This work is dedicated to the mechanism underlying the influence of the oxidation on the dynamic and static characteristics of ethylene-propylene-diene monomer (EPDM) copolymer. A molecular dynamics simulation was employed to provide an insight into the effects of oxidation on the micro and macroscopic properties, such as the density and self-diffusion, free volume, glass transition, and chain transition dynamics. The carbonyl product, the chain scission, and the crosslinking in the EPDM were considered. Self-coefficients and radial distribution function were analyzed to achieve the diffusion and the structure of the systems using a 10 ns produce run at an equilibrium (298 K). The temperature dependence of glass transition and the autocorrelation function for internal torsional rotation have been discussed for understanding the chain dynamics and flexibility after aging, such as the relaxation time and the activation energy. It turns out that the introduction of more carbonyl groups suppresses the internal rotation and the conformational transition of the chains, resulting in the decrease of diffusion and less flexibility due to the strong polar interaction. A system associated with short chains after chain scission possesses a low activation energy, indicating a more flexibility of the chains. Furthermore, the crosslinked structure contributes to the weak chain transition of EPDM (higher T_g) and the high modulus (harden). The different molecular dynamics could be derived from the interaction energy and the structures, such as polar and nonbonded interaction. Some aspects of the details of chain rotation are discussed in this paper.

这项工作致力于氧化对乙烯-丙烯-二烯单体（EPDM）共聚物的动态和静态特性的影响的潜在机理。使用分子动力学模拟可以深入了解氧化对微观和宏观特性的影响，例如密度和自扩散，自由体积，玻璃化转变和链转变动力学。考虑了EPDM中的羰基产物，断链和交联。对自系数和径向分布函数进行了分析，以实现扩散，并且使用10 ns的产品在平衡（298 K）下运行时，系统的结构得以实现。为了理解老化后的链动力学和柔韧性，例如弛豫时间和活化能，讨论了玻璃化转变的温度依赖性和内部扭转的自相关函数。事实证明，引入更多的羰基会抑制链的内部旋转和构象转变，由于强的极性相互作用，导致扩散减少，柔韧性降低。断链后与短链相关的系统具有较低的活化能，表明链的柔性更大。此外，交联结构有助于EPDM的弱链跃迁（更高 事实证明，引入更多的羰基会抑制链的内部旋转和构象转变，由于强的极性相互作用，导致扩散减少，柔韧性降低。断链后与短链相关的系统具有较低的活化能，表明链的柔性更大。此外，交联结构有助于EPDM的弱链跃迁（更高 事实证明，引入更多的羰基会抑制链的内部旋转和构象转变，由于强的极性相互作用，导致扩散减少，柔韧性降低。断链后与短链相关的系统具有较低的活化能，表明链的柔性更大。此外，交联结构有助于EPDM的弱链跃迁（更高T _g）和高模量（硬化）。不同的分子动力学可以从相互作用能和结构中得出，例如极性和非键相互作用。本文讨论了链旋转细节的某些方面。