Liquid crystal (LC) monomer with Schiff base-grafted functionalized GO (M2-g-GO) sheets was successfully prepared to enhance the dispersion and interfacial interaction between additives (M2-g-GO) and the epoxy matrix (E-51), resulting in the enhancement of thermal and mechanical performances of epoxy nanocomposites. The structures and performances of neat epoxy, GO/epoxy nanocomposite, and M2-g-GO/epoxy nanocomposites were characterized by a few analytical tests, such as Fourier transform infrared spectra, X-ray diffraction, scanning electron microscopy, dynamic mechanical analyzer, differential scanning calorimetry, and thermogravimetric analysis. Meanwhile, the polarized optical microscope test displayed LC monomer with Schiff base-grafted GO has been successfully synthesized. The T g and thermal performance of M2-g-GO/epoxy nanocomposites were distinctly promoted compared with those of the neat epoxy and GO/epoxy nanocomposite. Meanwhile, mechanical tests demonstrate the M2-g-GO/epoxy nanocomposites possess greater impact strength, flexural strength, and flexural modulus than those of the neat epoxy and GO/epoxy nanocomposite. It is also worth mentioning that the flexural strength with the adding content of 3 wt% increased by 62.1%, and the flexural modulus with the adding content of 3 wt% increased by 19.1%. Moreover, T d1% of M2-g-GO/epoxy nanocomposites were all higher than the neat epoxy (170 °C), and the T d5% of epoxy composites were around 385 °C, which were nearly 15 °C higher than that of neat epoxy. Meanwhile, the char yield of M2-g-GO/epoxy nanocomposites at 650 °C is 1.4% higher than that of 3 wt% GO/epoxy nanocomposites. Hence, the M2-g-GO exhibits predominant feasibility as effective increased thermal and toughness additives for leading to the enhancement of thermal and mechanical performances of nanocomposites.

中文翻译：

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席夫碱液晶单体接枝氧化石墨烯环氧纳米复合材料的热力学和力学性能增强

成功制备了具有 Schiff 碱接枝功能化 GO (M2-g-GO) 片的液晶 (LC) 单体，以增强添加剂 (M2-g-GO) 与环氧树脂基体 (E-51) 之间的分散和界面相互作用，从而提高环氧树脂纳米复合材料的热性能和机械性能。纯环氧树脂、GO/环氧树脂纳米复合材料和 M2-g-GO/环氧树脂纳米复合材料的结构和性能通过一些分析测试进行表征，如傅里叶变换红外光谱、X 射线衍射、扫描电子显微镜、动态力学分析仪、差示扫描量热法和热重分析。同时，偏光显微镜测试显示，已成功合成了带有 Schiff 碱接枝 GO 的 LC 单体。与纯环氧树脂和 GO/环氧树脂纳米复合材料相比，M2-g-GO/环氧树脂纳米复合材料的 Tg 和热性能明显提高。同时，机械测试表明 M2-g-GO/环氧树脂纳米复合材料比纯环氧树脂和 GO/环氧树脂纳米复合材料具有更高的冲击强度、弯曲强度和弯曲模量。还值得一提的是，添加量为3 wt%时弯曲强度增加了62.1%，添加量为3 wt%时弯曲模量增加了19.1%。此外，M2-g-GO/环氧树脂纳米复合材料的T d1% 均高于纯环氧树脂（170 °C），环氧树脂复合材料的T d5% 约为385 °C，比纯环氧树脂高近15 °C纯环氧树脂。同时，M2-g-GO/环氧树脂纳米复合材料在 650°C 的炭产率为 1。比 3 wt% GO/环氧树脂纳米复合材料高 4%。因此，M2-g-GO 作为有效增加的热和韧性添加剂表现出主要的可行性，用于提高纳米复合材料的热和机械性能。