Coupling between hydrolysis and mechanical relaxation in an ester‐based polyurethane network

Abstract

In this study, we first investigate the impact of a chain scission process due to hydrolysis on the relaxation behavior of an elastomer. We then explore the possible influence of a deformed state on the chemical reactions associated with hydrolysis. To perform the experiments coupling mechanical relaxation and hydrolysis, we select not only specific conditions such as the type of elastomer but also severe conditions such as immersions at high temperatures. Here, an ester‐based polyurethane network is chosen to easily hydrolyze the ester function, thus leading to a chain scission process. In addition, relaxation tests are performed in water at several temperatures (i.e., 40, 60, and 80 °C) to accelerate the hydrolysis rate. Results show that a deformed state does not accelerate the hydrolysis rate. However, a chain scission process clearly modifies the relaxation behavior. Finally, this behavior is modeled by coupling the chain scission kinetics with the relaxation time based on the Kohlrausch–Williams–Watts approach.