Coarse-Grained Molecular Dynamics Simulations of Oxidative Aging and Stabilization in Polymer Melts with Primary Antioxidants: Effects of Antioxidant Concentration and Molecular Architecture

TL;DR

This study uses coarse-grained molecular dynamics simulations to explore how antioxidant molecular architecture and concentration influence oxidative aging in polymer melts, providing detailed insights into stabilization mechanisms at the micro- to meso-scale.

Contribution

It introduces an extended simulation framework that explicitly models antioxidant molecules and their effects on oxidation kinetics and spatial heterogeneity in polymers.

Findings

Antioxidant molecular architecture significantly affects oxidation rates.

Higher antioxidant concentration reduces oxidative aging heterogeneity.

Simulation results align with experimental observations of stabilization effects.

Abstract

Industrial polymeric materials often rely on antioxidants to achieve long-term reliability. Previous studies have frequently discussed the stabilization effect in the presence of macroscopic additive migration. However, the micro- to meso-scale coupling between polymer dynamics and antioxidant molecular dynamics remains insufficiently understood. In this study, we extend a polymer dynamics simulation framework that can account for oxidative aging. We also update the model so that it can explicitly incorporate antioxidant molecules into the simulation. As a result, the framework enables us to quantify how molecular architecture of antioxidants affects oxidation kinetics, which has previously been inferred only indirectly from apparent changes in reaction rates. It also allows us to evaluate the effects of antioxidant concentration and molecular architecture on the spatial heterogeneity of oxidative aging.