Aspect Ratio of TEMPO-Oxidized Nanocellulose and Rheological Analysis of Aqueous Suspensions

Yamagata, Yuriko; Suga, Kotaro; Nakano, Yuki; Takasaki, Yuichi; Miyamoto, Keisuke

doi:10.1678/rheology.48.207

Cited by 6 publications

(6 citation statements)

References 19 publications

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“…Thus, even for the sample with 20 collisions (Vn = 32.7 %), it is suggested that the nanosized fibers 172 physically entangled to form a three-dimensional network structure. The storage modulus G' of the sample with 30 collisions (Vn = 47.4 %) was about 10 3 Pa, which was similar to that of the 1.5 wt% suspension of CNF (fiber length: 174 827 nm, aspect ratio: 243) prepared by the TEMPO oxidation (Yamagata 2020) and the 2 % suspension of 175 microfibrillated cellulose (MFC) prepared by high-pressure homogenization by Iotti et al (2011).…”

Section: Viscoelastic Behaviors Of Cnf Suspensionssupporting

confidence: 52%

“…CNFs prepared from various types of cellulose sources using the above-mentioned process have been deployed in 80 various industries due to their value-added properties, and studies have been conducted focusing on the rheological properties of the CNF suspensions (Bercea and Navard 2000;Boluk et al 2011;Charani et al 2013;Iotti et al 2011;Iwamoto et al 2014;Naderi et al 2014;Pääkkö et al 2007;Tanaka et al 2020;Yamagata and Miyamoto 2021;Yamagata et al 2020). In other words, it is important to understand how to control the rheological behavior of the CNF suspensions in order to fully exploit the potential of the material.…”

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confidence: 99%

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Rheological and Rheo-optical Behaviors of Nanocellulose Suspensions Containing Unfibrillated Fibers

Yamagata¹,

Niinobe²,

Suga³

et al. 2021

Preprint

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Cellulose nanofibers (CNFs) produced by mechanical processing have a more uneven fiber shape, diameter, and length than those produced by chemical processing. Depending on the manufacturing conditions, CNFs containing insufficient fibrillated fibers may be produced. In order to find practical applications for CNFs containing unfibrillated fibers, it is important to understand how to control the rheological behavior of these systems. In this study, we investigated the relationship between the nanosized volume fraction and the rheological behaviors of CNF suspensions containing unfibrillated fibers prepared by a wet refining system (Water Jet System). The macroscopic structural changes in those suspensions under shear flow were also discussed based on rheo-optic measurements. According to the frequency sweeps of the CNF suspensions, it was found that they were elastic-dominated gels, and the elasticity was attributed to the nanofibers. The elastic moduli increased with the volume fraction of the nanofibers, suggesting that the entanglement of the nanofibers was enhanced. The pseudo-plateau modulus Gp' is proportional to the nanofiber volume fraction, with the constant α = 1.5, suggesting that the entropic elasticity is dominant. The viscosity curves of the CNF suspensions showed a shear thinning behavior, in which the viscosity linearly decreased with the increasing shear rate. From the Rheo-SALS measured at the same time, we found that the aggregates of the nanofibers elongated in the flow direction and deformed into an elliptical shape with the applied shearing. The shape change of the aggregates comprised of the nanofibers became more pronounced with the increased nanofiber volume fraction. However, the effect of the shape change of the aggregates was hardly observed on the viscosity curve. We speculate that this is due to the fact that the unnanosized fibers, which exhibit a Newtonian flow, play a significant role in the flow behavior of the CNF suspensions.

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Section: Viscoelastic Behaviors Of Cnf Suspensionssupporting

confidence: 52%

mentioning

confidence: 99%

Rheological and Rheo-optical Behaviors of Nanocellulose Suspensions Containing Unfibrillated Fibers

Yamagata¹,

Niinobe²,

Suga³

et al. 2021

Preprint

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“…Average length of the S-CNC was estimated using Simha's formula (eq. A3) 20) , describing the relationship between p and [η] of ellipsoids, which were also used in several literature (Table I) 16,19,[21][22][23][24][25][26] . The average length was ~30 % longer than those determined by microscopy.…”

