scholarly journals Cellulose nanofibrils manufactured by various methods with application as paper strength additives

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jinsong Zeng ◽  
Zhanting Zeng ◽  
Zheng Cheng ◽  
Yu Wang ◽  
Xiaojun Wang ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Cellulose Nanofibrils ◽  
Morphological Characteristics ◽  
Paper Strength ◽  
Recycled Paper ◽  
Factors Affecting ◽  
Practical Applications ◽  
Force Microscopy ◽  
Atomic Force ◽  
Cnf Films

AbstractRecycled paper and some hardwood paper often display poorer mechanical properties, which hinder its practical applications and need to be addressed. In this work, cellulose nanofibrils (CNFs) obtained by a combined process of enzymatic hydrolysis and grinding (EG-CNFs), grinding and microfluidization (GH-CNFs) or TEMPO-mediated oxidation and grinding (TE-CNFs) were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Moreover, CNFs were made into films on which some characterizations including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and UV–Vis transmittance spectroscopy were implemented. Results showed that CNF fibrillation was promoted as times of passes increased in microfluidization, and CNFs pretreated by enzyme possessed shorter length. Crystallinity of CNFs was related to CNF manufacturing methods, while CNF films’ transparency was correlated to CNF diameter distributions. Moreover, CNFs were applied with different dosages on recycled and hardwood paper. Lengths of CNFs, strength of CNF network, and pulp properties were critical factors affecting the mechanical strength of CNFs-enhanced paper. GH-CNFs showed better strengthened effect on tensile strength of paper than TE-CNFs and EG-CNFs. The best overall improvement was achieved at GH-CNF10 dosage of 5.0 wt% on hardwood paper. The increment of tensile index, burst index, and folding endurance were 108.32%, 104.65%, and 600%, respectively. This work aims to find out the relationship between production methods and morphologies of CNFs and how the morphological characteristics of CNFs affecting the mechanical performance of paper when they are added as strength additives.

Preparation of Cellulose Nanofibrils by High-Pressure Homogenizer and Zein Composite Films

2013 ◽  
Vol 829 ◽  
pp. 534-538 ◽  
Author(s):  
Alireza Shakeri ◽  
Sattar Radmanesh
Keyword(s):  
Atomic Force Microscopy ◽  
High Pressure ◽  
Food Packaging ◽  
Cellulose Nanofibrils ◽  
Composite Films ◽  
Average Diameter ◽  
Nanocomposite Films ◽  
Force Microscopy ◽  
Atomic Force ◽  
High Pressure Homogenizer

Cellulose nanofibrils ( NF ) have several advantages such as biodegradability and safety toward human health. Zein is a biodegradable polymer with potential use in food packaging applications. It appears that polymer nanocomposites are one of the most promising applications of zein films. Cellulose NF were prepared from starting material Microcrystalline cellulose (MCC) by an application of a high-pressure homogenizer at 20,000 psi and treatment consisting of 15 passes. Methods such as atomic force microscopy were used for confirmation of nanoscale size production of cellulose. The average diameter 45 nm were observed. Zeincellulose NF nanocomposite films were prepared by casting ethanol suspensions of Zein with different amounts of cellulose NF in the 0% to 5%wt. The nanocomposites were characterized by using Fourier transform infrared spectroscopy ( FTIR ), Atomic force microscopy ( AFM ) and X-ray diffraction ( XRD ) analysis. From the FTIR spectra the various groups present in the Zein blend were monitored. The homogeneity, morphology and crystallinity of the blends were ascertained from the AFM and XRD data, respectively. The thermal resistant of the zein nanocomposite films improved as the nanocellulose content increased. These obtained materials are transparent, flexible and present significantly better physical properties than the corresponding unfilled Zein films.

