What is Outgassing?

Did you know that there is a scientific explanation for the new car smell? 

When you drive off in your new car, you’re subjecting many of that car’s components to heat and pressure changes for the first time. In response to these changes, the vinyls, polyesters, and other materials used to make parts of the car like the upholstery and dashboard release organic compound gasses that had been trapped inside them. Those gasses are your new car smell.

This is the process known as outgassing, and though it’s common and natural, it can also be a big problem, especially for sensitive products and environments. It’s even one of the biggest concerns for NASA when they’re considering how to make their spacecraft! 

This is what you should know about outgassing, including how it happens, why it can be an issue, and how you can understand and control it. 

What is outgassing?

Outgassing is a process in which non-metallic components such as polymers, rubbers, adhesives, or epoxies release gas vapors that had been dissolved, trapped, frozen, or otherwise absorbed into them at some prior time. 

Outgassing is a normal and natural phenomenon, but it can be dangerous in some circumstances — especially when it happens in sensitive environments like vacuums or inside of delicate equipment. 

How does outgassing happen?

Outgassing happens as a consequence of the outgassing component undergoing a phase transition into a gas (from either a solid or a liquid) in response to a change in environment. As the component transforms into a gas, the other gasses trapped inside it are freed as vapors and can leak out into the surrounding environment.

Outgassing components most commonly undergo a phase transition in response to heat, but it can also happen in response to low temperatures, pressure changes (vacuums), or a combination of these factors. Experts have to carefully test components that will be subjected to environments that could trigger outgassing before they can use them for product manufacturing.

Why is outgassing a problem?

When outgassing occurs, the transition component can release potentially volatile organic vapors into an otherwise controlled environment. As these vapors condense back into liquid, they can interact with sensitive surrounding equipment in ways that can compromise their ability to function properly. In some cases, outgassing-induced malfunctions can even lead to dangerous product malfunction.

For example, outgassing can be a major problem for computer hard drives. If an adhesive used in the manufacturing of a hard drive outgasses and releases plasticizers or other low molecular weight materials, these materials could re-form on areas of the hard drive where they could cause shorts, crashes, and other malfunctions. 

How can experts prevent outgassing?

In most situations, manufacturing experts will attempt to prevent outgassing by making sure the materials they’re using to create their products won’t undergo a phase transition when exposed to the environments they’ll be used in. This will ensure that the components they use won’t release any vapors that could threaten other components.

In situations where the components in question must undergo a gaseous phase transition, manufacturers won’t prevent outgassing itself. Instead, they’ll simply want to make sure the vapors that the components release during their natural outgassing process aren’t going to be dangerous for the surrounding environment. 

Before they can safely use a non-metallic component in their manufacturing process, experts have to learn when and how that component outgasses and what kind of vapors it releases when it does. They get this information using professional outgassing testing.  

What is outgassing testing?

Outgassing testing refers to a class of scientific testing techniques used to evaluate a component’s outgassing properties and therefore understand the potential risks it could pose to a product or environment. 

Different outgassing techniques can determine when and how a component will outgas, what kind of vapors it will release, how these vapors could affect their surrounding environment, and more. 

How does outgassing testing work?

Innovatech uses two types of outgassing testing: static and dynamic headspace analysis. Both of these techniques are extended versions of gas chromatography with mass spectroscopy, so they are sometimes known as headspace GC/MS analysis.

Static headspace analysis

In static headspace analysis, experts place a solid or liquid sample of the component into a sealed vial. They heat this vial to a specific, preset temperature. If any outgassing occurs at this temperature, the volatile vapors released from the sample escape into a sealed (or static) “headspace” at the top of the vial.  

When it’s full, experts inject the contents of the headspace into a gas chromatograph. As the volatile components pass through the gas chromatograph, it separates them based on size and polarity. 

Finally, the separated gasses reach a mass selective detector that identifies each gas in turn, showing experts exactly what the sample released as a result of outgassing.

Static headspace analysis works best for analyzing volatile outgassed components, such as residual solvents or low molecular weight additives. 

Dynamic headspace analysis

Dynamic headspace analysis uses a purge and trap method. Experts place a solid or liquid sample of the component in a vessel that has already been heated. Then, they flush (or “purge”) the heated vessel with a special gas. 

As this gas flows out of the vessel, it carries any outgassed vapors the component released with it through a sorbent material. This sorbent material collects the outgassed components while allowing the purging gas through. After they’re collected, the experts flush the outgassed vapors out of the sorbent material into a GC/MS column for analysis. 

From here, the analysis happens the same way as it does for static headspace analysis: GC/MS separates the outgassed components based on size and polarity and then uses a mass selective detector to identify them. 

Dynamic headspace analysis works best for testing heavy molecular weight materials such as plasticizers. It’s also more sensitive than static headspace analysis and can identify substances as small as a nanogram per gram. 

How can I have my products tested for outgassing? 

If you think your components or products need outgassing testing, the experts at Innovatech are ready to help. Get in touch with us today and our pros will determine what kind of outgassing testing you need and how to best administer it.