In the weather testing of materials and products we intentionally focus on the three main weather factors. Heat, light, and moisture and their cycles are typically the most important for polymer degradation. Additionally, we also pay attention to key secondary stress factors such as atmospheric pollutants, agricultural chemicals, cleaning agents, and biological/microbiological agents.
However, one often neglected area is service use stresses; that is, stresses, usually physical in nature, that can hasten the effects of natural weathering or act as stress concentration points for damage.
