Indian Institute of Science, Bangalore 560012, India.
Department of Materials Engineering, KU Leuven, Leuven 3000, Belgium.
Biomacromolecules. 2022 Jun 13;23(6):2243-2254. doi: 10.1021/acs.biomac.1c01110. Epub 2022 May 12.
Cellulose nanocrystals (CNCs) offer excellent mechanical properties. However, measuring the strength by performing reliable experiments at the nanoscale is challenging. In this paper, we model Iβ crystalline cellulose using reactive molecular dynamics simulations. Taking the fibril twist into account, structural changes and hydrogen-bonding characteristics of CNCs during the tensile test are inspected and the failure mechanism of CNCs is analyzed down to the scale of individual bonds. The C4-O4 glycosidic bond is found to be responsible for the failure of CNCs. Finally, the effect of strain rate on ultimate properties is analyzed and a nonlinear model is used to predict the ultimate strength of 9.2 GPa and ultimate strain of 8.5% at a 1 s strain rate. This study sheds light on the applications of cellulose in nanocomposites and further modeling of cellulose nanofibres.
纤维素纳米晶体（CNCs）具有优异的机械性能。然而，在纳米尺度上进行可靠的实验来测量其强度具有挑战性。在本文中，我们使用反应分子动力学模拟对 Iβ 晶纤维素进行建模。考虑到原纤扭转，检查了在拉伸试验过程中 CNCs 的结构变化和氢键特性，并分析了直至单个键的尺度的 CNCs 的失效机制。发现 C4-O4 糖苷键是导致 CNCs 失效的原因。最后，分析了应变速率对极限性能的影响，并使用非线性模型预测在 1 s 应变速率下的极限强度为 9.2 GPa 和极限应变为 8.5%。本研究为纤维素在纳米复合材料中的应用以及纤维素纳米纤维的进一步建模提供了思路。
