Nanocomposite materials made from cellulose show a great potential as future high-performance and sustainable materials. We show how high aspect ratio cellulose nanofibrils can be efficiently aligned in extrusion to fibers, leading to increased modulus of toughness (area under the stress-strain curve), Young's modulus, and yield strength by increasing the extrusion capillary length, decreasing its diameter, and increasing the flow rate. The materials showed significant property combinations, manifesting as high modulus of toughness (~28-31 MJ/m³) vs. high stiffness (~19-20 GPa), and vs. high yield strength (~130-150 MPa). Wide angle X-ray scattering confirmed that the enhanced mechanical properties directly correlated with increased alignment. The achieved moduli of toughness are approximately double or more when compared to values reported in the literature for corresponding strength and stiffness. Our results highlight a possibly general pathway that can be integrated to gel-spinning process, suggesting the hypothesis that that high stiffness, strength and toughness can be achieved simultaneously, if the alignment is induced while the CNF are in the free-flowing state during the extrusion step by shear at relatively low concentration and in pure water, after which they can be coagulated.

中文翻译：

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使纤维素纳米原纤维分散体排列成更坚韧的纤维。

由纤维素制成的纳米复合材料具有巨大的潜力，可作为未来的高性能和可持续性材料。我们展示了如何通过增加挤出毛细管的长度，减小其直径，将高纵横比的纤维素纳米原纤维在挤出过程中有效地排列成纤维，从而提高韧性模量（应力-应变曲线下的面积），杨氏模量和屈服强度，并增加流量。这些材料表现出显着的性能组合，表现为高韧性模量（〜28-31 MJ / m ³）与高刚度（〜19-20 GPa），以及高屈服强度（〜130-150 MPa）。广角X射线散射证实增强的机械性能与增加的对准直接相关。当与相应强度和刚度的文献报道的值相比时，所获得的韧性模量约为两倍或更多。我们的结果强调了可能与凝胶纺丝过程整合的一般途径，这表明假说，如果在CNF处于自由流动状态时诱导排列，则可以同时实现高刚度，强度和韧性。通过在相对较低的浓度和纯水中通过剪切进行挤出步骤，然后将它们凝结。