cellulose nanofibrils
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2022 ◽  
Vol 177 ◽  
pp. 114536
Author(s):  
Yachong Zhu ◽  
Yehong Chen ◽  
Chaojun Wu ◽  
Dongmei Yu ◽  
Qijun Ding ◽  
...  

2022 ◽  
Vol 26 ◽  
pp. 101286
Author(s):  
Rajkumar Bandi ◽  
Madhusudhan Alle ◽  
Ramakrishna Dadigala ◽  
Chan-Woo Park ◽  
Song-Yi Han ◽  
...  

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 286
Author(s):  
Ana Kramar ◽  
Francisco Javier González-Benito

In the past decades, cellulose (one of the most important natural polymers), in the form of nanofibers, has received special attention. The nanofibrous morphology may provide exceptional properties to materials due to the high aspect ratio and dimensions in the nanometer range of the nanofibers. The first feature may lead to important consequences in mechanical behavior if there exists a particular orientation of fibers. On the other hand, nano-sizes provide a high surface-to-volume ratio, which can have important consequences on many properties, such as the wettability. There are two basic approaches for cellulose nanofibers preparation. The top-down approach implies the isolation/extraction of cellulose nanofibrils (CNFs) and nanocrystals (CNCs) from a variety of natural resources, whereby dimensions of isolates are limited by the source of cellulose and extraction procedures. The bottom-up approach can be considered in this context as the production of nanofibers using various spinning techniques, resulting in nonwoven mats or filaments. During the spinning, depending on the method and processing conditions, good control of the resulting nanofibers dimensions and, consequently, the properties of the produced materials, is possible. Pulp, cotton, and already isolated CNFs/CNCs may be used as precursors for spinning, alongside cellulose derivatives, namely esters and ethers. This review focuses on various spinning techniques to produce submicrometric fibers comprised of cellulose and cellulose derivatives. The spinning of cellulose requires the preparation of spinning solutions; therefore, an overview of various solvents is presented showing their influence on spinnability and resulting properties of nanofibers. In addition, it is shown how bottom-up spinning techniques can be used for recycling cellulose waste into new materials with added value. The application of produced cellulose fibers in various fields is also highlighted, ranging from drug delivery systems, high-strength nonwovens and filaments, filtration membranes, to biomedical scaffolds.


2022 ◽  
Author(s):  
Chuan Sun ◽  
Guanhui Li ◽  
Jingyu Wang ◽  
Zhiqiang Fang ◽  
Famei Qin ◽  
...  

Abstract To obtain high performance of nanocomposite films made of cellulose nanofibrils (CNFs) and montmorillonites (MMTs), highly ordered nanostructures and abundant interfacial interactions are of extreme importance, especially for CNF film with high MMT content. Here, we tend to unveil the influence of exfoliation degree of MMTs and their interfacial interactions with CNFs on the properties of ensuing nanocomposite films. Monolayer MMTs prefer to form highly ordered nanostructure during water evaporation induced self-assembly. The obtained nanocomposite film with 30 wt% monolayer MMTs exhibits a tensile strength of 132 MPa, a total light transmittance of 90.2% (550nm), and water vapor transmission rate (WVTR) of 41.5 g•mm/m2•day, better than the film made of original bulk MMTs and CNFs (30 MPa strength, 60% transparency, and 78.7 g•mm/m2•day WVTR). Moreover, the physical properties (153 MPa strength and 20.9 g•mm/m2•day WVTR) of nanocomposite film can be further enhanced by constructing ionic interactions between the monolayer MMT and CNF using 0.5 wt% cationic polyethylenimine (PEI). However, as the amount of PEI continues to increase, its performance will be deteriorated dramatically because of the disordered orientation of monolayer MMTs. This work could provide an insight into the fabrication of high performance MMT/CNF nanocomposite film for advanced applications.


2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Thiago Moreira Cruz ◽  
Adriano Reis Prazeres Mascarenhas ◽  
Mário Vanoli Scatolino ◽  
Douglas Lamounier Faria ◽  
Lays Camila Matos ◽  
...  

Abstract The accumulation of petroleum polymers compromises biodiversity and causes environmental problems. Nanocellulose enhances biodegradability and can improve the physical-mechanical performance of materials. The objective was to produce and characterize hybrid films composed of bacterial cellulose (BC) and plant nanocellulose from Eucalyptus (Euc) or Pinus (Pin). Films were produced by the casting method using filmogenic suspensions with different cellulose nanofibrils (CNFs) proportions from both the sources (0, 25, 50, 75 and 100 %). CNFs suspensions were characterized by transmission electron microscopy. The morphology of the films was analyzed using scanning electron microscopy. In addition, the transparency, contact angle, wettability, oil and water vapor barrier and mechanical properties were also evaluated. The contact angles were smaller for films with BC and the wettability was greater when comparing BC with plant CNFs (0.10 °  s − 1 {\text{s}^{-1}} for 75 % Euc/25 % BC and 0.20 °  s − 1 {\text{s}^{-1}} for 25 % Euc/75 % BC). The water vapor permeability (WVP) of the 100 % BC films and the 25 % Euc/75 % BC composition were the highest among the studied compositions. Tensile strength, Young’s modulus and puncture strength decreased considerably with the addition of BC in the films. More studies regarding pre-treatments to purify BC are needed to improve the mechanical properties of the films.


Cellulose ◽  
2022 ◽  
Author(s):  
Maria Luiza Cafalchio de Oliveira ◽  
Seyedmohammad Mirmehdi ◽  
Mário Vanoli Scatolino ◽  
Mario Guimarães Júnior ◽  
Anand Ramesh Sanadi ◽  
...  

Nanomaterials ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 160
Author(s):  
Rongrong Si ◽  
Yehong Chen ◽  
Daiqi Wang ◽  
Dongmei Yu ◽  
Qijun Ding ◽  
...  

In the present study, carboxymethyl cellulose nanofibrils (CMCNFs) with different carboxyl content (0.99–2.01 mmol/g) were prepared via controlling the ratio of monochloroacetic acid (MCA) and sodium hydroxide to Eucalyptus bleached pulp (EBP). CMCFs-PEI aerogels were obtained using the crosslinking reaction of polyethyleneimine (PEI) and CMCNFs with the aid of glutaraldehyde (GA). The effects of pH, contact time, temperature, and initial Cu2+ concentration on the Cu2+ removal performance of CMCNFs-PEI aerogels was highlighted. Experimental data showed that the maximum adsorption capacity of CMCNF30-PEI for Cu2+ was 380.03 ± 23 mg/g, and the adsorption results were consistent with Langmuir isotherm (R2 > 0.99). The theoretical maximum adsorption capacity was 616.48 mg/g. After being treated with 0.05 M EDTA solution, the aerogel retained an 85% removal performance after three adsorption–desorption cycles. X-ray photoelectron spectroscopy (XPS) results demonstrated that complexation was the main Cu2+ adsorption mechanism. The excellent Cu2+ adsorption capacity of CMCNFs-PEI aerogels provided another avenue for the utilization of cellulose nanofibrils in the wastewater treatment field.


LWT ◽  
2022 ◽  
Vol 153 ◽  
pp. 112459
Author(s):  
Huan Zhang ◽  
Xiaojing Tian ◽  
Kai Zhang ◽  
Yuehong Du ◽  
Chen Guo ◽  
...  

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