Micro-mechanics of electrostatically stabilized suspensions of cellulose nanofibrils under steady state shear flow

Soft Matter ◽  
2016 ◽  
Vol 12 (6) ◽  
pp. 1721-1735 ◽  
Author(s):  
F. Martoïa ◽  
P. J. J. Dumont ◽  
L. Orgéas ◽  
M. N. Belgacem ◽  
J.-L. Putaux
Keyword(s):  
Steady State ◽  
Shear Flow ◽  
Cellulose Nanofibrils ◽  
Oxidized Cellulose ◽  
Cellulose Nanofibril ◽  
Aqueous Suspensions

In this study, we characterized and modeled the rheology of TEMPO-oxidized cellulose nanofibril (NFC) aqueous suspensions with electrostatically stabilized and unflocculated nanofibrous structures.

scholarly journals Rapid Water Softening with TEMPO-Oxidized/Phosphorylated Nanopapers

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 136 ◽  
Author(s):  
Andreas Mautner ◽  
Thawanrat Kobkeatthawin ◽  
Florian Mayer ◽  
Christof Plessl ◽  
Selestina Gorgieva ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Cellulose Nanofibrils ◽  
Water Hardness ◽  
Organic Liquids ◽  
Oxidized Cellulose ◽  
Water Softening ◽  
Aqueous Suspensions ◽  
Overall Performance ◽  
Exchange Resins ◽  
Very High

Water hardness not only constitutes a significant hazard for the functionality of water infrastructure but is also associated with health concerns. Commonly, water hardness is tackled with synthetic ion-exchange resins or membranes that have the drawbacks of requiring the awkward disposal of saturated materials and being based on fossil resources. In this work, we present a renewable nanopaper for the purpose of water softening prepared from phosphorylated TEMPO-oxidized cellulose nanofibrils (PT-CNF). Nanopapers were prepared from CNF suspensions in water (PT-CNF nanopapers) or low surface tension organic liquids (ethanol), named EPT-CNF nanopapers, respectively. Nanopaper preparation from ethanol resulted in a significantly increased porosity of the nanopapers enabling much higher permeances: more than 10,000× higher as compared to nanopapers from aqueous suspensions. The adsorption capacity for Ca2+ of nanopapers from aqueous suspensions was 17 mg g−1 and 5 mg g−1 for Mg2+; however, EPT-CNF nanopapers adsorbed more than 90 mg g−1 Ca2+ and almost 70 mg g−1 Mg2+. The higher adsorption capacity was a result of the increased accessibility of functional groups in the bulk of the nanopapers caused by the higher porosity of nanopapers prepared from ethanol. The combination of very high permeance and adsorption capacity constitutes a high overall performance of these nanopapers in water softening applications.

scholarly journals Alcohol induced gelation of TEMPO-oxidized cellulose nanofibril dispersions

Soft Matter ◽  
2018 ◽  
Vol 14 (45) ◽  
pp. 9243-9249 ◽  
Author(s):  
Marcelo A. da Silva ◽  
Vincenzo Calabrese ◽  
Julien Schmitt ◽  
Duygu Celebi ◽  
Janet L. Scott ◽  
...  
Keyword(s):  
Self Assembly ◽  
Cellulose Nanofibrils ◽  
Oxidized Cellulose ◽  
Cellulose Nanofibril ◽  
Alcoholic Mixtures

Alcohol-induced gelation of partially oxidised cellulose nanofibrils (OCNFs): nanoscale (SAXS) and macroscale (rheology) insights into OCNF self-assembly in aqueous-alcoholic mixtures.

The sol–gel transition of ultra-low solid content TEMPO-cellulose nanofibril/mixed-linkage β-glucan bionanocomposite gels

Soft Matter ◽  
2018 ◽  
Vol 14 (46) ◽  
pp. 9393-9401 ◽  
Author(s):  
Suvi Arola ◽  
Mahmoud Ansari ◽  
Antti Oksanen ◽  
Elias Retulainen ◽  
Savvas G. Hatzikiriakos ◽  
...  
Keyword(s):  
Plant Cell Wall ◽  
Sol Gel ◽  
Cellulose Nanofibrils ◽  
Solid Content ◽  
Cross Linking ◽  
Cell Wall Polysaccharide ◽  
Oxidized Cellulose ◽  
Cellulose Nanofibril ◽  
Sol Gel Transition ◽  
Gel Transition

Ultra-low solid content gels were prepared by physically cross-linking TEMPO-oxidized cellulose nanofibrils (TEMPO-CNF) with the plant-cell-wall polysaccharide, mixed-linkage β-glucan (MLG).

scholarly journals High wet-strength, thermally stable and transparent TEMPO-oxidized cellulose nanofibril film via cross-linking with poly-amide epichlorohydrin resin

RSC Advances ◽  
2017 ◽  
Vol 7 (50) ◽  
pp. 31567-31573 ◽  
Author(s):  
Weisheng Yang ◽  
Huiyang Bian ◽  
Liang Jiao ◽  
Weibing Wu ◽  
Yulin Deng ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Water Resistance ◽  
Cellulose Nanofibrils ◽  
Cross Linking ◽  
Oxidized Cellulose ◽  
Thermally Stable ◽  
Cellulose Nanofibril ◽  
Wet Strength

TEMPO-oxidized cellulose nanofibrils (TOCNs) films cross-linked with different dosages of polyamide epichlorohydrin resin (PAE) show a great water-resistance and thermal stability.

