  This study presents a coarse-grained molecular dynamics simulation model to
investigate the process of oxidative aging in polymers. The chemical aging
effect is attributed to the auto-oxidation mechanism, which is initiated by
radicals, leading to the chain scission and crosslinking of polymer chains. In
this study, we integrate a thermal oxidation kinetic model in the oxygen excess
regime into the Kremer-Grest model, thereby enabling a reactive coarse-grained
molecular dynamics simulation to capture the process of oxidative degradation.
Our simulation reveals that when the timescale of the characteristic reaction
step of oxidative degradation is shorter than the longest relaxation time of
polymer chains, the scission sites exhibit spatial heterogeneity. This
innovative simulation model possesses the potential to enhance our
comprehension of polymer aging phenomena, thus making noteworthy contributions
to the realm of polymer science and degradation chemistry.
