The improvement of Mode I fracture toughness of epoxy by the addition of single-walled carbon nanotubes (SWCNTs) is considered. To prepare nanocomposites, chemical-vapor-deposition-grown SWCNTs noncovalently functionalized with an ethoxylated alcohol was used as the additive and a diglycidyl ether of bisphenol-A-based epoxy as the matrix material. The SWCNTs were dispersed in the epoxy matrix via a mechanical stirrer and a 3-roll mill. The effect of their concentration (0.0125, 0.025, 0.05, 0.1, 0.3, and 0.5 wt.%) on the mechanical properties of the nanocomposites was investigated, and the optimum concentration was determined. Mode I fracture toughness (single-edge-notch 3-point bending) and tensile tests were carried out on neat epoxy and SWCNT-reinforced epoxy nanocomposites. The fractured surfaces of fracture toughness and tensile test specimens were examined by the SEM to reveal the effect of SWCNTs on their failure modes.

中文翻译：

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单壁碳纳米管 (SWCNT) 浓度对环氧树脂基体机械和流变行为的影响

考虑通过添加单壁碳纳米管 (SWCNT) 来提高环氧树脂的 I 型断裂韧性。为了制备纳米复合材料，使用乙氧基化醇非共价官能化的化学气相沉积生长的 SWCNT 作为添加剂，使用双酚 A 基环氧树脂的二缩水甘油醚作为基质材料。单壁碳纳米管通过机械搅拌器和三辊磨分散在环氧树脂基体中。研究了它们的浓度（0.0125、0.025、0.05、0.1、0.3 和 0.5 wt.%）对纳米复合材料力学性能的影响，并确定了最佳浓度。对纯环氧树脂和 SWCNT 增强的环氧树脂纳米复合材料进行 I 型断裂韧性（单边缺口 3 点弯曲）和拉伸试验。