Numerical study of electric field effects on the deformation of two-dimensional liquid drops in simple shear flow at arbitrary Reynolds number

2009 ◽  
Vol 626 ◽  
pp. 367-393 ◽  
Author(s):  
STEFAN MÄHLMANN ◽  
DEMETRIOS T. PAPAGEORGIOU
Keyword(s):  
Steady State ◽  
Shear Flow ◽  
Electric Field ◽  
Electric Fields ◽  
Simple Shear ◽  
Simple Shear Flow ◽  
Physical Parameters ◽  
Shear Stresses ◽  
Two Dimensional ◽  
Liquid Drops

The effect of an electric field on a periodic array of two-dimensional liquid drops suspended in simple shear flow is studied numerically. The shear is produced by moving the parallel walls of the channel containing the fluids at equal speeds but in opposite directions and an electric field is generated by imposing a constant voltage difference across the channel walls. The level set method is adapted to electrohydrodynamics problems that include a background flow in order to compute the effects of permittivity and conductivity differences between the two phases on the dynamics and drop configurations. The electric field introduces additional interfacial stresses at the drop interface and we perform extensive computations to assess the combined effects of electric fields, surface tension and inertia. Our computations for perfect dielectric systems indicate that the electric field increases the drop deformation to generate elongated drops at steady state, and at the same time alters the drop orientation by increasing alignment with the vertical, which is the direction of the underlying electric field. These phenomena are observed for a range of values of Reynolds and capillary numbers. Computations using the leaky dielectric model also indicate that for certain combinations of electric properties the drop can undergo enhanced alignment with the vertical or the horizontal, as compared to perfect dielectric systems. For cases of enhanced elongation and alignment with the vertical, the flow positions the droplets closer to the channel walls where they cause larger wall shear stresses. We also establish that a sufficiently strong electric field can be used to destabilize the flow in the sense that steady-state droplets that can exist in its absence for a set of physical parameters, become increasingly and indefinitely elongated until additional mechanisms can lead to rupture. It is suggested that electric fields can be used to enhance such phenomena.

Elastic recovery of immiscible blends 1. Analysis after steady state shear flow

1999 ◽  
Vol 38 (1) ◽  
pp. 65-72 ◽  
Author(s):  
I. Vinckier ◽  
P. Moldenaers ◽  
J. Mewis
Keyword(s):  
Steady State ◽  
Shear Flow ◽  
Elastic Recovery ◽  
Immiscible Blends

Mechanical Enhancement of Cellulose Nanofibril (CNF) Films Through the Addition of Water-soluble Polymers

2021 ◽  
Author(s):  
Endrina Stefani Forti ◽  
Sami M El Awad ◽  
Xin Y Ng ◽  
Whirang Cho ◽  
Gregory T Schueneman ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Cellulose Nanofibrils ◽  
Water Soluble ◽  
Oxidized Cellulose ◽  
Solution Casting ◽  
Toughening Mechanism ◽  
Water Soluble Polymers ◽  
Soluble Polymers ◽  
Carboxylate Groups ◽  
Cnf Films

Abstract In this work, water-soluble polymers were screened through solution casting and polyvinyl alcohol (PVA) and poly(2-ethyl-2-oxazoline) (PEOX) were found as reinforcement agents for cellulose nanofibrils (CNFs) films. Mechanical property increases of 99% in elastic modulus, 93% in the ultimate tensile strength (UTS) and 134% in the work of failure (WOF) were reported for TEMPO-oxidized cellulose nanofibrils (TOCNF) with 0.44 mmol/g carboxylate groups and 15 wt.% PVA. PEOX had a higher elastic modulus increase of 113%, yet lower UTS and WOF increases were found at 63% and 28%, respectively. Additionally, increases in UTS and elastic modulus were also seen in mechanically fibrillated CNF and TOCNFs with higher carboxylate contents (1.5 mmol/g). The toughening mechanism was attributed to the formation of strong hydrogen bonding between the CNFs and the hydrophilic polymers added. The presence of such mechanisms was indirectly confirmed by tensile testing, zeta potential and rheology.

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