Depletion Mechanisms of Antioxidants in Polyethylene-Clay Nanocomposites

Drexel University, Philadelphia PA

Investigators

Abstract

Polymer clay nanocomposites appear poised to become an attractive new class of engineering materials. Polyethylene is the most widely used polymer in engineering products. Adding nanoclay to polyethylene can greatly enhance the mechanical properties; however, the effect on the long-term performance is less known. Polyethylene is susceptible to oxidation which is minimized by adding antioxidants. Once antioxidants are completely consumed, oxidation degradation begins and subsequently leads to material deterioration. The depletion mechanism of antioxidants in polyethylene nanoclay composites will be assessed based on thermo-oxidation in dry and wet environments. The non-oxidization behavior of antioxidants in the nanocomposite will be characterized by identifying their physical adsorption onto the surface of nanoclay as well as their hydrolysis sensitivity. The diffusion of oxygen into the nanocomposite and reaction with antioxidants will be determined and modeled to obtain the intrinsic oxidation rate constant. The critical microscopic properties that could serve as precursors for the onset of macroscopic property change will be established. Successful completion of this project will have broader impacts on engineering materials and will strengthen graduate and undergraduate education. By employing chemistry and materials testing approaches, this project will facilitate multidisciplinary collaboration and provide a platform for graduate and undergraduate students to work together in materials science and engineering disciplines. This project will also serve as a vehicle for introducing innovative new materials to civil engineering students. The research findings can be beneficial to many civil engineering sectors where polyethylene products are used as essential components of the system.