纳米颗粒界面性质及其分布对热塑性硫化胶相态结构的影响

Thermoplastic vulcanizates are a class of reusable "green" elastomer materials. However, most rubber-plastic blends have poor compatibility, phase structure is unstable, and material properties are difficult to meet practical requirements. The addition of nanoparticles can improve the interfacial structure of the blend and improve the material properties, but the addition of nanoparticles does not always achieve the desired results. In this project, we intend to use classical density functional theory, combined with other statistical mechanics methods and molecular dynamics simulation, to systematically study the effects of different kind, size, content and activity of nanoparticles on the phase structure of thermoplastic vulcanizate during dynamic vulcanization. It reveals the relationship between the microstructure and macroscopic properties of thermoplastic vulcanizate nanocomposites, and clarifies the mechanism of phase separation of thermoplastic vulcanizate induced by nanoparticles. On this basis, a theoretical model of interface structure which can reasonably and accurately describe nanoparticle/rubber/plastic three phases during blending process is developed. Building physical-chemical methods to realize the regulation of microstructure of rubber and plastic blending materials can provide a scientific basis and theoretical guidance for the preparation of high performance thermoplastic vulcanizate nanocomposites.

热塑性硫化胶是一类可重复利用的“绿色”弹性体材料，然而大部分的橡塑共混物相容性较差，相态结构不稳定，材料性能很难满足实际要求。添加纳米颗粒可以改善共混物的界面结构，提高材料性能，但是纳米颗粒的加入并不总是能够达到预期的效果。本项目拟采用经典密度泛函理论，结合其它统计力学方法和分子动力学模拟，从分子尺度上系统研究了不同种类、尺寸、浓度、性质的纳米颗粒对热塑性硫化胶相态结构的影响，揭示了热塑性硫化胶纳米复合材料微观结构和宏观性质的关系，阐明了纳米颗粒诱导的热塑性硫化胶相分离机理。在此基础上，发展出一个能合理准确描述共混过程中纳米颗粒/橡胶/塑料三相的界面结构理论模型，建立有效调控橡塑共混材料微观结构的物理化学方法，为制备高性能的热塑性硫化胶纳米复合材料提供科学依据和理论指导。

热塑性硫化胶纳米复合材料的最终性能不仅依赖于材料组分本身的特性，而且在很大程度上依赖于复合材料的界面结构和相形态。本项目利用经典密度泛函理论在研究界面结构调控及有机-无机复合行为的优势，结合分子动力学模拟，对纳米颗粒诱导的热塑性硫化胶相态结构变化进行了系统研究。通过结合PRISM理论和Koyama模型构建了纳米颗粒-热塑性硫化胶的三维界面结构模型，探明了聚合物链结构对颗粒选择性分布的影响机制，结合实验给出了接枝共聚物在界面的增容效果及对相态结构的影响关系，揭示了动态硫化过程中加工条件对纳米颗粒分布的调控机制，明晰了颗粒分布状态与橡塑共混物相态结构的热力学和动力学耦合机制。通过本项目的研究，有望为制备具有精细相态结构的热塑性硫化胶纳米复合材料提供理论指导。