Mechanical and Viscoelastic Properties of Wrinkled Graphene Reinforced Polymer Nanocomposites - Effect of Interlayer Sliding within Graphene Sheets.
Mechanical and Viscoelastic Properties of Wrinkled Graphene Reinforced Polymer Nanocomposites - Effect of Interlayer Sliding within Graphene Sheets.
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DOI：
10.1016/j.carbon.2021.02.071
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发表时间：
2021-06-15
期刊：
影响因子：
10.9
通讯作者：
Meng Z
中科院分区：
文献类型：
--
作者：
Wang Y;Meng Z
多层石墨烯片材(MLGS)是一种很有前途的纳米增强材料，可以有效地提高聚合物基质的性能。尽管对MLGSS增强聚合物纳米复合材料的研究很多，但MLGSS中形成的皱纹对聚合物纳米复合材料的增强效果和粘弹性性能的影响尚不清楚。在这项研究中，我们基于先前开发的MLGS和聚甲基丙烯酸甲酯的粗晶模型，结合分子动力学模拟，系统地研究了具有不同石墨烯层数和不同褶皱构型的纳米复合材料。我们发现，随着波纹度的减小和层数的增加，纳米复合材料的弹性模量增加。有趣的是，我们观察到了某些起皱的MLGSS增强纳米复合材料在剪切变形过程中的突然应力下降。我们进一步对这些纳米复合材料进行了小幅度振荡剪切模拟，发现具有这些特定皱纹构型的纳米复合材料也表现出特别大的损耗角正切，表明能量耗散能力增强。这些行为归因于这些褶皱的MLGS之间的层间滑动被激活，因为它们的层间剪切强度确实低于用转向分子动力学技术测量的平坦的MLGS。我们的研究表明，聚合物纳米复合材料的粘弹性能和变形机制可以通过MLGS起皱工程进行调整。
Multilayer graphene sheets (MLGSs) are promising nano-reinforcements that can effectively enhance the properties of polymer matrices. Despite many studies on MLGSs-reinforced polymer nanocomposites, the effect of wrinkles formed in MLGSs on the reinforcement effect and the viscoelastic properties of polymer nanocomposites has remained unknown. In this study, building upon previously developed coarse-grained models of MLGSs and poly(methyl methacrylate) coupled with molecular dynamics simulations, we have systematically investigated nanocomposites with different numbers of graphene layers and various wrinkle configurations. We find that with decreasing degree of waviness and increasing numbers of layers, the elastic modulus of the nanocomposites increases. Interestingly, we observe a sudden stress drop during shear deformation of certain wrinkled MLGSs-reinforced nanocomposites. We further conduct small amplitude oscillatory shear simulations on these nanocomposites and find that the nanocomposites with these specific wrinkle configurations also show peculiarly large loss tangents, indicating an increasing capability of energy dissipation. These behaviors are attributed to the activation of the interlayer sliding among these wrinkled MLGSs, as their interlayer shear strengths are indeed lower than flat MLGSs measured by steered molecular dynamics technique. Our study demonstrates that the viscoelastic properties and deformation mechanisms of polymer nanocomposites can be tuned through MLGS wrinkle engineering.
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影响因子：
17.1
作者：
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DOI：
10.1088/0965-0393/17/1/015002
发表时间：
2009-01-01
影响因子：
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