Weathering Testing for Polymer Durability

Weathering failures rarely happen because of one factor alone. UV exposure, heat, moisture, humidity, thermal cycling, part design, material formulation, and end-use environment all influence how a polymer performs over time.

In this on-demand webinar, Americhem experts explain how accelerated weathering and outdoor exposure testing can help product teams identify potential failure modes earlier, compare material options, and make more confident durability decisions before commercialization.

Weathering Fundamentals | Q&A

Q: Do indoor products need weathering testing?

A: Yes, they do. Indoor products still experience UV and fluorescent lighting exposure, elevated temperatures, repeated cleaning or sterilization processes, and long-term storage conditions that affect performance. There are many test methods and specifications published specifically for indoor products.

Q: How much testing is needed?

A: It’s helpful to think of it less as “how much is enough” and more as “have we answered the question we’re trying to answer?” The amount of testing truly depends on the risk associated with the application. A decorative product likely needs significantly less testing than a building and construction product expected to perform for decades. The goal is to generate enough information to make confident development decisions without over-testing. There are three common approaches: testing until failure, testing to a specified radiant exposure, or testing for a defined duration. Some specifications even outline how long to weather a material, what criteria to measure, and the pass/fail requirements.

Q: When should I select Xenon Arc exposure vs. other UV exposure tests?

A: Xenon Arc testing is often selected when a broad-spectrum light source that more closely simulates natural sunlight is desired, particularly for applications exposed to outdoor environments. Fluorescent UV testing is often used when UV degradation is the primary concern and a more targeted, accelerated exposure is appropriate. The best choice depends on the application, expected service environment, material type, and the failure mechanisms being evaluated.

Q: Does gloss change indicate material degradation?

A: Yes, gloss change can be an indicator of material degradation. Weathering can alter a material’s surface through oxidation, roughening, microcracking, or other degradation mechanisms, resulting in gloss loss. However, the significance of gloss change depends on the application. In some cases, it may be primarily an aesthetic concern, while in others it can signal broader surface degradation that may warrant further evaluation.

Q: Do dark colors weather faster?

A: Not necessarily, but darker colors often absorb more heat, which can introduce additional thermal stress. Performance depends on the entire formulation, not just the color. You can have a dark color, but if the formulation as a whole is robust, you’ll be better positioned for long-term performance.

Q: How significantly does weathering affect the mechanical properties of polymers?

A: There are a few polymers that are inherently UV stable, but most are not. Light energy interacts with the polymer chains. Imagine the molecules are linked by springs. When light hits them, those springs begin to vibrate back and forth. Over time, that vibration overcomes the bond strength and begins breaking the polymer chains down. That’s why a stabilization mechanism is needed to either absorb or convert the light energy.

Download the Weathering Q&A Guide