弹性体纳米复合材料Payne效应机理的分子动力学模拟与理论研究

Through molecular dynamics simulation, this project aims to discover the mechanism of the Payne effect in elastomer nanocomposites at the molecular level. To simulate much length and time scales, we adopt coarse-grained and atomistic models at the same time. Besides simulating the change of the storage modulus as a function of the strain amplitude, we characterize the micro-structural evolution with respect to the dynamic strain, such as the inter-particle distance and its distribution、chain size(the radii of gyration and end-to end distance)、chain conformation(the number and distribution of chain bridges formed by being adsorbed onto more than two particles at the same time)、particle-particle、particle-polymer and polymer-polymer total interaction energy. Moreover, we systematically explore the effects of the particle size、volume fraction、surface activity and chain length on the Payne effect. Lastly we hope to develop and put forward an theoretical model with high applicability, by incorporating the structural parameters as many as possible, to quantitatively explain and predict the Payne effect. The content of this project is one of the worthwhile and fundamentally theoretical subjects in elastomer science and technology, and the method to study the Payne effect through molecular dynamics simulation is not reported. The execution of this project will provide scientific basis and theoretical guidance to optimize the static and dynamic mechanical properties of elastomer nanocomposites used for automobile tires.

本项目拟采用分子动力学模拟，从分子水平上揭示弹性体纳米复合材料的Payne效应机理。为模拟跨尺度与跨时间，我们将粗粒度与全原子模型有机结合。在模拟体系储能模量随应变幅度变化的同时，表征其微观结构的动态演化行为：包括颗粒分布与间距、分子链尺寸(均方回转半径与均方末端距)、分子链构象(搭接在两个或两个以上颗粒而形成桥链的数目与分布)、颗粒—颗粒总的相互作用能、颗粒—分子链总的相互作用能与分子链—分子链总的相互作用能的变化，并系统考察炭黑与白炭黑的尺寸、填充分数、表面活性与分子链长对储能模量随应变幅度变化的影响，最后提出一个涵盖因素尽可能全面、普适度高的理论模型，对Payne效应进行定量解释与预测。本项目的研究内容是弹性体科学与工程中最为关注的根本性理论问题之一，采用分子动力学模拟的方法在国际上未见报道, 本项目的实施也将为优化轮胎用弹性体纳米复合材料的动静态力学性能提供科学依据与理论指导。

本项目采用分子动力学模拟，从分子水平上成功揭示了弹性体纳米复合材料的Payne效应机理。为模拟跨尺度与跨时间，我们将粗粒度与全原子模型有机结合。在模拟体系储能模量随应变幅度变化的同时，表征其微观结构的动态演化行为：包括颗粒分布与间距、分子链尺寸(均方回转半径与均方末端距)、分子链构象(搭接在两个或两个以上颗粒而形成桥链的数目与分布)、颗粒—颗粒总的相互作用能、颗粒—分子链总的相互作用能与分子链—分子链总的相互作用能的变化，并系统考察炭黑或白炭黑的尺寸、填充分数、表面活性与分子链长对储能模量随应变幅度变化的影响。在此基础上，我们成功的提出了一个涵盖因素尽可能全面、普适度高的理论模型，对Payne效应进行定量解释与预测。本项目的研究内容是弹性体科学与工程中最为关注的根本性理论问题之一，采用分子动力学模拟的方法在国际上未见报道, 本项目的研究成果将为优化轮胎用弹性体纳米复合材料的动静态力学性能提供科学依据与理论指导。