Wu Chao, Wu Ruidong, Tam Lik-Ho
School of Transportation Science and Engineering, Beihang University, 37 Xueyuan Road, Beijing 100191, People's Republic of China.
Nanotechnology. 2021 May 24;32(32). doi: 10.1088/1361-6528/abf458.
With the incorporation of carbon nanotubes (CNTs), CNT/polypropylene (PP) nanocomposites are found to possess enhanced mechanical properties, but the reinforcing effect is reduced at large added CNT weight percentages due to CNT aggregation. Optimizing the properties of a nanocomposite requires a fundamental understanding of the effects of CNT dispersion on the nanocomposite. In this work, coarse-grained molecular models of CNT/PP nanocomposites are constructed, which consist of randomly dispersed or aggregated CNT bundles. Our simulation results reveal that with randomly dispersed CNT bundles, the nanocomposite shows properties that continuously improve with increasing CNT contents due to the effective CNT/PP interface and the reinforcing effect of CNTs. By comparison, the nanocomposite with aggregated CNT clusters exhibits a decline in yield strength at CNT contents over 3 wt%, which results from a reduced CNT load-carrying capacity due to the formation of structural voids in the interfacial region. This study achieves anobservation of the structural void evolution of loaded nanocomposites, provides valuable insights into the effects of CNT dispersion on the mechanics of CNT/PP nanocomposites, and paves the way for optimizing the design of nanocomposites with superior mechanical properties by designing the CNT dispersion in the structure.
随着碳纳米管（CNTs）的加入，发现碳纳米管/聚丙烯（PP）纳米复合材料具有增强的机械性能，但由于碳纳米管的聚集，在较大的碳纳米管添加重量百分比下增强效果会降低。优化纳米复合材料的性能需要对碳纳米管分散对纳米复合材料的影响有基本的了解。在这项工作中，构建了碳纳米管/PP纳米复合材料的粗粒度分子模型，其由随机分散或聚集的碳纳米管束组成。我们的模拟结果表明，对于随机分散的碳纳米管束，由于有效的碳纳米管/PP界面和碳纳米管的增强作用，纳米复合材料的性能随着碳纳米管含量的增加而持续改善。相比之下，具有聚集碳纳米管簇的纳米复合材料在碳纳米管含量超过3 wt%时屈服强度下降，这是由于在界面区域形成结构空隙导致碳纳米管承载能力降低所致。本研究实现了对负载纳米复合材料结构空隙演变的观察，为碳纳米管分散对碳纳米管/PP纳米复合材料力学性能的影响提供了有价值的见解，并通过设计结构中的碳纳米管分散为优化具有优异机械性能的纳米复合材料设计铺平了道路。
