基于聚乙烯/蒙脱土纳米复合材料微观结构的力学性能模拟  

Simulation of mechanical properties based on microstructure in polyethylene/montmorillonite nanocomposites

作　　者：李丽丽[1,2] 张晓虹[1] 王玉龙[1,2] 国家辉[1] 张双[1] 

机构地区：[1]哈尔滨理工大学电气与电子工程学院,工程电介质及其应用教育部重点实验室,哈尔滨150080 [2]哈尔滨理工大学荣成学院,荣成264300

出　　处：《物理学报》2016年第19期207-218,共12页Acta Physica Sinica

基　　金：国家重点基础研究发展计划(批准号:2012CB723308);国家自然科学基金(批准号:51077029,51577045)资助的课题~~

摘　　要：模拟分子的结构与行为有助于更深刻地分析聚乙烯/蒙脱土(PE/MMT)纳米复合材料力学性能变化的微观机理.为此,以分子动力学为依据,利用Materials studio构建聚乙烯/蒙脱土纳米复合材料模型.在普适力场作用下,通过X射线衍射、径向分布函数以及相互作用能分别对纳米复合材料和纳米蒙脱土的微观结构和性能进行分析.仿真结果表明:有机化处理使蒙脱土的层间距增大79%;在蒙脱土质量分数为4.0 wt%时,PE/MMT纳米复合材料中存在明显的氢键作用,聚乙烯分子和蒙脱土片层间的相互作用能高达-390 kcal/mol,界面作用得到明显提高,最终形成稳定的材料结构,同时力学性能相比纯聚乙烯材料也得到改善,其中杨氏模量、体积模量以及剪切模量分别提高38%,21%和40%.分子模拟结果与实验实测结果相符,并验证了有机化蒙脱土改性聚乙烯绝缘材料会产生氢键作用.In order to explore the microscopic mechanism of mechanical properties in polyethylene/montmorillonite（PE/MMT）nanocomposite material, the molecular model and the molecule structure are simulated by simulation software, and the mechanisms of various complex phenomena of mechanical properties in PE/MMT nanocomposite material can be understood more in depth in the paper. To achieve this, the molecular model is developed under 423 K based on the molecular dynamics method and using the modules of Amorphous Cell as well, Forcite Tools and Reflex in the simulation software material studio includes polyethylene model, montmorillonite models without organization, organic montmorillonite model, and PE/MMT nanocomposites model. Then, microstructure and mechanical properties of PE/MMT nanocomposite material are analyzed by X-ray diffraction, radial distribution function and interaction energy test under universal force field, respectively. Some important findings emerge from the simulation results. First, after the molecular dynamic process of canonical ensemble（NVT） and constant-pressure, constant-temperature ensemble（NPT）, the fluctuations in temperature and energy of polyethylene, montmorillonite without organization, organic montmorillonite, and PE/MMT nanocomposite material are all less than 5%. This implies that the low energy state is occupied and steady structures are formed in PE/MMT nanocomposite material. Second, the inter-layer spacing of organic montmorillonite is expanded to 20 ？ due to cations of 18 alkyl three methyl ammonium chloride, which is increased by 79% compared with that of montmorillonite without organization. Meantime, the expansibility of PE/MMT nanocomposite material is obvious, and the density and volume of PE/MMT nanocomposite material are improved by-32% and 393% respectively, compared with those of organic montmorillonite. Third, when the mass fraction of organic montmorillonite reaches 4.0 wt%, the hydrogen bonding interaction obviously exists in PE/MMT nanocomposite material,

关 键 词：聚乙烯/蒙脱土纳米复合材料 微观结构 力学性能 

分 类 号：TB332[一般工业技术—材料科学与工程]