Abstract Previous experiments on the mechanics of graphene-based polymer nanocomposites report their mechanical properties far below theoretical predictions. A critical factor in this regard is the nature and strength of nanofiller/matrix interfacial bonding. Herein, beneficial effects of chemical functionalization on the interfacial mechanical properties of graphene-based polymer nanocomposites are investigated using complementary experiments and molecular dynamics (MD) simulations. We report that by tuning the extent and chemistry of the functionalized species, (approximately 10%), graphene-PMMA nanocomposites can achieve superior mechanical properties by improving the interfacial load transfer. Compared to pure PMMA, an increase of 46% in Young's modulus and 119% in energy absorbed per unit volume during fracture, respectively, were achieved for 10% functionalized nanocomposites. Such an increase in energy absorbed was caused by a transition in crack propagation mechanism from interfacial slippage to crack arresting behavior, owing to the enhanced interfacial bonding. MD simulations revealed that such a change in mechanism is caused by the formation of both hydrogen bond networks and physical entanglements at the interface. While the methodology can be applied for different nanocomposite systems, the present results may provide an avenue for more efficient design of graphene-based nanocomposite structures.

中文翻译：

---

通过调节化学官能化增韧石墨烯基聚合物纳米复合材料

摘要先前关于石墨烯基聚合物纳米复合材料力学的实验报告其力学性能远低于理论预测。这方面的一个关键因素是纳米填料/基质界面结合的性质和强度。在此，使用互补实验和分子动力学 (MD) 模拟研究化学官能化对石墨烯基聚合物纳米复合材料的界面机械性能的有益影响。我们报告说，通过调整功能化物种的范围和化学性质（约 10%），石墨烯-PMMA 纳米复合材料可以通过改善界面负载转移来实现优异的机械性能。与纯 PMMA 相比，断裂过程中单位体积的杨氏模量分别增加了 46% 和 119% 的能量吸收，实现了 10% 的功能化纳米复合材料。吸收能量的这种增加是由裂纹扩展机制从界面滑移到裂纹阻止行为的转变引起的，这是由于界面结合的增强。MD 模拟表明，这种机制的变化是由氢键网络和界面处物理纠缠的形成引起的。虽然该方法可以应用于不同的纳米复合材料系统，但目前的结果可能为更有效地设计基于石墨烯的纳米复合材料结构提供一条途径。MD 模拟表明，这种机制的变化是由氢键网络和界面处物理纠缠的形成引起的。虽然该方法可以应用于不同的纳米复合材料系统，但目前的结果可能为更有效地设计基于石墨烯的纳米复合材料结构提供一条途径。MD 模拟表明，这种机制的变化是由氢键网络和界面处物理纠缠的形成引起的。虽然该方法可以应用于不同的纳米复合材料系统，但目前的结果可能为更有效地设计基于石墨烯的纳米复合材料结构提供一条途径。