Abstract Two-dimensional carbon nitride (C3N) is a promising alternative to graphene (GN) as the reinforcement in epoxy composites, yet the complicated interfacial interactions have not been fully understood, which restricts the application of using C3N for enhancing the mechanical properties of thermosetting polymers. To explore its functionality, we undertake this work aims to overcome the obstacles and uncover the interfacial interaction mechanism between C3N and epoxy chains through density function theory (DFT) and molecular dynamics (MD) simulations. We discover, for the first time, that C3N sheet exhibits outstanding performances on improving the thermal-mechanical properties of epoxy composites. The Young’s modulus and glass transition temperature of C3N reinforced epoxy are 20% and 26 K (7%) larger than that of GN filled epoxy, respectively. Our findings conclude that the interfacial interaction mechanisms behind the superlative thermal-mechanical properties are: (1) the C3N sheet exhibits a better adhesion with aromatic rings of epoxy chains, which is attributed to preferred parallel alignment of aromatic rings and C3N surface, and (2) the C3N sheet induces a higher capacity of hydrogen bonding at the interface, leading to better load transfer. The superior reinforcing efficiency of C3N over GN opens extensive applications of it in the next-generation thermomechanical systems.

中文翻译：

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从原子层面理解氮化碳增强环氧树脂复合材料的界面相互作用特征

摘要 二维氮化碳 (C3N) 是石墨烯 (GN) 的一种有前途的替代品作为环氧树脂复合材料的增强材料，但复杂的界面相互作用尚未完全清楚，这限制了使用 C3N 增强热固性材料力学性能的应用。聚合物。为了探索其功能，我们开展这项工作旨在通过密度函数理论 (DFT) 和分子动力学 (MD) 模拟克服障碍并揭示 C3N 与环氧基链之间的界面相互作用机制。我们首次发现 C3N 片材在改善环氧树脂复合材料的热机械性能方面表现出出色的性能。C3N 增强环氧树脂的杨氏模量和玻璃化转变温度比 GN 填充环氧树脂大 20% 和 26 K (7%)，分别。我们的研究结果得出结论，优异的热机械性能背后的界面相互作用机制是：（1）C3N 片与环氧链的芳环表现出更好的粘合性，这归因于芳环和 C3N 表面的优先平行排列，以及（ 2) C3N 片在界面处诱导更高的氢键容量，从而导致更好的负载转移。C3N 优于 GN 的增强效率开启了它在下一代热机械系统中的广泛应用。(2) C3N 片在界面处诱导更高的氢键容量，导致更好的负载转移。C3N 优于 GN 的增强效率开启了它在下一代热机械系统中的广泛应用。(2) C3N 片在界面处诱导更高的氢键容量，导致更好的负载转移。C3N 优于 GN 的增强效率开启了它在下一代热机械系统中的广泛应用。