Zhang Kai, Sun Yongyang, Wang Fangxin, Liang Wenyan, Wang Zhenqing
College of Aerospace and Civil Engineering, Harbin Engineering University, Harbin 150001, China.
Department of Mechanical Engineering, National University of Singapore, Singapore 117576, Singapore.
Polymers (Basel). 2020 Aug 12;12(8):1809. doi: 10.3390/polym12081809.
As a type of environmentally-friendly and low-cost natural material, bamboo fibers exhibit excellent mechanical properties. In this study, a bamboo fiber reinforced polybenzoxazine composite was fabricated by an improved hot-pressing process. The dynamic compressive behaviors of neat benzoxazine and its composite were comparatively studied by an SHPB (split Hopkinson pressure bar) apparatus. SHPB tests showed that the benzoxazine matrix and its composite exhibited significantly positive strain rate sensitivity at nominal strain rates in the range of 0.006-2500/s. During the impact loadings, the progressive deformation and failure of neat benzoxazine and bamboo composite were investigated by capturing real-time images with a high-speed camera. In comparison with neat benzoxazine, the bamboo composite had slightly higher maximum compressive stress under the same strain rates. It is noteworthy that the crashworthiness of the composite was remarkably better than that of neat benzoxazine due to the incorporation of bamboo fibers. For example, the energy absorption of bamboo composite was 105.7% higher than that of neat benzoxazine at a strain rate of 2500/s. The dynamic compressive properties of benzoxazine resin were much better than most of the conventional thermosetting resins. These results could guide the future application of this kind of composites.
作为一种环保且低成本的天然材料，竹纤维具有优异的力学性能。在本研究中，通过改进的热压工艺制备了竹纤维增强聚苯并恶嗪复合材料。采用分离式霍普金森压杆（SHPB）装置对纯聚苯并恶嗪及其复合材料的动态压缩行为进行了对比研究。SHPB试验表明，聚苯并恶嗪基体及其复合材料在0.006 - 2500/s的名义应变率范围内表现出显著的正应变率敏感性。在冲击加载过程中，通过高速摄像机捕捉实时图像，研究了纯聚苯并恶嗪和竹复合材料的渐进变形与破坏情况。与纯聚苯并恶嗪相比，竹复合材料在相同应变率下具有略高的最大压缩应力。值得注意的是，由于加入了竹纤维，复合材料的抗撞击性能明显优于纯聚苯并恶嗪。例如，在2500/s的应变率下，竹复合材料的能量吸收比纯聚苯并恶嗪高105.7%。聚苯并恶嗪树脂的动态压缩性能比大多数传统热固性树脂要好得多。这些结果可为这类复合材料的未来应用提供指导。
