Heterogeneous polymer degradation oxygen diffusion limited

The lifetime of many polymer products in use is limited by oxidative degradation. Exposed samples are usually non-uniformly oxidised. At the macroscopic level, the heterogeneities can result from oxygen-diffusion-limited effects. If the rate of oxygen consumption exceeds the rate of oxygen permeation, oxidation occurs in the surface layers, whereas the core remains practically unoxidised. The importance of this effect depends on several parameters. First, intrinsic parameters are linked to material geometry (e.g., sample thickness) coupled with the oxygen consumption rate, which depends on the reactivity of... 

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