In this study, carbon-fiber-reinforced epoxy composites were interleaved by poly(phenylene oxide) (PPO) particles to improve their delamination resistance. The morphology of PPO particles at the interlayer was visually observed by a fluorescence microscope. The effects of the PPO particle size and loading level on Mode I and Mode II interlaminar fracture toughness of the interleaved laminates were investigated by standard double cantilever beam (DCB) and end-notched flexure (ENF) tests. The results indicated that the toughening efficiency of PPO was inversely proportional to the particle size. Notably, the laminate interleaved by 10 wt % small-sized PPO particles (10–50 μm) exhibited 65% and 40% enhancements of Mode I and Mode II interlaminar fracture toughness, respectively. The observations of fracture surfaces showed evidence of the toughening mechanisms induced by PPO particles, including plastic deformation of the matrix resin, crack bridging, crack deflection, crack pinning, and resin hackles.

中文翻译：

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聚苯醚颗粒增韧碳纤维增强环氧树脂复合材料的层间断裂韧性

在这项研究中，碳纤维增强的环氧复合材料与聚苯醚（PPO）颗粒交错插入，以提高其抗分层性。通过荧光显微镜目测观察中间层上的PPO颗粒的形态。通过标准双悬臂梁（DCB）和端切口挠曲（ENF）测试，研究了PPO粒度和载荷水平对交错层压板的I型和II型层间断裂韧性的影响。结果表明，PPO的增韧效率与粒径成反比。值得注意的是，由10 wt％的小尺寸PPO颗粒（10-50μm）交错而成的层压板分别显示出模式I和模式II层间断裂韧性分别提高了65％和40％。