High-Speed Atomic Force Microscopy Reveals Factors Affecting the Processivity of Chitinases during Interfacial Enzymatic Hydrolysis of Crystalline Chitin

ACS Catalysis ◽  
2020 ◽  
Vol 10 (22) ◽  
pp. 13606-13615
Author(s):  
Mingbo Qu ◽  
Takahiro Watanabe-Nakayama ◽  
Shaopeng Sun ◽  
Kenichi Umeda ◽  
Xiaoxi Guo ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Enzymatic Hydrolysis ◽  
High Speed ◽  
Factors Affecting ◽  
Force Microscopy ◽  
Atomic Force ◽  
Hydrolysis Of

scholarly journals The Quality Assessment of Stored Red Blood Cells Probed Using Atomic-Force Microscopy

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
I. M. Lamzin ◽  
R. M. Khayrullin
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Morphological Characteristics ◽  
High Increase ◽  
Mean Values ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Mean ◽  
The Moment

At the moment the suitability of stored red blood cells (sRBC) for transfusion is checked by routine methods such as haemoglobin estimation and the level of haemolysis. These methods cannot characterize directly the quality of the membranes of sRBC. The aim of this work is to assess the quality of sRBC based on such criteria as the membrane’s stiffness and the size and the form of sRBC. Materials and Methods. We have investigated 5 series of dry cytosmears of the sRBC which had been kept in blood bank in a period from 1 to 35 days. After AFM imaging, in every specimen, 5 RBC were chosen at random; the diameter, the height, and the stiffness were measured on each of them. Results. The present study shows high increase of the mean values of YM and height of RBC after 35 days of storage and decrease of the mean values of their diameter. Conclusion. Statistically significant high increase of the mean values of YM indicates the decrease of the elasticity of the cells in the course of storing of the RBC. This parameter along with the morphological characteristics can be used as criterion for assessment of applicability of the sRBC for blood transfusion.

scholarly journals Cellulose-Cyclodextrin Co-Polymer for the Removal of Cyanotoxins on Water Sources

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2075
Author(s):  
Diego Gomez-Maldonado ◽  
Iris Beatriz Vega Erramuspe ◽  
Ilari Filpponen ◽  
Leena-Sisko Johansson ◽  
Salvatore Lombardo ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Cellulose Nanofibrils ◽  
Human Consumption ◽  
Nutrient Runoff ◽  
Force Microscopy ◽  
Atomic Force ◽  
Safe Limits ◽  
Ft Ir ◽  
Recreational Use

With increasing global water temperatures and nutrient runoff in recent decades, the blooming season of algae lasts longer, resulting in toxin concentrations that exceed safe limits for human consumption and for recreational use. From the different toxins, microcystin-LR has been reported as the main cyanotoxin related to liver cancer, and consequently its abundance in water is constantly monitored. In this work, we report a methodology for decorating cellulose nanofibrils with β-cyclodextrin or with poly(β-cyclodextrin) which were tested for the recovery of microcystin from synthetic water. The adsorption was followed by Quartz Crystal Microbalance with Dissipation monitoring (QCM-D), allowing for real-time monitoring of the adsorption behavior. A maximum recovery of 196 mg/g was obtained with the modified by cyclodextrin. Characterization of the modified substrate was confirmed with Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Photoelectron Spectroscopy (XPS), Thermogravimetric Analysis (TGA), and Atomic Force Microscopy (AFM).

Rubber–rubber blends: A critical review

2019 ◽  
Vol 36 (3) ◽  
pp. 196-242
Author(s):  
Abitha Vayyaprontavida Kaliyathan ◽  
KM Varghese ◽  
A Sreekumaran Nair ◽  
Sabu Thomas
Keyword(s):  
Scientific Literature ◽  
Significant Proportion ◽  
Morphological Characterization ◽  
Factors Affecting ◽  
Rubber Blends ◽  
Force Microscopy ◽  
Rubber Blend ◽  
Advantages And Disadvantages ◽  
Atomic Force

