碳纳米管膜层间改性碳纤维/双马来酰亚胺复合材料的结构调控及性能

对比研究了热塑性层间增韧和碳纳米管(CNT)膜层间混杂碳纤维(CF)/双马来酰亚胺复合材料不同层间结构调控方法，分析了其复合材料的压缩、动态力学、导电和电磁屏蔽等性能的变化。结果表明，热密实可显著降低层间CNT膜的厚度，抑制其局部富树脂程度，CNT膜-CF混杂复合材料的压缩强度得以提升，其压缩断口形貌明显不同于初始的CF复合材料。对比而言，热塑性树脂层间增韧CF复合材料的压缩强度明显低于CNT膜/CF混杂复合材料。CNT膜的加入贯通了混杂复合材料的层间导电通路，其厚度方向电导率提高了3个数量级，然而不同复合材料的体积电导率则表现出明显的“木桶效应”。值得关注的是，CNT膜层间混杂对提高CF复合材料的电磁屏蔽特性作用显著，其中致密CNT膜混杂复合材料的电磁屏蔽效能可达到90 dB。 

Structure adjustment and properties of carbon nanotube film interlaminar modified carbon fiber/bismaleimide composites

The interlayer structure adjusting methods were studied on carbon fiber (CF)/bismaleimide composite materials, conducted respectively by thermoplastic interlaminar toughening and carbon nanotube (CNT) film hybridizing in contrast. The changes of compression properties, dynamic mechanical properties, electrical conductivities and electromagnetic shielding properties of the modified CF composites were analyzed. The results show that thermal compaction processing reduces the thickness of the CNT film significantly, suppressing the local resin-rich of the interlayer CNT region. The compressive strengths of the CNT film-CF hybrid composites are improved, with the fracture morphologies obviously different from that of the CF composites. In comparison, the thermoplastic interlaminar toughened CF composites show much lower compression strengths than the CNT film/CF hybrid composites. Additionally, the interlaminar electrical conductive paths are penetrated by the CNT networks of the hybrid composites, hence the thickness direction conductivities are increased by 3 orders of magnitude. However, the volumetric electrical conductivities of the diverse hybrid composites exhibit an evident “Cannikin Law”. It is noteworthy that the CNT film interlaminar hybrid can dramatically improve the electromagnetic shielding properties of the CF composite, reaching up to 90 dB for the dense CNT film hybrid composite.