The application of plant fiber‐reinforced epoxy plastic is severely limited by its relatively low mechanical properties, especially for its brittleness and weak interlaminar properties. The physical and mechanical properties in both nano‐ and macro‐scales of polyurethane/epoxy interpenetration networks were deeply investigated through dynamic mechanical analysis, atomic force microscope and the tensile tests. The atomic force microscope analysis shows that proper amount of polyurethane and evenly distribution could improve the mechanical properties of the resin cast due to the polyurethane/epoxy interpenetrating networks fix the phase zone and increases the strength and stiffness of the system and this was proven with macroscale tensile tests. Moreover, it is impressive to notice that with addition of 15 wt% of polyurethane into epoxy, the initial fracture toughness of its corresponding composite exhibits 48% enhancement. The results in this study indicate that polyurethane/epoxy interpenetration networks show positive effect on improving the interfacial and interlaminar properties of plant fiber reinforced composites.

中文翻译：

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聚氨酯/环氧互穿聚合物及其亚麻纤维增强复合材料的形态和力学行为

植物纤维增强环氧塑料的应用由于其相对较低的机械性能而受到严重限制，尤其是其脆性和较弱的层间性能。通过动态力学分析，原子力显微镜和拉伸试验，深入研究了聚氨酯/环氧互穿网络在纳米和宏观尺度上的物理和力学性能。原子力显微镜分析表明，由于聚氨酯/环氧互穿网络固定了相区并增加了系统的强度和刚度，因此适当数量的聚氨酯和均匀分布可以改善树脂铸件的机械性能，这在宏观上得到了证明。拉伸试验。此外，令人印象深刻的是，在环氧树脂中添加15 wt％的聚氨酯后，其相应复合材料的初始断裂韧性提高了48％。这项研究的结果表明，聚氨酯/环氧树脂互穿网络对改善植物纤维增强复合材料的界面和层间性能显示出积极作用。