If you have ever left a rubber band outside overnight in the winter, you probably saw first-hand what cold temperatures can do to this compound. As Science ABC notes, when rubber is exposed to cold, the molecules don’t move past each other as readily, so the rubber band can become brittle and more prone to snapping.
While this phenomenon probably won’t impact you too much when it comes to rubber bands you use around the house, the impact of low temperatures on rubber and other sealing components can be critical in a number of industries. For instance, seals are used in aerospace, pharmaceutical/medical, oil and gas, food and dairy, and petrochemical applications; if the seals do not perform well under cold conditions, lives can be at risk.
With this in mind, let’s take a look at some of the facts surrounding cryogenics and low-temperature seals, including how to ensure that any seal or grommet needed in your industry will be able to withstand cold temperatures.
Seals Undergo Rigorous Testing
When rubber seals get extremely cold, they will also become hard and be less likely to change form, which can cause leaks; this tendency to leak will continue, even when the rubber warms back up. To avoid any low-temp failures in seals, a number of tests can be conducted on them to determine how the specific rubber compound will react to very cold temperatures. For instance, the brittleness test called ASTM D2137 is a standard test that will measure the ability of a material to withstand breaking when exposed to certain temperatures. The torsional stiffness ratio, or ASTM D1053, will measure how the compound does when twisted at different temperatures and the temperature retraction, ASTM D1329, test will determine the temperature that once-frozen rubber will go back to an elastic state. These tests, when they are all conducted on the same compound, will give a really extensive look at the seal and how it will do when exposed to cold. For instance, researchers might find that a certain material doesn’t snap when it is exposed to temperatures that hover in the -30 degrees Celsius range, but it might be so stiff, leaks will still occur.
Why Some Compounds Are Better Than Others
While Dartmouth notes that low temperatures will have the same effect on all rubber-like materials — turning it from very elastic to a more rigid state — there is a vast difference on how specific rubbers and rubber-like products do under extreme testing. More specifically, what the various aforementioned tests will typically reveal is that some materials are better for super-cold conditions than others. For instance, polyurethane has been shown to have a great deal of tensile strength, including withstanding temperatures of -22 degrees Fahrenheit. Silicone is also a strong elastomer, able to still perform in temps as low as -67 degrees F. Gum rubber has also been shown to have low-temperature resistance, as has a synthetic rubber called Viton.
Check Temperature Resistance Before Buying
For business owners who use seals, grommets and gaskets on a regular basis, it is crucial to purchase the correct seal for the job and temperature. For instance, Apple Rubber offers in-depth information about the different types of rubber grommets that they sell. They also have a guide on their site that includes specific temperature resistance information about their o-rings — including those made from Viton and many other compounds.
Knowledge Equals Power & Safety
Cold temperatures definitely have an impact on rubber. Fortunately, scientists are aware of this issue and use testing to determine which compounds do best under extreme conditions. By being aware of this phenomenon and where to purchase grommets, o-rings and gaskets that are designed for specific applications and temperatures, various industries will be as safe as possible.