Abstract Observations in barrier tests on polymer composites with flake-like nanoparticles demonstrate one-step and two-step experimental dependencies of penetrant diffusivity on volume fraction of filler. Conventional models describe the one-step monotonic reduction in the effective diffusivity, but fail to predict the two-step decay. A model is developed for the effective diffusivity of polymer nanocomposites that takes into account clustering of nanoparticles induced by an increase in their content. An advantage of the model is that it (i) predicts both one-step and two-step experimental diagrams in an unified manner, and (ii) involves only two adjustable parameters with transparent physical meaning. The model is applied to the analysis of barrier properties of composites loaded with layered silicate clays, graphene, graphene oxide and reduced graphene oxide, boron nitride and molybdenum disulfide. Good agreement is shown between the experimental data and results of simulation. The influence of polymer matrices, types and chemical modifications of nanoparticles and preparation conditions on aggregation of filler is studied numerically.

中文翻译：

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聚合物纳米复合材料阻隔性能的微观力学模型

摘要 对具有片状纳米颗粒的聚合物复合材料进行阻隔测试的观察结果表明，渗透剂扩散率对填料体积分数的一步和两步实验依赖性。传统模型描述了有效扩散率的一步单调降低，但无法预测两步衰减。为聚合物纳米复合材料的有效扩散率开发了一个模型，该模型考虑了由其含量增加引起的纳米颗粒的聚集。该模型的一个优点是它（i）以统一的方式预测了一步和两步实验图，并且（ii）只涉及两个具有透明物理意义的可调参数。该模型应用于分析含有层状硅酸盐粘土、石墨烯、氧化石墨烯和还原氧化石墨烯、氮化硼和二硫化钼。实验数据和模拟结果之间显示出良好的一致性。数值研究了聚合物基质、纳米颗粒的类型和化学改性以及制备条件对填料聚集的影响。