Effects of vacancy defects on the interfacial shear strength of carbon nanotube reinforced polymer composite.
Effects of vacancy defects on the interfacial shear strength of carbon nanotube reinforced polymer composite.
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空位缺陷对碳纳米管增强聚合物复合材料界面剪切强度的影响
DOI：
10.1166/jnn.2010.1879
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发表时间：
2010
影响因子：
--
通讯作者：
M. Nishikawa
中科院分区：
文献类型：
--
作者：
S. Chowdhury;T. Okabe;M. Nishikawa
我们通过分子动力学模拟研究了碳纳米管（CNT）中的空位缺陷（即缺失原子）对 CNT-聚乙烯复合材料界面剪切强度（ISS）的影响。在模拟中，结晶聚乙烯基体以六角形阵列排列，聚合物链平行于 CNT 轴。碳纳米管中的空位缺陷是通过从原始碳纳米管（即没有任何缺陷的碳纳米管）中去除相应的原子而引入的。考虑具有三种不同尺寸的三种空位缺陷模式。这里还考虑了两种类型的界面，即碳纳米管和基体之间有和没有交联。聚乙烯链用作 CNT 和基体之间的交联。布伦纳势用于 CNT 中的碳-碳相互作用，而聚合物则通过联合原子势进行建模。 CNT 和聚合物基体之间以及聚合物基体本身内部的非键合范德华相互作用通过 Lennard-Jones 势进行建模。为了确定 ISS，我们将 CNT 从聚合物基体中拉出，并根据 CNT-聚合物系统总势能的变化来估计 ISS。模拟结果表明，空位缺陷对ISS有显着影响。此外，模拟表明，在大尺寸空位缺陷的拉出过程中，CNT 会发生断裂，最终降低了补强效果。
We investigate the effects of the vacancy defects (i.e., missing atoms) in carbon nanotubes (CNTs) on the interfacial shear strength (ISS) of the CNT-polyethylene composite with the molecular dynamics simulation. In the simulation, the crystalline polyethylene matrix is set up in a hexagonal array with the polymer chains parallel to the CNT axis. Vacancy defects in the CNT are introduced by removing the corresponding atoms from the pristine CNT (i.e., CNT without any defect). Three patterns of vacancy defects with three different sizes are considered. Two types of interfaces, with and without cross-links between the CNT and the matrix are also considered here. Polyethylene chains are used as cross-links between the CNT and the matrix. The Brenner potential is used for the carbon-carbon interaction in the CNT, while the polymer is modeled by a united-atom potential. The nonbonded van der Waals interaction between the CNT and the polymer matrix and within the polymer matrix itself is modeled with the Lennard-Jones potential. To determine the ISS, we conduct the CNT pull-out from the polymer matrix and the ISS has been estimated with the change of total potential energy of the CNT-polymer system. The simulation results reveal that the vacancy defects significantly influence the ISS. Moreover, the simulation clarifies that CNT breakage occurs during the pull-out process for large size vacancy defect which ultimately reduces the reinforcement.