Section: Intrinsic Viscosity Of Nanocellulose Dispersionsmentioning

confidence: 99%

Rheological Properties of Nanocellulose Dispersions in the Dilute Region: Current Understanding and Future Perspectives

Tanaka

2022

J. Soc. Rheol., Jpn

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The current knowledge and prospects for rheological properties of nanocellulose dispersions in a dilute region are presented. It is essential to clarify the rheological properties of dilute nanocellulose dispersions because they represent the properties of nanocellulose. This study highlights intrinsic viscosity and viscoelastic relaxation, which are indicators of average size, size distribution, and flexibility. While the intrinsic viscosity and viscoelastic relaxation of rod-shaped cellulose nanocrystals (CNCs) can be explained by existing theories of polymers, those of cellulose nanofibers (CNFs) are not fully understood because of their kinks and flexibility.

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“…CNFs prepared from various types of cellulose sources using the above-mentioned process have been deployed in various industries due to their value-added properties, and studies have been conducted focusing on the rheological properties of the CNF suspensions (Bercea and Navard 2000;Boluk et al 2011;Charani et al 2013;Iotti et al 2011;Iwamoto et al 2014;Naderi et al 2014;Pääkkö et al 2007;Tanaka et al 2020;Yamagata and Miyamoto 2021;Yamagata et al 2020). In other words, it is important to understand how to control the rheological behavior of the CNF suspensions in order to fully exploit the potential of the material.…”

mentioning

confidence: 99%

“…Therefore, even if the shape and the length distribution of the fibers are the same, the rheological behavior will be different depending on the fiber type. In addition, the viscosity and elastic modulus increase with the nanofiber concentration even if the starting material is the same (Charani et al 2013;Iotti et al 2011;Pääkkö et al 2007;Yamagata et al 2020).…”

mentioning

confidence: 99%

Rheological and rheo-optical behaviors of nanocellulose suspensions containing unfibrillated fibers

山縣¹,

Niinobe

Suga³

et al. 2022

Cellulose

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Cellulose nanofibers (CNFs) produced by mechanical processing have a more uneven fiber shape, diameter, and length than those produced by chemical processing. Depending on the manufacturing conditions, CNFs containing insufficient fibrillated fibers may be produced. In order to find practical applications for CNFs containing unfibrillated fibers, it is important to understand how to control the rheological behavior of these systems. In this study, we investigated the relationship between the nanosized volume fraction and the rheological behaviors of CNF suspensions containing unfibrillated fibers prepared by a wet refining system (Water Jet System). The macroscopic structural changes in those suspensions under shear flow were also discussed based on rheo-optic measurements.According to the frequency sweeps of the CNF suspensions, it was found that they were elastic-dominated gels, and the elasticity was attributed to the nanofibers. The elastic moduli increased with the volume fraction of the nanofibers, suggesting that the entanglement of the nanofibers was enhanced. The pseudo-plateau modulus Gp' is proportional to the nanofiber volume fraction, with the constant  = 1.5, suggesting that the entropic elasticity is dominant.The viscosity curves of the CNF suspensions showed a shear thinning behavior, in which the viscosity linearly decreased with the increasing shear rate. From the Rheo-SALS measured at the same time, we found that the aggregates of the nanofibers elongated in the flow direction and deformed into an elliptical shape with the applied shearing. The shape change of the aggregates comprised of the nanofibers became more pronounced with the increased nanofiber volume fraction. However, the effect of the shape change of the aggregates was hardly observed on the viscosity curve. 3We speculate that this is due to the fact that the unnanosized fibers, which exhibit a Newtonian flow, play a significant role in the flow behavior of the CNF suspensions.

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Aspect Ratio of TEMPO-Oxidized Nanocellulose and Rheological Analysis of Aqueous Suspensions

Cited by 6 publications

References 19 publications

Rheological and Rheo-optical Behaviors of Nanocellulose Suspensions Containing Unfibrillated Fibers

Rheological and Rheo-optical Behaviors of Nanocellulose Suspensions Containing Unfibrillated Fibers

Rheological Properties of Nanocellulose Dispersions in the Dilute Region: Current Understanding and Future Perspectives

Rheological and rheo-optical behaviors of nanocellulose suspensions containing unfibrillated fibers

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