The incorporation of rigid nanoparticles has proven to enhance microcracking resistance in carbon fibre reinforced polymer (CFRP) composites at cryogenic temperatures, enabling CFRP tanks to store cryogenic liquid like hydrogen without requiring liners. Herein, we investigate efficacy of low-modulus soft nanoparticles in addressing the microcracking challenges inherent in CFRP at cryogenic temperatures. By incorporating a tri-block copolymer (BCP) into an epoxy, nano-structured fillers with an average diameter of approximately 100 nm are formed. Experimental results reveal that, at a 2.5 wt% loading, the BCP significantly increase the fracture energy of the nanocomposite by 392% at −196 °C while maintaining stiffness and strength. More importantly, composite laminates made with the BCP-modified nanocomposite matrix can withstand cryogenic temperatures without matrix microcracking, even when they contain multiple plies with the same orientation, such as [0/90], which are known to be highly susceptible to matrix microcracking at cryogenic temperatures. An advanced high-fidelity micromechanical model revealed that the observed toughening effect of nanostructured block copolymer at cryogenic temperatures can be attributed to the increased fracture resistance of the nanocomposite matrix. The findings of this research demonstrate that low concentration of block copolymer can effectively mitigate the initiation and propagation of matrix microcracks in carbon fibre composites at ultra-cold temperatures.

中文翻译：

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通过纳米结构嵌段共聚物增韧环氧树脂以减轻碳纤维复合材料在低温下的基体微裂纹

事实证明，加入刚性纳米粒子可以增强碳纤维增强聚合物 (CFRP) 复合材料在低温下的抗微裂性，使 CFRP 储罐能够储存氢气等低温液体，而无需内衬。在此，我们研究了低模量软纳米颗粒在解决低温下 CFRP 固有的微裂纹挑战方面的功效。通过将三嵌段共聚物（BCP）掺入环氧树脂中，形成平均直径约为100 nm的纳米结构填料。实验结果表明，在 2.5 wt% 的负载量下，BCP 在-196 °C 下使纳米复合材料的断裂能显着增加 392%，同时保持刚度和强度。更重要的是，用 BCP 改性的纳米复合材料基体制成的复合材料层压板可以承受低温而不会出现基体微裂纹，即使它们包含具有相同方向的多个层（例如 [0/90]），众所周知，这些层极容易出现基体微裂纹。在低温下。先进的高保真微机械模型表明，在低温下观察到的纳米结构嵌段共聚物的增韧效果可归因于纳米复合材料基体的抗断裂性增加。本研究结果表明，低浓度的嵌段共聚物可以有效减轻超冷温度下碳纤维复合材料中基体微裂纹的萌生和扩展。