What do we still need to understand to commercialize cellulose nanomaterials?^†

Abstract

What are cellulose nanomaterialsand why are they of interest?Cellulose nanomaterials (CNM) are naturally occurring nanoparticles present in lignocellulosic biomass (e.g., trees, grasses, municipal waste), bacteria (e.g., acetobacter) and invertebrate sea creatures (e.g., tunicates). Over the past decade, numerous applications for CNM have been developed and investigated worldwide. 1-10Cellulose nanocrystals (CNC) were first isolated in the laboratory by Mukherjee and Woods in 1953, 11 and a commercially scalable process for cellulose nanofiber (CNF) production was invented by ITT Rayonier in 1977. 12,13 Since then, several inventions and techniques have led to the development of pilot-scale production methods which have been implemented across the globe (CelluForce in Canada, American Process, Inc. in the United States of America and Innventia in Sweden to name a few). CNM are an attractive alternative to other high-aspect-ratio nanoparticles, such as carbon nanotubes and silica nanowhiskers, due to their renewable, sustainable origins and expected low toxicity. (Toxicology studies are ongoing but 'powdered cellulose' has recently been placed on the list of Permitted Food Additives in Canada. )Cellulose consists of glucose molecules linked together into polysaccharide chains, which align to form nanocrystalline domains. The hydroxyl substituent groups on each repeat unit form both inter-and intra-chain hydrogen bonds, leading to unique mechanical and thermal properties. 7,15 The nanocrystalline domains are linked together into nanofiber bundles by flexible, amorphous hemicellulose regions. Various processing techniques have been developed to isolate the two general classes of CNM -that is, cellulose nanofibrils and the individual CNC. Isolation of CNC is What do we still need to understand to commercialize cellulose nanomaterials? Davis, Grolman, Karim and Gilman Published with permission by the ICE under the CC-BY license.

Socially‐Directed Development of Materials for Structural Color

“…Cellulose additionally offers high stiffness, good thermal management, high tensile strength, a high strength‐to‐weight ratio, and optical tunability that can be harnessed in composite systems and transparent films. [ 150 ] Co‐assembly with other polymers and surfactants allows for more durable and multifunctional composites and materials, [ 145 ] making it appealing as a production raw material.…”

“…[ 41 ] Manufacturing variability has been correlated with overdesign and material waste due to cost and energy requirements. [ 177 ] Efforts toward further standardization may be hampered as measurement and characterization methods are costly and time‐consuming, and are thus minimally amenable to large‐scale industrial processing, [ 150 ] though researchers are actively testing scalable characterization methods. [ 173 ] In order for this material to be truly commercially feasible, real‐time, large‐scale monitoring of properties is needed, and batch‐to‐batch consistency must be achievable.…”

Thermoplastic Starch Nanocomposites Reinforced with Cellulose Nanocrystal Suspensions Containing Residual Salt from Neutralization

“…[ 58 ] Overall, a more energy‐ and resource‐efficient production method is required to successfully commercialize CNCs. [ 59 ]…”

“…[58] Overall, a more energy-and resource-efficient production method is required to successfully commercialize CNCs. [59] In this context, Metzger et al designed an economic separation process to produce colloidally stable CNCs from neutralized reactant solutions. [60] After hydrolysis, the reactant solution is neutralized with a base, such as sodium hydroxide, to form a secondary sulfate (Na 2 SO 4 ).…”

Enhanced dispersion and properties of a two-component epoxy nanocomposite using surface modified cellulose nanocrystals

“…Cellulose nanocrystals (CNCs) belongs to a class of emerging cellulose based sustainable nanomaterials derived from biomass. [1][2][3][4] CNCs are whisker-shaped cellulose nanoparticles with high aspect ratio (3-10nm wide and 50 to 500nm long). [2] They are typically produced via acid hydrolysis of cellulose-rich source materials such as wood pulp.…”