The blending of different rubbers is one of the effective methods to achieve required performance properties in their final products. This article reviews the thermodynamic considerations of rubber–rubber blends and their filled systems. Factors affecting the rubber blend morphology (i.e. distribution mechanism of fillers, curatives and other compounding ingredients) and preparation techniques for rubber–rubber blends emphasizing their advantages and disadvantages are well discussed in this review. Microscopy is the field of interest to all material scientists. In the case of rubber blends, microscopy is an essential tool in order to understand the morphology, that is, size, shape and distribution of phases and filler particles in the rubber–rubber blend. In this review, selected scientific reports based on optical microscopy, electron microscopy and atomic force microscopy in rubber–rubber blends are discussed. Rubber material is a complex macromolecule; it has significant proportion of fillers, processing aids and curing agents; therefore, only a very few studies have been reported on the microscopic aspects of filled rubber–rubber blends. In particular, influence of rubber blend composition, fillers (micro and nano length scales) and processing additives on the morphology of rubber blends systems has not been systematically reviewed and discussed in the scientific literature. Therefore, in the present scenario, this review was thought of, which deals with the essential background to rubber–rubber blends, miscibility and morphological characterization of various rubber blend systems by microscopy. It is very important to add that although there is scattered information on these aspects in the scientific literature, to date a comprehensive review has not been published. The pros, cons, artefacts and the new challenges on the use of microscopy for the characterization of rubber–rubber blends are also discussed here.

scholarly journals Practical applications of atomic force microscopy in biomedicine

STEMedicine ◽  
2020 ◽  
Vol 1 (2) ◽  
pp. e15
Author(s):  
Nicola Galvanetto
Keyword(s):  
Atomic Force Microscopy ◽  
Drug Discovery ◽  
Membrane Proteins ◽  
Biological Samples ◽  
Live Imaging ◽  
Proof Of Concept ◽  
Living Matter ◽  
Practical Applications ◽  
Force Microscopy ◽  
Atomic Force

The last thirty years of progress of atomic force microscopy (AFM) applied to living matter is reviewed with a focus on potential uses in drug discovery or screening of patient samples. AFM-based technologies are still at Proof of Concept level - or below, however, they are particularly promising for i) live imaging of unlabeled membrane proteins and ii) nanomechanical screening of biological samples, e.g. cancer biopsies.

scholarly journals Photoelectrical properties investigated on individual Si nanowires and their size dependence

2020 ◽  
Author(s):  
Xiaofeng Hu ◽  
Shujie Li ◽  
Zuimin Jiang ◽  
Xinju Yang
Keyword(s):  
Barrier Height ◽  
Size Dependence ◽  
Laser Intensity ◽  
Electrostatic Force ◽  
Si Nanowires ◽  
Practical Applications ◽  
Force Microscopy ◽  
Photoelectrical Properties ◽  
Atomic Force ◽  
Different Diameters

Abstract Periodically ordered arrays of vertically aligned Si nanowires (Si NWs) are successfully fabricated with controllable diameters and lengths. Their photoconductive properties are investigated by photoconductive atomic force microscopy (PCAFM) on individual nanowires. The results show that the photocurrent of Si NWs increases significantly with the laser intensity, indicating that Si NWs have good photoconductance and photoresponse capability. This photo-enhanced conductance can be attributed to the photo-induced Schottky barrier change, confirmed by I-V curve analyses. On the other hand, electrostatic force microscopy (EFM) results indicate that a large number of photo-generated charges are trapped in Si NWs under laser irradiation, leading to the lowering of barrier height. Moreover, the size dependence of photoconductive properties is studied on Si NWs with different diameters and lengths. It is found that the increasing magnitude of photocurrent with laser intensity is greatly relevant to the nanowires’ diameter and length. Si NWs with smaller diameters and shorter lengths display better photoconductive properties, which agrees well with the size-dependent barrier height variation induced by photo-generated charges. With optimized diameter and length, great photoelectrical properties are achieved on Si NWs. Overall, in this study the photoelectrical properties of individual Si NWs are systematically investigated by PCAFM and EFM, providing important information for the optimization of nanostructures for practical applications.

scholarly journals Comparative analysis of the dust retention capacity and leaf microstructure of 11 Sophora japonica clones

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0254627
Author(s):  
Jie Yu ◽  
Li-Ren Xu ◽  
Chong Liu ◽  
Yong-Tan Li ◽  
Xin-Bo Pang ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Morphological Characteristics ◽  
Dust Deposition ◽  
Sophora Japonica ◽  
Retention Capacity ◽  
Force Microscopy ◽  
Unit Leaf ◽  
Atomic Force ◽  
Total Particle ◽  
Dust Retention

