Skip to content

Weathering Testing Standards for Polymers

Plastics Standards

Polymers come in an endless variety of physical properties, appearances, and durability often making them the first choice for specific applications in transportation, packaging, building materials, electronics, and many others.

Degradation of Polymers

All polymers, especially when used outdoors but also for indoor applications, undergo irreversible physical and chemical changes caused by ultraviolet (UV) radiation, heat, and moisture. UV radiation typically initiates photo-oxidation degradation pathways in the presence of oxygen. Furthermore, every polymer has a certain spectral sensitivity, often a range within the short wavelength UV, but also often including the long wavelength UV and the lower visible wavelength range.

The property changes caused by the effects of weathering can be:

  •   Yellowing especially of transparent/white polymers
  •   Color change
  •   Loss of physical strength
  •   Gloss loss caused by micro-cracks in the surface
  •   Brittleness
  •   Color fading of dyed/pigmented polymers

UV Stabilization

There are many ways to protect polymers against the damaging effects of UV radiation and the resulting photo-oxidative degradation. Determining the right stabilizer type and quantity inside a formulation is critical to all companies that manufacture masterbatches or processes polymers into components or products. Laboratory and natural weathering tests are the most important tools to understanding the weatherability of these polymers.

Select the Right Test Method

Plastics Standards Table

Over the years, the variety of xenon-arc standardized test methods for outdoor and indoor polymer applications has increased. The table lists 8 outdoor and 5 indoor test methods commonly used.”
from below to above table.

The question from most polymer manufacturers is: Which is the right test method for my product? The answer is easy when you have products for which a tailored standard has already been written. For example, for PVC window profiles, dental materials, indoor carpets and hard floors, or PV-module materials.

The answer is a little bit more difficult for other products. These other applications are typically tested using generic weathering standards such as ISO 4892-2 Method A/B, or ASTM G155 cycle 1. Without defined test durations, the question is often: how much faster are those laboratory test and how well do they reproduce the property changes caused by natural weathering (correlation)? The answer can be found in performing natural weathering benchmark studies.

More Information

The weathering testing of polymers is a vast subject that we have only briefly touched today. Please note that Atlas has posted further articles and resources on polymer testing on the Atlas website.

 •  Weathering testing standards for polymers
 •  Using SUNTEST to determine the service life extension of polymers through UV stabilizers
 •  Basics of polymer degradation in weathering

Listen to recorded online seminars:

 •  Photooxidation & stabilization mechanisms for polymers
Time scales in environmental aging of polymers