NBR vs. Silicone Rubber

Attribute	NBR	Silicone Rubber
Chemical Structure	Butadiene and Acrylonitrile	Silicon, Oxygen, Carbon, and Hydrogen
Temperature Range	-40°C to 120°C	-60°C to 230°C
Oil Resistance	Good	Excellent
Compression Set	Good	Excellent
Elasticity	High	High

Introduction

When it comes to choosing the right material for a specific application, engineers and designers often have to weigh the pros and cons of different options. Two popular choices for rubber materials are NBR (Nitrile Butadiene Rubber) and Silicone Rubber. Both materials have unique attributes that make them suitable for various applications, but they also have differences that can impact their performance in specific environments.

Chemical Composition

NBR is a synthetic rubber made from a copolymer of acrylonitrile and butadiene. This composition gives NBR excellent resistance to oil, fuel, and other chemicals, making it a popular choice for applications where exposure to harsh chemicals is a concern. On the other hand, Silicone Rubber is a synthetic elastomer made from silicon, oxygen, carbon, and hydrogen. Silicone Rubber has excellent resistance to extreme temperatures, making it a preferred choice for applications where high or low temperatures are a factor.

Physical Properties

One of the key differences between NBR and Silicone Rubber is their physical properties. NBR has a higher tensile strength and tear resistance compared to Silicone Rubber, making it a better choice for applications where durability and strength are important. On the other hand, Silicone Rubber has better flexibility and compression set resistance, making it ideal for applications where flexibility and resilience are key factors.

Temperature Resistance

As mentioned earlier, Silicone Rubber has excellent resistance to extreme temperatures, with a temperature range of -60°C to 230°C. This makes Silicone Rubber a popular choice for applications that require exposure to high or low temperatures. NBR, on the other hand, has a lower temperature range of -40°C to 108°C, making it less suitable for extreme temperature environments.

Chemical Resistance

One of the key advantages of NBR is its excellent resistance to oil, fuel, and other chemicals. This makes NBR a preferred choice for applications in the automotive and oil industries where exposure to harsh chemicals is common. Silicone Rubber, on the other hand, has poor resistance to oil and fuel, making it less suitable for applications where chemical resistance is a key factor.

Water Resistance

Both NBR and Silicone Rubber have good water resistance, but Silicone Rubber has better resistance to water and steam compared to NBR. This makes Silicone Rubber a preferred choice for applications where exposure to water or steam is a concern, such as in food processing or medical devices. NBR, on the other hand, may swell or degrade when exposed to water for extended periods.

Electrical Insulation

When it comes to electrical insulation properties, Silicone Rubber is the preferred choice due to its high dielectric strength and resistance to electrical arcing. Silicone Rubber is commonly used in electrical and electronic applications where insulation is critical. NBR, on the other hand, has lower electrical insulation properties compared to Silicone Rubber, making it less suitable for electrical applications.

Abrasion Resistance

NBR has excellent abrasion resistance, making it a preferred choice for applications where wear and tear are a concern. NBR is commonly used in seals, gaskets, and O-rings in industrial applications where abrasion resistance is important. Silicone Rubber, on the other hand, has lower abrasion resistance compared to NBR, making it less suitable for applications where resistance to wear is a key factor.

Conclusion

In conclusion, both NBR and Silicone Rubber have unique attributes that make them suitable for various applications. NBR is known for its excellent resistance to oil and chemicals, high tensile strength, and abrasion resistance, making it a preferred choice for applications in the automotive and industrial sectors. On the other hand, Silicone Rubber is preferred for its excellent temperature resistance, flexibility, and water resistance, making it ideal for applications in the food processing, medical, and electrical industries. Ultimately, the choice between NBR and Silicone Rubber will depend on the specific requirements of the application and the environmental conditions it will be exposed to.