Abstract Structural composites with high fracture toughness have wide applications in various fields. However, achieving high toughening efficiency at low fabricating cost is still challenging. Here, one-dimensional carbon nanofibers (CNFs) were incorporated into the ethylene-octene copolymer (POE)-toughened polypropylene (PP) blends. The fracture behaviors of the samples were systematically researched under different load conditions, such as impact load condition, three-point bending test and single-edge notched tensile (SENT) measurement, and then the toughening mechanisms were proposed. The results indicated that CNFs dramatically enhanced the fracture toughness of the PP/POE blends due to that CNFs prevented the initiation and propagation of crazes. Furthermore, through incorporating an additional annealing treatment, the fracture mechanism of composites changed from crazing fracture to shear yielding-crazing fracture, which endowed CNFs with more apparent toughening effect. For example, at POE and CNF contents of 25 wt% and 1 wt%, the annealed composite sample showed the impact strength of 69.4 kJ/m2 and elongation at break of 395.3%, which were increased by 208.4% and 92.0% compared with the unannealed binary blend, respectively. This work gives a novel insight to understand the toughening effect of one-dimensional nanofillers in the plastics/elastomer blends, and the methods may be used to toughen the other blend composites.

中文翻译：

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通过调整微米级损伤机制制备低弹性体含量的超韧聚丙烯基纳米复合材料

摘要 具有高断裂韧性的结构复合材料在各个领域都有广泛的应用。然而，以低制造成本实现高增韧效率仍然具有挑战性。在这里，一维碳纳米纤维（CNF）被加入到乙烯-辛烯共聚物（POE）-增韧聚丙烯（PP）共混物中。系统研究了样品在不同载荷条件下的断裂行为，如冲击载荷条件、三点弯曲试验和单边缺口拉伸（SENT）测量，然后提出了增韧机制。结果表明，由于 CNF 阻止了裂纹的产生和扩展，CNF 显着提高了 PP/POE 共混物的断裂韧性。此外，通过加入额外的退火处理，复合材料的断裂机制由开裂断裂转变为剪切屈服-开裂断裂，使CNFs具有更明显的增韧作用。例如，在 POE 和 CNF 含量分别为 25 wt% 和 1 wt% 的情况下，退火复合材料样品的冲击强度为 69.4 kJ/m2，断裂伸长率为 395.3%，与之前相比分别提高了 208.4% 和 92.0%。分别为未退火的二元混合物。这项工作为了解一维纳米填料在塑料/弹性体混合物中的增韧效果提供了新的见解，并且该方法可用于增韧其他混合物复合材料。退火复合样品的冲击强度为 69.4 kJ/m2，断裂伸长率为 395.3%，与未退火的二元混合物相比，分别提高了 208.4% 和 92.0%。这项工作为了解一维纳米填料在塑料/弹性体混合物中的增韧效果提供了新的见解，并且该方法可用于增韧其他混合物复合材料。退火复合样品的冲击强度为 69.4 kJ/m2，断裂伸长率为 395.3%，与未退火的二元混合物相比，分别提高了 208.4% 和 92.0%。这项工作为了解一维纳米填料在塑料/弹性体混合物中的增韧效果提供了新的见解，并且该方法可用于增韧其他混合物复合材料。