Superior mechanical performance of highly porous, anisotropic nanocellulose–montmorillonite aerogels prepared by freeze casting

Donius, Amalie E.; Liu, Andong; Berglund, Lars A.; Wegst, Ulrike G. K.

doi:10.1016/j.jmbbm.2014.05.012

Cited by 144 publications

(108 citation statements)

References 36 publications

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“…The porosities of the fabricated nanopapers can be increased by replacing the water medium with solvents that are less polar (Sehaqui et al 2011). Light-weight aerogels (Korhonen et al 2011) with highly porous structures can be fabricated by freeze-drying, and the most convoluted drying methods of nanocelluloses under specific conditions enables the fabrication of highly organized and orientated aerogels (Donius et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Mechanical fabrication of high-strength and redispersible wood nanofibers from unbleached groundwood pulp

et al. 2017

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In the past, the direct production of lignincontaining nanofibers from wood materials has been very limited, and nanoscale fibers (nanocelluloses) have been mainly isolated from chemically delignified, bleached cellulose pulp. In this study, we have introduced a newly adapted, heat-intensified disc nanogrinding process for the enhanced nanofibrillation of wood nanofibers (WNF) with a high lignin content (27.4 wt%). The WNF produced this way have many unique and intriguing properties in their naturally occurring form, for example, being able to be dispersed in ethanol and having ethanol solution viscosities higher than water solution viscosities. When WNF nanopapers were formed with ethanol, the properties of the nanofibers were recoverable without a notable decrease in the viscosity or mechanical strength after redispersing them in water. The preservation of lignin in the WNF was noticed as an increase in the water contact angles (89°), the rapid removal of water in the fabrication of the nanopapers, and the enhanced strength of the nanopapers when subjected to high pressure and heat. The nanopapers fabricated from the WNF were mechanically stable, having an elastic modulus of 6.2 GPa, a maximum stress of 103.4 MPa, and a maximum strain of 3.5%. Throughout the study, characteristics of the WNF were compared to those of the delignified and bleached reference cellulose nanofibers. We envision that the exciting characteristics of the WNF and their lower cost of production compared to that of bleached cellulose nanofibers may offer new opportunities for nanocellulose and biocomposite research.

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Section: Introductionmentioning

confidence: 99%

Mechanical fabrication of high-strength and redispersible wood nanofibers from unbleached groundwood pulp

et al. 2017

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“…Nanocellulose materials can be prepared by solvent-free methods, preserving the native cellulose fibril structure, involving only water-based processing. CNF has been used to produce a variety of nanomaterials 1 including aerogels, 2 hydrogels, 3 foams, 4 honeycombs, 5 neat CNF films, 6 porous CNF membranes, CNF/polymer films, 7, 8 CNF/polymer composites for compression molding, injection molding 9-11 etc and a large variety of CNF/inorganic hybrid nanomaterials. [12][13][14] It has been recently reported that CNF/polysaccharide films with improved hygromechanical properties 3 and moisture stability were successfully prepared based on the core-shell nanofiber concept.…”

Section: Introductionmentioning

confidence: 99%

Holocellulose Nanofibers of High Molar Mass and Small Diameter for High-Strength Nanopaper

et al. 2015

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Wood cellulose nanofibers (CNFs) based on bleached pulp are different from the cellulose microfibrils in the plant cell wall in terms of larger diameter, lower cellulose molar mass, and modified cellulose topochemistry. Also, CNF isolation often requires high-energy mechanical disintegration. Here, a new type of CNFs is reported based on a mild peracetic acid delignification process for spruce and aspen fibers, followed by low-energy mechanical disintegration. Resulting CNFs are characterized with respect to geometry (AFM, TEM), molar mass (SEC), and polysaccharide composition. Cellulose nanopaper films are prepared by filtration and characterized by UV-vis spectrometry for optical transparency and uniaxial tensile tests. These CNFs are unique in terms of high molar mass and cellulose-hemicellulose core-shell structure. Furthermore, the corresponding nanopaper structures exhibit exceptionally high optical transparency and the highest mechanical properties reported for comparable CNF nanopaper structures.

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“…In the second stage, a rapid mass loss occurred above 250 o C. It involves oxidative decomposition of the cellulosic molecular chains. A further increase in temperature leads to a slow thermal degradation, followed by a carbonization process in the final stage 24 . With the addition of APP or clay, the corresponding TGA curves changed, showing a new degradation step around 400 o C. This step may be due to the formation of char which delays the decomposition rate.…”

Section: Thermal Stabilitymentioning

confidence: 99%

Green bio-based aerogels prepared from recycled cellulose fiber suspensions

Wang

Sánchez‐Soto

2015

RSC Adv.

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Recycled cellulose fibers (RCF) from waste paper were utilized to prepare bio-based aerogels through an environmentally friendly freeze-drying method. Food thickening agent sodium carboxymethyl cellulose (CMC) served as matrix in the bio-aerogels. The microstructures and mechanical properties of the aerogels have been studied as a function of RCF/CMC content. Sodium montmorrilonite (Na + -MMT) and ammonium polyphosphate (APP) were added to enhance the thermal stability and flame retardancy, which were investigated by thermogravimetric analysis (TGA) and cone calorimeter respectively. It was found that the Na + -MMT significantly improved the fire retardancy of the aerogels and APP played a synergistic effect with it. The initial decomposition temperature increased by 15 o C and the peak of heat release rate decreased from 90 to 49.5 kw/m 2 in the presence of 33% clay. Addition of APP further increased the residue amount and reduced the fire growth rate. Fourier transform infrared spectroscopy (FTIR) was used to analyse the char formed after cone calorimeter tests.

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Superior mechanical performance of highly porous, anisotropic nanocellulose–montmorillonite aerogels prepared by freeze casting

Cited by 144 publications

References 36 publications

Mechanical fabrication of high-strength and redispersible wood nanofibers from unbleached groundwood pulp

Mechanical fabrication of high-strength and redispersible wood nanofibers from unbleached groundwood pulp

Holocellulose Nanofibers of High Molar Mass and Small Diameter for High-Strength Nanopaper

Green bio-based aerogels prepared from recycled cellulose fiber suspensions

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