Mechanical Properties of Cellulose Nanocrystal (CNC) Bundles: Coarse-Grained Molecular Dynamic Simulation

Abstract

Cellulose nanocrystals (CNCs) is a promising biodegradable nanomaterial with outstanding physical, chemical, and mechanical properties for many applications. Although aligned CNCs can self-assemble into bundles, their mechanical performance is reduced by interfacial strength between CNCs and a twisted structure. In this paper, we employ developed coarse-grained (CG) molecular dynamic (MD) simulations to investigate the influence of twist and interface energy on the tensile performance of CNC bundles. CNC bundles of different sizes (number of particles) are tested to also include the effect of size on mechanical performance. The effect of interfacial energy and twist on the mechanical performance shows that elastic modulus, strength, and toughness are more sensitive to twisted angle than interfacial energy. In addition, the effect of size on the bundle and twist on their mechanical performance revealed that both size and twist have a significant effect on the results and can reduce the strength and elastic modulus by 75% as a results of covalent bond dissociation. In addition, a comparison of the broken regions for different values of twist shows that by increasing the twist angle the crack propagates in multiple locations with a twisted shape.

A novel supra coarse-grained model for cellulose

“…We have calculated the axial elastic modulus (E) for the sCG model by pulling one end of the CNC while keeping the other end fixed (Glass et al 2012;Shishehbor et al 2018;Ramezani and Golchinfar 2019). Hereby we obtained the stress-strain curve (Fig.…”

“…Cellulose has been the subject of many molecular simulation studies. Some of these studies focus only at the surface phenomena and modifications of CNC, (Chen et al 2017;Zhou et al 2015;Bergenstråhle et al 2008;Paajanen et al 2016;Chundawat et al 2011) while many others simulate whole CNC, both at atomistic (Chen et al 2017;Zhou et al 2015;Bergenstråhle et al 2008;Paajanen et al 2016;Chundawat et al 2011;Matthews et al 2006;Conley et al 2016;Oehme et al 2015;Djahedi et al 2015;Paajanen et al 2019;Ciesielski et al 2019) and coarsegrained representations (López et al 2009;Wohlert and Berglund 2011;López et al 2015;Mehandzhiyski and Zozoulenko 2019;Glass et al 2012;Fan and Maranas 2015;Markutsya et al 2013;Shishehbor et al 2018;Shishehbor and Zavattieri 2019;Ramezani and Golchinfar 2019;Srinivas et al 2011;Poma et al 2015Poma et al , 2016Poma et al , 2017. All-atom molecular dynamics (AA-MD) studies are able to simulate the crystal structure of cellulose in a perfect agreement with the experimental crystal structure of different cellulose allomorphs and provide a detailed atomistic picture for the structure and dynamics of CNC (Chundawat et al 2011).…”

Changes in Mechanical Properties of Polyhydroxyalkanoate with Double Silanized Cellulose Nanocrystals Using Different Organosiloxanes

“…There are several kinds of nanocellulose, and cellulose nanocrystals (CNCs) are the most common form of cellulose-based nanofiller. CNCs are mainly produced by acid treatments, and the diameter and length of CNCs are 5 to 20 nm and 100 nm to several µm, respectively [21,22]. Its inherent structural properties, such as its significant aspect ratio, and high strength, stiffness, and surface area, make CNC favorable as a nanofiller in composites.…”

Tuning the Mechanical and Adhesion Properties of Carbon Nanotubes Using Aligned Cellulose Wrap (Cellulose Nanotube): A Molecular Dynamics Study

“…In addition to experimental observations, the molecular dynamic (MD) method has been extensively used in the past for mechanical properties of CNT [11,33], CNC [24,29,31,[34][35][36][37], polymer wrapped CNT [38][39][40][41], and CNT-polymer nanocomposite [42][43][44]. For example, Yu et al employed MD simulations to show improvement in the interfacial energy of CNT-polymer due to aromatic polymer chains [43].…”