Graphene has emerged as one of the promising nanoscale components of polymer nanocomposites owing to its exceptional properties. The 2D graphene material, when distributed appropriately in the host polymer can significantly alter the load, electron, and phonon transfer behavior of the nanocomposites. The in-plane strong covalent bonds in graphene are accountable for these unique properties, whereas the weak van der Waals forces existing between the adjacent monolayer graphene planes are responsible for the re-stacking or agglomeration of layers. Hence, the most critical challenge in translating these properties in high-performance graphene polymer nanocomposite is to alleviate the agglomeration of graphene. This can be achieved by improving the distribution states of graphene in the matrix by; (1) enhancing the dispersion and (2) controlling the relative lattice orientation of graphene in substrates to create an alignment or orientation. Mitigating the agglomerates during the composite fabrication will significantly extend the benefits of graphene's inherent properties to the nanocomposite. In this review article, various methods for improving dispersion and orientation of graphene in polymer nanocomposites is elucidated. A decision flowchart on the choice of dispersion or orientation based on the properties is considered and the techniques to quantify and verify the same is deliberated. Furthermore, composites' performance in terms of mechanical, electronic, and thermal enhancements due to the molecular level dispersion or anisotropic orientation of graphene is discussed. This review provides a constructive guidance in the composite processing methods and to correlate the enhancement of properties with the distribution state of graphene in composites.

石墨烯由于其特殊的性质，已成为聚合物纳米复合材料的有前途的纳米级组分之一。二维石墨烯材料在主体聚合物中适当分布时，可以显着改变纳米复合材料的负载、电子和声子转移行为。石墨烯中的面内强共价键负责这些独特的性质，而相邻单层石墨烯平面之间存在的弱范德华力负责层的重新堆叠或团聚。因此，将这些特性转化为高性能石墨烯聚合物纳米复合材料的最关键挑战是减轻石墨烯的团聚。这可以通过改善基体中石墨烯的分布状态来实现：(1) 增强分散和 (2) 控制石墨烯在基板中的相对晶格取向以产生对齐或取向。在复合材料制造过程中减少团聚将显着扩展石墨烯固有特性对纳米复合材料的好处。在这篇评论文章中，阐述了改善石墨烯在聚合物纳米复合材料中的分散和取向的各种方法。考虑了基于特性选择分散或取向的决策流程图，并考虑了量化和验证相同的技术。此外，还讨论了由于石墨烯的分子级分散或各向异性取向导致的复合材料在机械、电子和热增强方面的性能。