Thermal degradation of composites and thermoset materials under oxidative conditions depends on oxygen permeation behavior and local oxidation rates. Both parameters are required to predict spatially dependent polymer degradation with diffusion limited oxidation models. This presentation will review the acquisition of oxidation rates for epoxy materials and then focus on the optimization of experimental approaches and data extraction approaches, which are applied to characterize thin films of low permeable polymers to derive the required permeability data. The competition between oxygen permeation and reactive loss determines the evolution of degradation depth profiles with temperature. Two different epoxy thermosets are compared in their degradation features, in terms of the temperature dependence of oxidation rates, permeability, oxidative depth based on DLO models, experimentally observed discoloration, carbonyl profiles by IR spectroscopy, and the thickness of Total Oxidized Layer (TOL) based on theoretical degradation kinetic models. Evidence has been obtained that the ingress of thermo-oxidative damage is material specific for behavior linked to Tg, and that any TOL evaluation of composites under high temperature may not necessarily reflect a single oxidative equilibrium process.<br/><br/>Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy’s National Nuclear Security Administration under Contract DE-AC04-94AL85000.

Oxygen permeation and thermoset degradation with temperature

249th National Meeting (2015)

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