Abstract Flexural properties of carbon fibre reinforced plastics (CFRPs) with multi-layer interfacial reinforcement of hierarchically structured aramid pulp (AP) fibres were measured at −40 and −100 °C under three-point bending (3 PB) together with unreinforced CFRPs. After curing, the ‘interleaf’ thicknesses were 3.3, 5.6 and 12.2 μm for three different AP areal densities of 0.8, 1.6 and 3.2 g/m2, respectively. 3 PB tests of control and AP reinforced CFRPs were also performed at 20 °C to compare the AP strengthening effects and their variations from ambient temperature to −100 °C. The flexural strength increased up to 30.6% at −100 °C for specimens with 1.6 g/m2 AP in comparison to 24.5% enhancement at room temperature. This finding proves that a proper composite design, i.e. adding tough and flexible short fibres into the brittle-fibre and brittle-matrix system, can indeed enhance the structural performance of CFRPs. The small-scale in-house ‘pre-preg’ fabrication adopted in this study shows that the ultra-thin layers of AP fibres can be potentially incorporated into a large-scale pre-preg production so that the extra step of inserting the interleaving layers can be removed from the composite forming process. In other words, end users can use the AP toughened pre-pregs just like any carbon fibre pre-pregs currently in use without the trouble of interleaving.

中文翻译：

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芳纶浆粕对碳纤维增强塑料低温弯曲性能的影响

摘要 在三点弯曲 (3 PB) 条件下，在 -40 和 -100 °C 下测量了具有分层结构芳纶纸浆 (AP) 纤维多层界面增强的碳纤维增强塑料 (CFRP) 与未增强 CFRP 的弯曲性能。固化后，对于三种不同的 AP 面密度 0.8、1.6 和 3.2 g/m2，“中间”厚度分别为 3.3、5.6 和 12.2 μm。3 控制和 AP 增强 CFRP 的 PB 测试也在 20 °C 下进行，以比较 AP 增强效果及其从环境温度到 -100 °C 的变化。与室温下 24.5% 的增强相比，具有 1.6 g/m2 AP 的试样在 -100 °C 下的弯曲强度增加了 30.6%。这一发现证明了适当的复合设计，即 在脆性纤维和脆性基体体系中加入坚韧而柔韧的短纤维，确实可以增强CFRPs的结构性能。本研究中采用的小规模内部“预浸”制造表明，AP 纤维的超薄层有可能被纳入大规模的预浸生产中，因此插入交错层的额外步骤可以从复合成型过程中去除。换句话说，最终用户可以像目前使用的任何碳纤维预浸料一样使用 AP 增韧预浸料，而无需交织。本研究中采用的小规模内部“预浸”制造表明，AP 纤维的超薄层有可能被纳入大规模的预浸生产中，因此插入交错层的额外步骤可以从复合成型过程中去除。换句话说，最终用户可以像目前使用的任何碳纤维预浸料一样使用 AP 增韧预浸料，而无需交织。本研究中采用的小规模内部“预浸”制造表明，AP 纤维的超薄层有可能被纳入大规模的预浸生产中，因此插入交错层的额外步骤可以从复合成型过程中去除。换句话说，最终用户可以像目前使用的任何碳纤维预浸料一样使用 AP 增韧预浸料，而无需交织。