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Silicone vs. Neoprene Rubber in Defense and Aerospace

What you need to know about silicone vs. Neoprene rubber for demanding applications.

Silicone and polychloroprene (also known as Neoprene) rubber resist ozone, oxygen, water and weather. They’re supplied as sheets and extrusions, which often are fabricated into seals, and are also molded into parts. These synthetic elastomers have many similar properties, but silicone and Neoprene rubber also have one important difference. Silicone has a broader temperature resistance which allows it to seal and insulate against extreme heat while remaining flexible at colder temperatures.

By understanding the comparative advantages and disadvantages of each type of elastomer, engineers can make the right choice during compound selection. Yet it’s also critical to consider material costs and availability. In addition to environmental and chemical resistance, buyers may need custom compounding and shorter lead times. Commodity rubber is fine for some applications, but aerospace and defense may need grades that meet specifications such as A-A-59588.

Environmental and Chemical Resistance

Silicone supports a wider range of temperatures and has better compression set, but Neoprene offers higher abrasion resistance and tensile strength. The table below describes some common material properties for each elastomer for comparing silicone vs. neoprene rubber.

Silicone Polychloroprene (Neoprene)
Temperature Range -100° to 450° F -40° C to 230° F (Dry Heat Only)
Compression Set Excellent Good
Weather Resistance Excellent Good
Abrasion Resistance Poor Good

Silicone and Neoprene resist oils and greases, but silicone is also recommended for elevated temperature applications. Neither elastomer can withstand hydrocarbon fuels such as gasoline or diesel. Neoprene rubber is a good choice for some refrigerants.

Industries and Applications

Polychloroprene (Neoprene) is used in fluid sealing, refrigeration sealing, and in industries such as automotive, mass transit, construction, and defense. Examples of Neoprene products include door and window seals, O-rings, washers, bearing pads, vibration mounts, shock absorbers, and marine gaskets. With its good physical toughness and mechanical strength, Neoprene offers a good balance of performance properties.

Silicone is used in door and window seals, weather seals, and in appliances and electronics. This synthetic rubber is also used in high voltage insulation, outdoor cable protection, HVAC drains, and fluid transfer. Silicone has excellent aging properties in sunlight. Industries that use silicone products include mass transit, food service, healthcare, retail, automotive, construction, and defense.

Special Considerations for Silicone vs. Neoprene Rubber

Silicone is in short supply globally, but that’s no reason to select the wrong material when you’re comparing silicone vs. Neoprene rubber. By partnering with the right supplier, you can get the right silicone, Neoprene, or other elastomer that you need. For example, VIP Rubber supplies a 30-durometer silicone that meets the demanding requirements of the A-A-59588 3B specification, which superseded ZZ-R-765.

For defense and aerospace manufacturers, the 3B standard is especially important because it’s one of only two A-A-59588 classes that require flex-fatigue resistance – a measure of an elastomer’s ability to withstand repeated flexing or bending. Unlike a commodity silicone, this specialized elastomer is superior. To learn more, contact Vip Rubber.