目的 旨在利用分子动力学模拟方法，探究聚氯乙烯(PVC)接枝改性与增塑剂邻苯二甲酸二辛酯(DOP)共混的协同效应，为开发兼具优异增塑性和安全性的PVC材料提供理论依据和设计指导。方法 构建接枝改性的PVC元胞模型，计算模型体系的溶解度参数、玻璃化转变温度(Tg)、力学性能、相互作用能(Einter)、均方位移(MSD)以及径向分布函数(RDF)等关键参数，揭示接枝改性与DOP对PVC性能的协同影响机制。结果 接枝改性可有效降低PVC的Tg，其与DOP共混体系的Tg会进一步降低;接枝改性导致PVC主链间Einter降低，而接枝物的引入能显著提升PVC链间的Einter，保障材料力学性能的稳定性;接枝改性与DOP的协同作用显著提高了PVC的MSD，表明体系可塑性增强;RDF分析进一步证实，接枝改性和DOP共混削弱了PVC链间Cl与H的相互作用。结论 接枝改性与DOP的协同作用可有效调控PVC的可塑性。

The work aims to explore the synergistic effect of graft modification and the blending of plasticizer dioctyl phthalate (DOP) on polyvinyl chloride (PVC) by molecular dynamics simulation methods, providing theoretical basis and design guidance for the development of PVC materials with excellent plasticity and safety. A cell model of graft-modified PVC was constructed, and key parameters such as the solubility parameter, glass transition temperature (Tg), mechanical properties, intermolecular interaction energy (Einter), mean square displacement (MSD), and radial distribution function (RDF) of the model system were calculated to reveal the synergistic effect mechanism of graft modification and DOP on the performance of PVC. Graft modification could effectively reduce the Tg of PVC, and the Tg of the graft-modified PVC and DOP blend system was further reduced. Graft modification led to a decrease in Einter between PVC main chains, while the introduction of grafts could significantly increase Einter between PVC chains, ensuring the stability of mechanical properties of the material. The synergistic effect of graft modification and DOP significantly increased the MSD of PVC, indicating enhanced plasticity of the system. RDF analysis further confirmed that graft modification and DOP blending weakened the interaction between Cl and H in PVC chains. The synergistic effect of graft modification and DOP can effectively regulate the plasticity of PVC.