Cellulose nanocrystals and related nanocomposites: Review of some properties and challenges

Abstract

Cellulosic nanoparticles with high Young's modulus, crystallinity, specific surface area, and aspect ratio can be found in the natural structure of plant fibers. Indeed, lignocellulosic fibers consist of semicrystalline cellulose nanofibrils embedded in an amorphous matrix mainly composed of lignin and hemicelluloses. These nanostructures give the mechanical strength to higher plant cells, and are biodegradable, renewable, resistant, and widely available to produce nanocomposites with low density, and improved and controlled mechanical, optical, and barrier properties. Nanoparticles can be extracted from cellulose using a top-down mechanically or chemically assisted deconstructing strategy, and owing to their highly reactive surface ensuing nanomaterials can be chemically modified to tailor their properties for a wide range of applications. This review is limited to cellulose chemically extracted nanocrystals and aims to provide an overview about several aspects that involve this material, including sources, properties, challenges, and perspectives.

Nanocellulose in Thin Films, Coatings, and Plies for Packaging Applications: A Review

“…If one processes plant-based material to remove the lignin and then treats the isolated cellulose with a strong acid or other suitable reagents to degrade and remove the less crystalline domains and any residual hemicelluloses, then, by optimizing the conditions of treatment, one can obtain a suspension of cellulose crystallites (Mariano et al 2014;Nelson et al 2016). Typical sizes of cellulose crystallites range from about 3 to 30 nm in thickness and few hundreds of nm in length, depending on the plant source (Elazzouzi-Hafraoui et al 2008; Eichhorn 2011).…”

An overview on properties and applications of poly(butylene adipate‐co‐terephthalate)–PBAT based composites

“…As a consequence, the development of a PBAT market will only be possible when production costs decrease and when their properties are improved [19]. The addition of low-cost materials (natural fibers and cellulose derivatives) as natural reinforcing agents is an effective way to improve the polymer properties and decrease their final price, while maintaining the biodegradability of the matrix [33][34][35][36][37][38]. However, many challenges remain in this field as well as opportunities waiting to be overcome and incorporated in order to improve the composite performance and allow its industrial-scale preparation [39].…”

Cellulose Nanocrystals as Advanced "Green" Materials for Biological and Biomedical Engineering

“…Cellulose I has a Young's modulus of approximately 137 GPa (with intramolecular hydrogen bonding) and 92 GPa (without intramolecular hydrogen bonding), while cellulose II has a Young's modulus of 113 GPa (Mariano et al, 2014). Compared with glass fibers, which has a Young's modulus of 70 Gpa and a density of 2.6 g cm -3 , crystalline cellulose displays a higher Young's modulus considering that the density for crystalline cellulose is approximately 1.5-1.6 g cm -3 (Mariano et al, 2014). The properties of crystalline cellulose are comparable to those of Kevlar, which has a Young's modulus of 60-125 GPA with a density of approximately 1.45 g cm -3 and to those of steel (200-220 GPa, density around 8 g cm -3 ) (Mariano et al, 2014).…”

“…Compared with glass fibers, which has a Young's modulus of 70 Gpa and a density of 2.6 g cm -3 , crystalline cellulose displays a higher Young's modulus considering that the density for crystalline cellulose is approximately 1.5-1.6 g cm -3 (Mariano et al, 2014). The properties of crystalline cellulose are comparable to those of Kevlar, which has a Young's modulus of 60-125 GPA with a density of approximately 1.45 g cm -3 and to those of steel (200-220 GPa, density around 8 g cm -3 ) (Mariano et al, 2014). The specific Young's modulus of cellulose crystals has found to be greater than the steel.…”