Cellulose Nanocrystals: Tensile Strength and Failure Mechanisms Revealed Using Reactive Molecular Dynamics

A Gupta and A Khodayari and ACT van Duin and U Hirn and AW Van Vuure and D Seveno, BIOMACROMOLECULES, 23, 2243-2254 (2022).

DOI: 10.1021/acs.biomac.1c01110

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 1 beta 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 s(-1) strain rate. This study sheds light on the applications of cellulose in nanocomposites and further modeling of cellulose nanofibres.

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