Prediction of Long-Term Behavior of Korean HDPE Geomembranes

Oxidation is generally recognized as the key degradation mechanism regarding the long-term durability of high density polyethylene (HDPE) geomembranes. For protection against oxidation during its service lifetime, antioxidants are added to the formulation. In this study, a comparison of long-term behavior between the oxidative properties of two HDPE resins and two types of compounded HDPE geomembrane sheets (manufactured by flat die and circular die) are investigated. These four different materials were subjected to air oven aging, UV exposure, and buffer solution aging. Before and after exposure, specimens were evaluated for density, melt index (MI), carbon black content (CBC), standard oxidative induction time (STD-OIT), and high pressure oxidative induction time (HP-OIT). In addition, each set of incubations was maintained at three different temperatures so that the set of results could be subsequently used to calculate predicted lifetime using the Arrhenius equation.