We used fresh leaves of Sophora japonica L. variety ‘Qingyun 1’ (A0) and 10 superior clones of the same species (A1–A10) to explore leaf morphological characteristics and total particle retention per unit leaf area under natural and artificial simulated dust deposition treatments. Our objectives were to explore the relationship between the two methods and to assess particle size distribution, X-ray fluorescence (XRF) heavy metal content, and scanning electron and atomic force microscopy (SEM and AFM) characteristics of leaf surface microstructure. Using the membership function method, we evaluated the dust retention capacity of each clone based on the mean degree of membership of its dust retention index. Using correlation analysis, we selected leaf morphological and SEM and AFM indices related significantly to dust retention capacity. Sophora japonica showed excellent overall dust retention capacity, although this capacity differed among clones. A5 had the strongest overall retention capacity, A2 had the strongest retention capacity for PM2.5, A9 had the strongest retention capacity for PM2.5–10, A0 had the strongest retention capacity for PM>10, and A2 had the strongest specific surface area (SSA) and heavy metal adsorption capacity. Overall, A1 had the strongest comprehensive dust retention ability, A5 was intermediate, and A7 had the weakest capacity. Certain leaf morphological and SEM and AFM characteristic indices correlated significantly with the dust retention capacity.

scholarly journals Influence of Ultraviolet Radiation Exposure Time on Styrene-Ethylene-Butadiene-Styrene (SEBS) Copolymer

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 862 ◽  
Author(s):  
Daniel Garcia-Garcia ◽  
José Enrique Crespo-Amorós ◽  
Francisco Parres ◽  
María Dolores Samper
Keyword(s):  
Surface Energy ◽  
Ultraviolet Radiation ◽  
Mechanical Performance ◽  
Polymer Materials ◽  
Attenuated Total Reflectance ◽  
Force Microscopy ◽  
Atomic Force ◽  
Ultraviolet Radiation Exposure ◽  
Physical Changes ◽  
Butadiene Styrene

The effect of ultraviolet radiation on styrene-ethylene-butadiene-styrene (SEBS) has been studied at different exposures times in order to obtain a better understanding of the mechanism of ageing. The polymer materials were mechanically tested and then their surfaces were analyzed using a scanning electron microscope (SEM) and atomic force microscopy (AFM). Moreover, the optical analysis of contact angle (OCA) was used to evaluate the surface energy (γs) and the yellowing index (YI) and attenuated total reflectance infrared spectroscopy (ATR–FTIR) were used to observe structural and physical changes in aging SEBS. The results obtained for the SEBS, in relation to the duration of exposure, showed superficial changes that cause a decrease in the surface energy (γs) and, therefore, a decrease in surface roughness. This led to a reduction in mechanical performance, decreasing the tensile strength by about 50% for exposure times of around 200 h.

Three-Dimensional Nanostructures with Biocidal Activity Created on a Siloxane-Containing Copolyimide Film

2015 ◽  
Vol 638 ◽  
pp. 98-103 ◽  
Author(s):  
Iuliana Stoica ◽  
Andreea Irina Barzic ◽  
Magdalena Aflori ◽  
Camelia Hulubei ◽  
Valeria Harabagiu ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Antimicrobial Properties ◽  
Morphological Characteristics ◽  
Interfacial Area ◽  
Average Roughness ◽  
Force Microscopy ◽  
Atomic Force ◽  
Before And After ◽  
Reactive Groups ◽  
Predominant Orientation

Surface morphological characteristics of a copolyimide film prepared from a fluorine-based dianhydride combined with an aliphatic siloxane-based diamine and an aromatic containing ether linkages one, were studied before and after oxigen plasma treatment using atomic force microscopy (AFM). The three-dimensional texture parameters calculated from the AFM data have highlighted a more pronounced surface morphology (higher average roughness and developed interfacial area ratio), improved bearing properties and no predominant orientation, as the plasma exposure time was increased from 6 to 10 minutes, using the same power (40 W). The reactive groups generated on the binding surface have facilitated the interaction with a biocidal agent, such as silver nitrate. This creates silver-containing nanoparticles, of about 120-150 nm, uniformly distributed on the copolymer surface, with a density of 10±2 particles/μm2. The functionalization with the biocidal agent of the flourinated copolyimide surface was conducted for testing its antimicrobial properties, namely the inhibition/destruction of Escherichia coli bacterium.

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