scholarly journals Characterization of aqueous cellulose nanofiber dispersions from microscopy movie data of Brownian particles by trajectory analysis

2019 ◽  
Vol 1 (1) ◽  
pp. 421-429 ◽  
Author(s):  
Reiji Motohashi ◽  
Itsuo Hanasaki

Cellulose nanofibers (CNFs) are not directly visible by microscopes when dispersed in water, but the dynamical characteristics of suspended colloidal particles tells us the texture as well as the rheological properties of CNF dispersions beyond the viscosity.

2020 ◽  
Vol 14 (2) ◽  
pp. 203-208 ◽  
Author(s):  
Xiuqiang Zhang ◽  
Suxia Ren ◽  
Xiaofeng He ◽  
Lili Dong ◽  
Wei Bai ◽  
...  

Zinc oxide (ZnO)/cellulose nanofiber (CNF) nanocomposite films were prepared using cellulose nanofibers and ZnO nanoparticles. First, suspensions of CNF and ZnO mixtures were blended with different CNF/ZnO ratios; then, the mixtures were stirred, homogenized, filtered, and hot pressed to form nanofilms with various ZnO weight ratios (0–50 wt%). Rheological tests showed that the CNF shear thinning behavior was not affected by the addition of ZnO. X-ray diffraction and scanning electron microscopy studies proved the existence of ZnO nanoparticles in the nanocomposite films. Thermogravimetric results indicated that the presence of ZnO had almost no effect on the thermal properties of the composite. As the ZnO content increased, the tensile strength and strain-to-failure rate decreased. In comparison with neat CNF nanofilms, the nanocomposite films showed greater antimicrobial ability against Gram-positive Staphylococcus aureus due to the presence of ZnO nanoparticles, allowing the CNF/ZnO films to be used in some targeted biomedical applications.


1989 ◽  
Vol 177 ◽  
Author(s):  
D. J. Pine ◽  
D. A. Weitz ◽  
D. J. Durian ◽  
P. N. Pusey ◽  
R. J. A. Tough

ABSTRACTOn a short time scale, Brownian particles undergo a transition from initially ballistic trajectories to diffusive motion. Hydrodynamic interactions with the surrounding fluid lead to a complex time dependence of this transition. We directly probe this transition for colloidal particles by measuring the autocorrelation function of multiply scattered light and observe the effects of the slow power-law decay of the velocity autocorrelation function.


2021 ◽  
Vol 154 (16) ◽  
pp. 164901
Author(s):  
José Martin-Roca ◽  
Raul Martinez ◽  
Lachlan C. Alexander ◽  
Angel Luis Diez ◽  
Dirk G. A. L. Aarts ◽  
...  

2021 ◽  
Vol 27 ◽  
pp. 100180
Author(s):  
A.M. Serpa Guerra ◽  
C. Gómez Hoyos ◽  
J.A. Velásquez-Cock ◽  
P. Gañán Rojo ◽  
A. Eceiza ◽  
...  

2021 ◽  
Vol 22 (11) ◽  
pp. 5781
Author(s):  
Janarthanan Supramaniam ◽  
Darren Yi Sern Low ◽  
See Kiat Wong ◽  
Loh Teng Hern Tan ◽  
Bey Fen Leo ◽  
...  

Cellulose nanofibers (CNF) isolated from plant biomass have attracted considerable interests in polymer engineering. The limitations associated with CNF-based nanocomposites are often linked to the time-consuming preparation methods and lack of desired surface functionalities. Herein, we demonstrate the feasibility of preparing a multifunctional CNF-zinc oxide (CNF-ZnO) nanocomposite with dual antibacterial and reinforcing properties via a facile and efficient ultrasound route. We characterized and examined the antibacterial and mechanical reinforcement performances of our ultrasonically induced nanocomposite. Based on our electron microscopy analyses, the ZnO deposited onto the nanofibrous network had a flake-like morphology with particle sizes ranging between 21 to 34 nm. pH levels between 8–10 led to the formation of ultrafine ZnO particles with a uniform size distribution. The resultant CNF-ZnO composite showed improved thermal stability compared to pure CNF. The composite showed potent inhibitory activities against Gram-positive (methicillin-resistant Staphylococcus aureus (MRSA)) and Gram-negative Salmonella typhi (S. typhi) bacteria. A CNF-ZnO-reinforced natural rubber (NR/CNF-ZnO) composite film, which was produced via latex mixing and casting methods, exhibited up to 42% improvement in tensile strength compared with the neat NR. The findings of this study suggest that ultrasonically-synthesized palm CNF-ZnO nanocomposites could find potential applications in the biomedical field and in the development of high strength rubber composites.


2018 ◽  
Vol 26 (10) ◽  
pp. 13239 ◽  
Author(s):  
David B. Ruffner ◽  
Fook Chiong Cheong ◽  
Jaroslaw M. Blusewicz ◽  
Laura A. Philips

2017 ◽  
Vol 754 ◽  
pp. 135-138
Author(s):  
Hitoshi Takagi ◽  
Antonio Norio Nakagaito ◽  
Yuya Sakaguchi

The presence of nanoscale cellulosic fiber; namely cellulose nanofiber, increases year by year because the mechanical and physical properties are believed to be comparable to those of common glass fibers. On the other hand, most of the reported strength data for the cellulose nanofiber-reinforced polymeric composite materials was not as high as expected. In order to obtain high-strength cellulose nanofiber-reinforced polymer composites, we tried to optimize the fiber orientation of cellulose nanofibers in poly (vinyl alcohol)-based polymer matrix by using a repeated mechanical stretching treatment. The fiber orientation of cellulose nanofibers in the poly (vinyl alcohol) matrix can be modified by changing the total amount of stretching strain applied during the multiple stretching treatments. The degree of fiber alignment was directly evaluated by observing the cellulose nanofibers on the sample surface with a digital microscope. The efficacy of proposed nanofiber alignment control has been explored experimentally and theoretically. The tensile strength and modulus of the cellulosic nanocomposites after applying the multiple stretching treatments increased by approximately 80% and 40% respectively, as compared with those of the untreated nanocomposites.


1997 ◽  
Vol 41 (2) ◽  
pp. 177-195 ◽  
Author(s):  
Sejin Han ◽  
K. K. Wang ◽  
C. A. Hieber ◽  
C. Cohen

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