Chemically Cross-Linked Cellulose Nanocrystal Aerogels with Shape Recovery and Superabsorbent Properties

Abstract

Cellulose nanocrystals (CNCs) are entering the marketplace as new high-strength nanoadditives from renewable resources. These high aspect ratio particles have potential applications as rheological modifiers, reinforcing agents in composites, coatings, and porous materials. In this work, chemically cross-linked CNC aerogels were prepared based on hydrazone cross-linking of hydrazide and aldehyde-functionalized CNCs. The resulting aerogels were ultralightweight (5.6 mg/cm3) and highly porous (99.6%) with a bimodal pore distribution (mesopores <50 nm and macropores >1 μm). Chemically cross-linked CNC aerogels showed enhanced mechanical properties and shape recovery ability, particularly in water, compared to previous reports of physically cross-linked CNC aerogels. Specifically, the aerogel shape recovered more than 85% after 80% compression, even after 20 compress and release cycles. These CNC aerogels can absorb significant amounts of both water (160 ± 10 g/g of aerogel) and dodecane (72 ± 5 g/g of aerogel) with cyclic absorption capacity. We demonstrate that CNC aerogels can be used as superabsorbents and for oil/water separations and they may also find application as insulating or shock-absorbing materials. The cross-linking technology developed here presents new ways to design CNC networked structures and suggests an alternate route to incorporate CNCs into matrix materials, such as epoxies and foams.

3D bioprinting of liver-mimetic construct with alginate/cellulose nanocrystal hybrid bioink

“…renewability, low density, high mechanical strength, large and highly reactive surfaces, and low cytotoxicity) have attracted a significant amount of research interests for a variety of applications, including tissue engineering. [25][26][27][28][29] CNC can be mixed into various polymer matrices to reinforce the mechanical strength and induce shear thinning behavior. 28,30,31 For example, Siqueira et al developed a hybrid ink comprising of CNC, 2-hydroxyethyl methacrylate (HEMA) monomer and polyether urethane acrylate (PUA).…”

Applications of cellulose nanomaterials in pharmaceutical science and pharmacology

“…Due to the much smaller lengths and high rigidity, crosslinking is not so commonly used for CNCs as CNFs. A typical example was to use hydrazide and aldehyde surface functionalization, leading to ultralightweight (5.6 mg/cm 3 ) and highly porous (99.6%) aerogels [70].…”

Spherical and rod-like dialdehyde cellulose nanocrystals by sodium periodate oxidation: Optimization with double response surface model and templates for silver nanoparticles

“…As the nanofillers, the requirement of CNs surface group varies with the different applications. The traditional methods like acid hydrolysis [4,7], enzyme-assisted hydrolysis [8] and mechanical treatments [9] can extract the CNs with hydroxyl groups, which are usually modified into other functional groups for further applications. Recently, CNs with functional groups (carboxyl or aldehyde groups) have been developed by 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO) [10,11], ammonium persulfate (APS) [12], two-step approach combined acid hydrolysis and NaIO 4 oxidations [13][14][15], and one-step NaIO 4 oxidation [16].…”

“…cellulose nanocrystal (DACN) by two-step approach NaIO 4 oxidation, in which DACN with 50-376 nm in length and 3-18 nm in diameter were prepared by the sulfuric acid hydrolysis of fibers (cotton fibers and bleached softwood pulp) and then NaIO 4 oxidation [13][14][15]. However, the two-step approach NaIO 4 oxidation was complicated and needed environmental unfriendly acid hydrolysis process that leads to the low yield of DACN.…”

“…However, the two-step approach NaIO 4 oxidation was complicated and needed environmental unfriendly acid hydrolysis process that leads to the low yield of DACN. More recently, one-step NaIO 4 oxidation was used to fabricate DACN efficiently [16].…”