Abstract Interleaving laminated composites with electrospun nanofibrous mats comes out as a promising micro--scale strategy to strengthen interlaminar regions of laminated composites. The aim of this study is to evaluate the synergetic contribution of nano- and micro-scale mechanisms on interlaminar delamination. For this, carbon nanotubes (CNTs) reinforced polyacrylonitrile (PAN) electrospun hybrid mats were successfully fabricated and utilized as interleaves within the interlaminar region of carbon/epoxy laminated composites. The Mode I interlaminar fracture toughness values were enhanced up to 77% by introducing CNTPAN nanofibrous interleaves. Specifically, the nano-scale toughening mechanisms such as CNTs bridging, CNTs pull-out, and sword-sheath increased the Mode I fracture toughness by 45% with respect to neat PAN nanofibrous interleaves. The related micro- and nano-scale toughening mechanisms were evaluated based on the fracture surface analysis. Atomic force microscopy was also utilized to quantify the magnitude of surface roughness changes on the interlaminar region with respect to multi-scale interleaving reinforcement and correlate surface roughness changes due to crack deflection to increased fracture toughness.

中文翻译：

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具有改进的 I 型层间断裂韧性的 CNT-PAN 混合纳米纤维垫交错碳/环氧树脂层压板

摘要 用电纺纳米纤维垫交错层压复合材料是一种有前景的微尺度策略，可增强层压复合材料的层间区域。本研究的目的是评估纳米和微米尺度机制对层间分层的协同作用。为此，成功制造了碳纳米管 (CNT) 增强的聚丙烯腈 (PAN) 电纺混合垫，并将其用作碳/环氧树脂层压复合材料的层间区域内的交错层。通过引入 CNTPAN 纳米纤维交错层，I 型层间断裂韧性值提高了 77%。具体而言，纳米级增韧机制，如碳纳米管桥接、碳纳米管拉出和剑鞘，使 I 型断裂韧性相对于纯 PAN 纳米纤维交错增加了 45%。基于断口分析评估了相关的微米和纳米级增韧机制。原子力显微镜也被用来量化层间区域表面粗糙度变化的幅度，与多尺度交错增强相关，并将由于裂纹偏转引起的表面粗糙度变化与增加的断裂韧性相关联。