Epoxy resin as a thermoset polymer is vulnerable to creep loading even at room temperature due to its viscoelastic nature. This study investigated the effect of reinforcing epoxy resin with different functionalized multi-walled carbon nanotubes (MWCNT) contents on the creep response and post-creep residual tensile properties of nanocomposites. The creep tests were performed on the nanocomposite specimens containing different filler contents and the neat epoxy specimen at 40°C under a constant load level of 200 N. It was found that the nanocomposites containing 0.3 wt% MWCNTs experienced 29.6%, 69.1%, and 74.1% decreases in the elastic strain, creep strain, and steady-state creep strain rate, respectively, compared to the neat epoxy. Furthermore, the tensile strength and stiffness of the neat epoxy and nanocomposite specimens were evaluated before and after a partial creep test (at a load level of 200 N for 150 min) by conducting tensile tests. The nanocomposites containing 0.3 wt% MWCNTs demonstrated considerable improvements of 35.9%, 41.2%, 27.9%, and 28.1% in strength, residual strength, stiffness, and residual stiffness, respectively, compared to the neat epoxy. Furthermore, scanning electron microscopy assessment was utilized to investigate the fracture surfaces of the nanocomposite specimens.

中文翻译：

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多壁碳纳米管/环氧树脂纳米复合材料的蠕变后残余拉伸性能

环氧树脂作为热固性聚合物，由于其粘弹性，即使在室温下也容易受到蠕变载荷的影响。本研究研究了不同官能化多壁碳纳米管（MWCNT）含量的增强环氧树脂对纳米复合材料的蠕变响应和蠕变后残余拉伸性能的影响。在 40°C、200 N 的恒定负载水平下，对含有不同填料含量的纳米复合材料样品和纯环氧树脂样品进行蠕变测试。结果发现，含有 0.3 wt% MWCNT 的纳米复合材料经历了 29.6%、69.1% 和与纯环氧树脂相比，弹性应变、蠕变应变和稳态蠕变应变率分别降低了 74.1%。此外，通过进行拉伸测试，在部分蠕变测试（负载水平为 200 N，持续 150 分钟）之前和之后评估了纯环氧树脂和纳米复合材料样本的拉伸强度和刚度。与纯环氧树脂相比，含有 0.3 wt% MWCNT 的纳米复合材料的强度、残余强度、刚度和残余刚度分别显着提高了 35.9%、41.2%、27.9% 和 28.1%。此外，利用扫描电子显微镜评估来研究纳米复合材料样品的断裂表面。