Abstract Nanofibrillated fibers (NFC) has been largely used as reinforcing filler to improve the properties of polymer matrix because of their unique properties such as high aspect ratio, good aqueous stability, high specific strength and stiffness. However, the full potential of NFC as reinforcing agent has not been realized because of its poor dispersion and random distribution in polymer matrix. In this work, we demonstrate the importance of alignment of NFC to determine the mechanical properties of polymer via applying alternative current (AC) electric field and using thermoplastic polyurethane (TPU) as the matrix. The TPU/NFC nanocomposites were prepared via solution casting method and the effect of parameters of the applied electric field (amplitude, frequency as well as the duration of application) on the orientation degree of NFC and the final properties of TPU/NFC nanocomposites are systematically investigated. It was found that NFC could be easily oriented under effect of AC due to electric induced polarization. The prepared anisotropic TPU/NFC composites exhibit 2.07 and 1.82 times increase of tensile strength and elongation at break in the parallel direction than that in the vertical direction for the anisotropic samples, respectively. It was also interesting, to find that the samples with aligned NFC exhibit an increased dielectric constant with lower dielectric loss, which could provide an idea to fabricate high performance dielectric materials.

中文翻译：

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热塑性聚氨酯基质中纳米原纤化纤维素的电场诱导排列

摘要 纳米原纤化纤维(NFC)因其高纵横比、良好的水稳定性、高比强度和刚度等独特性能而被广泛用作增强填料以改善聚合物基体的性能。然而，NFC 作为增强剂的全部潜力尚未实现，因为其在聚合物基体中的分散性和随机分布较差。在这项工作中，我们证明了通过施加交流电 (AC) 电场和使用热塑性聚氨酯 (TPU) 作为基质来确定聚合物机械性能的 NFC 对齐的重要性。TPU/NFC 纳米复合材料是通过溶液浇铸法和外加电场参数（振幅、应用的频率和持续时间）对 NFC 取向度和 TPU/NFC 纳米复合材料的最终性能进行了系统研究。发现由于电感应极化，NFC在交流电的作用下可以很容易地定向。制备的各向异性 TPU/NFC 复合材料在平行方向上的拉伸强度和断裂伸长率分别是各向异性样品在垂直方向上的 2.07 倍和 1.82 倍。同样有趣的是，发现具有对齐 NFC 的样品表现出更高的介电常数和更低的介电损耗，这可以提供制造高性能介电材料的想法。发现由于电感应极化，NFC在交流电的作用下可以很容易地定向。制备的各向异性 TPU/NFC 复合材料在平行方向上的拉伸强度和断裂伸长率分别是各向异性样品在垂直方向上的 2.07 倍和 1.82 倍。同样有趣的是，发现具有对齐 NFC 的样品表现出更高的介电常数和更低的介电损耗，这可以提供制造高性能介电材料的想法。发现由于电感应极化，NFC在交流电的作用下可以很容易地定向。制备的各向异性 TPU/NFC 复合材料在平行方向上的拉伸强度和断裂伸长率分别是各向异性样品在垂直方向上的 2.07 倍和 1.82 倍。同样有趣的是，发现具有对齐 NFC 的样品表现出更高的介电常数和更低的介电损耗，这可以提供制造高性能介电材料的想法。