicone meets medical-grade standards.
Baking Supplies and Products Requiring Exposure to High Temperatures
Silicone is a more durable and safer material for kitchen utensils and other products exposed to high temperatures. Compared to nitrile rubber, which is suitable for use at normal temperatures, silicone can withstand higher temperatures and performs more stably under high heat.
Even when placed in an oven or in contact with hot pans, silicone baking mats and spatulas won’t release harmful substances or odors into food, affecting its flavor or even threatening customer health.
Industrial Production
In the industrial manufacturing sector, nitrile is a widely used material. Because of its excellent oil resistance, it is used in the manufacture of hose components that come into contact with fuel and oil-resistant conveyor belts. Nitrile pistons that come into contact with hydraulic fluid not only avoid swelling problems but also reduce the frequency of maintenance due to wear, helping you reduce long-term costs.
Seals and Gaskets
Both silicone and nitrile are excellent materials for making seals and gaskets. You can choose the most suitable sealing element according to your needs.
Automotive fuel pumps, hydraulic cylinders, and fuel filler necks require protection against leaks of hydraulic fluid and gasoline, and this is where nitrile O-rings and gaskets are most commonly used. They provide reliable sealing for oil and fuel, ensuring the proper functioning of the machinery.
Silicone O-rings and other sealing components are used for sealing in high-temperature environments. A typical example is their use in coffee machines and other equipment, where not only sealing performance but also safety and high-temperature resistance need to be considered.
Silicone is often chosen as a material for sealing high-temperature electronic components or automotive HVAC systems. Besides being more stable at high temperatures and reducing maintenance time and costs, another reason for choosing silicone is its excellent insulation properties.
Disposable Protective Gloves
As a material for disposable protective gloves, nitrile offers significant advantages. Whether it’s medical examination gloves or the work gloves frequently used by cleaning personnel, there are high demands on the gloves’ abrasion resistance and protection against physical, chemical, and biological hazards. Nitrile is precisely the right material for these applications.
Unlike silicone, nitrile does not become ineffective when contaminated with oil or other substances, so it can more effectively isolate industrial contaminants from the skin, making cleaning easier and ensuring the safety of the glove wearer.
Outdoor Products
Sealants used for sealing doors and windows, as well as gaps in cars and boat hulls, are often made of silicone. For outdoor applications, silicone is a better choice because of its resistance to UV radiation, ozone, water, and mold.
If you are a manufacturer of outdoor sports or leisure products, using durable silicone to make the handles of hiking poles or seat cushions will make your products more resistant to weathering.
FAQ
In Terms of Breathability, Which Is Better: Silicone or Nitrile?
Silicone offers better breathability, while nitrile provides better sealing. Because of the larger intermolecular spacing, gases can pass through silicone material, making it ideal for use in wound dressings. Silicone also has the best moisture permeability among rubber materials. If you require better sealing performance, nitrile effectively prevents gas leakage.
Which Is More Environmentally Friendly, Silicone or Nitrile?
Silicone is more environmentally friendly than nitrile. The primary material for silicone is quartz sand, a natural material, while the production of nitrile rubber requires non-renewable petrochemical raw materials and consumes a lot of energy. Recycling of both materials is limited and requires specialized recycling systems.
Final Thoughts
If you’ve decided to use silicone materials in your products and are looking for cost-effective silicone parts or products, Legensilico can provide you with efficient, one-stop silicone solutions. As a professional Chinese manufacturer of silicone products, our product range covers many categories, from silicone tubing to kitchen silicone products, and we also offer custom services. Click to learn more!
