Pilot-Scale Production of Cellulosic Nanowhiskers With Similar Morphology to Cellulose Nanocrystals

Abstract

This study describes a class of cellulosic nanomaterials, cellulosic nanowhiskers (CNWs), and demonstrates scaled-up production with acid recovery using less expensive equipment made of common stainless steel rather than glass-lined steel. CNWs produced using concentrated maleic acid (MA) hydrolysis followed by mechanical fibrillation have morphology similar to MA-produced cellulose nanocrystals (CNCs) and sulfuric-acid-produced CNCs (S-CNCs) but differ in crystallinity. Applications of CNWs as a substitute for CNCs for which morphology and surface charge, rather than crystallinity, are the pertinent characteristics are presented. The tested CNW suspensions have a wider viscosity range of 0.001 to 1000 Pa.s over a variety of shear rates of 0.01 to 1000 1/s compared to S-CNCs of 0.001 to 0.1 Pa.s and are better suited for applications such as rheology modification and 3D printing. This study proposes CNWs as a less expensive and sustainable replacement for CNCs in applications that do not require crystalline properties.

Towards sustainable production and utilization of plant-biomass-based nanomaterials: a review and analysis of recent developments

“…The morphologies of MA CNCs (M-CNCs) and M-CNFs were found to correlate well with hydrolysis severity CHF G , i.e., a higher severity results in shorter and thinner M-CNCs and less entangled M-CNFs or even individually separated M-CNFs [ 146 , 148 ]. This observation is clearly supported by Fig.…”

“…The nano-whisker sample shown in Fig. 4 h actually has a lower crystallinity than the corresponding CNCs because it was obtained after mechanical fibrillation [ 126 , 148 ]. Therefore, this type of individually separated nano-whiskers with morphology similar to CNCs may not be called CNCs.…”

“…Scale-up of this production process, from 5 g [ 146 ] (Fig. 4 ) to 750 g [ 148 ] (Fig. 5 ), using CHF G as a scaling factor showed excellent scalability.…”

“…Bottom row: morphologies of CNC from concentrated acid hydrolysis (left: sulfuric acid hydrolysis of spruce dissolving pulp from FPL pilot plant, right: MA hydrolysis of BEP under M2). Reproduced from Wang et al [ 148 ] …”

Refractive Index Change of Cellulose Nanocrystal-Based Electroactive Polyurethane by an Electric Field

“…Cellulose is a well known and abundant biopolymer globally, which consists of a crystal region and amorphous region. The crystal region, so-called cellulose nanocrystal (CNC), has remarkable advantages such as high mechanical specific strength, biocompatibility, nanoscale dimension, and sustainability (Habibi et al, 2010 ; Moon et al, 2011 ; Kim et al, 2015 ; Vanderfleet and Cranston, 2020 ; Wang et al, 2020 ). Typically CNC has lengths of 100–200 nm and cross-sections of 5–20 nm.…”