Abstract The reinforcement efficiency of graphene in a nanocomposite relies on the size, morphology, defects and agglomeration of flakes. However, the characterisation is usually undertaken only for the raw materials and any changes that take place during processing are not taken into consideration. In this work, epoxy nanocomposites reinforced by graphite nanoplatelet (GNP) were prepared and nano-scale X-ray computed tomography was used to visualize the geometry, morphology and defects of the flakes, as well as the three dimensional agglomerates that are normally difficult to characterise by other techniques. In combination with micromechanical analysis, the taxonomy of the nanoplatelets is shown to be of great importance in controlling the mechanical properties of nanocomposites, and this has been shown to explain the deviations of the predictions of micromechanical models from the measured values. Particularly, it is shown that taking single average values of flake size may not be appropriate and the entire distribution of flake size need to be taken into consideration. Furthermore, it is shown that the Young's modulus of a nanocomposite is controlled principally by a small number of large flakes and that volume average distributions of flake size are more appropriate to use rather than number average ones.

中文翻译：

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石墨纳米片的分类和纳米复合材料加工的影响

摘要 石墨烯在纳米复合材料中的增强效率取决于薄片的尺寸、形态、缺陷和团聚。但是，通常仅对原材料进行表征，不考虑加工过程中发生的任何变化。在这项工作中，制备了由石墨纳米片 (GNP) 增强的环氧树脂纳米复合材料，并使用纳米级 X 射线计算机断层扫描来可视化薄片的几何形状、形态和缺陷，以及通常难以识别的三维团聚体。用其他技术表征。结合微观力学分析，纳米片的分类在控制纳米复合材料的力学性能方面具有重要意义，这已被证明可以解释微机械模型的预测与测量值的偏差。特别是，结果表明，取片状尺寸的单一平均值可能不合适，需要考虑片状尺寸的整体分布。此外，表明纳米复合材料的杨氏模量主要由少量大薄片控制，薄片尺寸的体积平均分布比数均分布更适合使用。