Advances in exploring mechanistic variations in thermal aging of polymers

Abstract

More confident lifetime prediction of the performance of polymeric materials requires a better understanding of how temperature may not only accelerate aging but also introduce mechanistic variation in the degradation process itself. Such effects may occur in any high stress level environments that contain a thermal reaction component, i.e., thermal aging, UV, hydrolytic, and gamma initiated degradation. The underlying reactions that govern the degradation of a material at the low stress level environment may not be represented to the same degree under accelerated conditions. Additional chemical and physical reactions can be introduced under high stress level conditions leading to anomalies and complications for lifetime prediction. Sensitive oxidation rate measurements, monitoring the consumption of an antioxidant, or chemiluminescence based wear-out experiments can be suitable avenues to probe for variations in thermal degradation processes. Under dynamic temperature conditions, knowledge of the exact thermal history and the dominant thermal reaction component, as well as its activation energy, is needed to better establish mean degradation rates and understand "real" temperature contributions. © Springer Science+Business Media, LLC 2009.