Qiao Jing, Zhang Quan, Wu Chong, Wu Gaohui, Li Longqiu
School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China.
School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, China.
Polymers (Basel). 2022 Jul 29;14(15):3080. doi: 10.3390/polym14153080.
Composites of polyurea (PU) reinforced with milled glass fiber (MG) were fabricated. The volume fraction and length of the milled glass fiber were varied to study their effects on the morphological and mechanical properties of the MG/PU composites. The morphological attributes were characterized with scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The SEM investigations revealed a uniform distribution and arbitrary orientation of milled glass fiber in the polyurea matrix. Moreover, it seems that the composites with longer fiber exhibit better interfacial bonding. It was found from the FTIR studies that the incorporation of milled glass fiber into polyurea leads to more phase mixing and decreases the hydrogen bonding of the polyurea matrix, while having a negligible effect on the H-bond strength. The compression tests at different strain rates (0.001, 0.01, 0.1, 1, 2000 and 3000 s) and dynamic mechanical properties over the temperature range from -30 to 100 °C at 1 Hz were performed. Experimental results show that the compressive behavior of MG/PU composites is nonlinear and strain-rate-dependent. Both elastic modulus and flow stress at any given strain increased with strain rate. The composites with higher fiber volume fraction and longer fiber length are more sensitive to strain rate. Furthermore, the elastic modulus, stress at 65% strain and energy absorption capability were studied, taking into account both the effect of fiber volume fraction and mean fiber length. It is noted that an increase in fiber volume fraction and fiber length leads to an increase in elastic modulus, stress at 65% strain and absorbed energy up to ~103%, 83.0% and 137.5%, respectively. The storage and loss moduli of the composites also increase with fiber volume fraction and fiber length. It can be concluded that the addition of milled glass fiber into polyurea not only improves the stiffness of the composites but also increases their energy dissipative capability.
制备了用磨碎玻璃纤维（MG）增强的聚脲（PU）复合材料。改变磨碎玻璃纤维的体积分数和长度，以研究它们对MG/PU复合材料的形态和力学性能的影响。用扫描电子显微镜（SEM）和傅里叶变换红外（FTIR）光谱对形态特征进行了表征。SEM研究表明，磨碎玻璃纤维在聚脲基体中分布均匀且取向任意。此外，似乎较长纤维的复合材料表现出更好的界面结合。FTIR研究发现，将磨碎玻璃纤维加入聚脲中会导致更多的相混合，并降低聚脲基体的氢键作用，而对氢键强度的影响可忽略不计。在不同应变率（0.001、0.01、0.1、1、2000和3000 s）下进行了压缩试验，并在1 Hz频率下在-30至100°C的温度范围内进行了动态力学性能测试。实验结果表明，MG/PU复合材料的压缩行为是非线性的且依赖于应变率。在任何给定应变下，弹性模量和流动应力均随应变率的增加而增加。纤维体积分数较高且纤维长度较长的复合材料对应变率更为敏感。此外，考虑到纤维体积分数和平均纤维长度的影响，研究了弹性模量、65%应变时的应力和能量吸收能力。值得注意的是，纤维体积分数和纤维长度的增加分别导致弹性模量、65%应变时的应力和吸收能量增加约103%、83.0%和137.5%。复合材料的储能模量和损耗模量也随纤维体积分数和纤维长度的增加而增加。可以得出结论，向聚脲中添加磨碎玻璃纤维不仅提高了复合材料的刚度，还增加了它们的能量耗散能力。
