Influence of High Shear Dispersion on the Production of Cellulose Nanofibers by Ultrasound-Assisted TEMPO-Oxidation of Kraft Pulp

Abstract Here, a new pretreatment method has been developed to produce CNFs from micro-fibrillated cellulose (MFC) by supercritical CO 2 pretreatment followed with ball-milling (SCB). MFC was obtained from cotton stalk by chemical purification.Experimental factors were controlled to enhance the properties of SCB-CNF, meanwhile a comparative study was conducted with the method of TEMPO oxidation and microfluid homogenization (TMH). Compared to TMH-CNF, the SCB-CNF has such advantages as Energy saving, high efficiency and environmental protection, indicating a wide application in heat-resistant materials, load materials and other fields. The solid yields of P-MFC after supercritical CO 2 pretreatment gradually decreased together with the temperature and the reaction time. Scanning electron microscope (SEM) images of the SCB-CNF and TMH-CNF show that the morphology of the SCB-CNF was basically acicular but that of the TMH-CNF was mainly soft fibrous. The SCB-CNF is smaller in width and shorter in length, and its size is between CNC and CNF. Thermal gravimetric results suggest that the thermal stability of the SCB-CNF was substantially higher than those of the TMH-CNF. XRD results indicate that the crystallinity showed an initial increasing trend and then declined with increasing temperature and reaction time, and the crystallinity value of SCB-CNF was larger than that of CNFs. The smaller SCB-CNF became rougher and had a larger surface area. High crystallinity make good thermal stability, short and coarse fiber, easier to disperse than CNF, less energy consumption for dispersion, better than 3D mesh. It can be widely used in polymer composites, reinforcing agents, membrane materials and other fields.

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Improving the Creep Resistance of Elektron21 by Adding AlN/Al Nanoparticles Using the High Shear Dispersion Technique

The Minerals, Metals & Materials Series - Magnesium 2021 ◽

10.1007/978-3-030-72432-0_7 ◽

2021 ◽

pp. 57-69

Author(s):

Hong Yang ◽

Yuanding Huang ◽

Karl Ulrich Kainer ◽

Hajo Dieringa

Keyword(s):

Creep Resistance ◽

High Shear ◽

Al Nanoparticles ◽

Shear Dispersion ◽

Dispersion Technique

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Preparation of cellulose nanofibers by TEMPO-oxidation of bleached chemi-thermomechanical pulp for cement applications

Carbohydrate Polymers ◽

10.1016/j.carbpol.2018.09.036 ◽

2019 ◽

Vol 203 ◽

pp. 238-245 ◽

Cited By ~ 12

Author(s):

Mounir El Bakkari ◽

Vivek Bindiganavile ◽

Jose Goncalves ◽

Yaman Boluk

Keyword(s):

Cellulose Nanofibers ◽

Thermomechanical Pulp ◽

Tempo Oxidation

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The Cellulose Nanofibers for Optoelectronic Conversion and Energy Storage

Journal of Nanomaterials ◽

10.1155/2014/654512 ◽

2014 ◽

Vol 2014 ◽

pp. 1-13 ◽

Cited By ~ 2

Author(s):

Yongfeng Luo ◽

Jianxiong Zhang ◽

Xi Li ◽

Chunrong Liao ◽

Xianjun Li

Keyword(s):

Energy Storage ◽

Cellulose Nanofibers ◽

Optoelectronic Device ◽

Nanostructured Material ◽

The Novel ◽

Energy Storage Devices ◽

Tempo Oxidation ◽

Environment Friendly ◽

Storage Devices ◽

Low Thermal Expansion

Cellulose widely exists in plant tissues. Due to the large pores between the cellulose units, the regular paper is nontransparent that cannot be used in the optoelectronic devices. But some chemical and physical methods such as 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) oxidation can be used to improve the pores scale between the cellulose units to reach nanometer level. The cellulose nanofibers (CNFs) have good mechanical strength, flexibility, thermostability, and low thermal expansion. The paper made of these nanofibers represent a kind of novel nanostructured material with ultrahigh transparency, ultrahigh haze, conductivity, biodegradable, reproducible, low pollution, environment friendly and so on. These advantages make the novel nanostructured paper apply in the optoelectronic device possible, such as electronics energy storage devices. This kind of paper is considered most likely to replace traditional materials like plastics and glass, which is attracting widespread attention, and the related research has also been reported. The purpose of this paper is to review CNFs which are applied in optoelectronic conversion and energy storage.

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Scalable Preparation of Cellulose Nanofibers from Office Waste Paper by an Environment-Friendly Method

Polymers ◽

10.3390/polym13183119 ◽

2021 ◽

Vol 13 (18) ◽

pp. 3119

Author(s):

Deyuan Huang ◽

Haoqun Hong ◽

Weilong Huang ◽

Haiyan Zhang ◽

Xiaobin Hong

Keyword(s):

Electron Microscopy ◽

Light Transmission ◽

Alkali Treatment ◽

Cellulose Nanofibers ◽

Waste Paper ◽

Narrow Particle Size Distribution ◽

Cellulose Content ◽

Tempo Oxidation ◽

20 Nm ◽

Bleaching Treatment

Waste paper is often underutilized as a low-value recyclable resource and can be a potential source of cellulose nanofibers (CNFs) due to its rich cellulose content. Three different processes, low acid treatment, alkali treatment and bleaching treatment, were used to pretreat the waste paper in order to investigate the effect of different pretreatments on the prepared CNFs, and CNFs obtained from bleached pulp boards were used as control. All sample fibers were successfully prepared into CNFs by 2,2,6,6-tetramethyl-piperidine-1-oxyl (TEMPO) oxidation. It was quite obvious that the bleached CNFs samples showed dense fibrous structures on a scanning electron microscopy (SEM), while needle-like fibers with width less than 20 nm were observed on a transmission electron microscopy (TEM). Meanwhile, the bleaching treatment resulted in a 13.5% increase in crystallinity and a higher TEMPO yield (e.g., BCNF, 60.88%), but a decrease in thermal stability. All pretreated CNFs samples showed narrow particle size distribution, good dispersion stability (zeta potential less than −29.58 mV), good light transmission (higher than 86.5%) and low haze parameters (lower than 3.92%). This provides a good process option and pathway for scalable production of CNFs from waste papers.

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A Fast-Response Electroactive Actuator Based on TEMPO-Oxidized Cellulose Nanofibers

Smart Materials and Structures ◽

10.1088/1361-665x/ac4037 ◽

2021 ◽

Author(s):

Yan Huang ◽

Fang Wang ◽

Liying Qian ◽

Xiuhua Cao ◽

Beihai He ◽

...

Keyword(s):

Layered Structure ◽

Self Assembly ◽

Biomedical Applications ◽

Low Voltage ◽

Cellulose Nanofibers ◽

Conductive Polymer ◽

Fast Response ◽

Tempo Oxidation ◽

Ion Migration ◽

High Mechanical Strength

Abstract Cellulose-based electroactive actuators are promising candidates for biomimetic robots and biomedical applications due to their lightweight, high mechanical strength, and natural abundance. However, cellulose-based electroactive actuators exhibit lower actuation performance than traditional conductive polymer actuators. This work reports a fast-response cellulose-based electroactive actuator based on 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidized nanocellulose (TOCNF) film with layered structure fabricated by evaporation, and gold electrodes prepared by ion sputtering. The residual ions during the TEMPO oxidation process and the layered structure due to self-assembly accelerate the ion migration efficiency in actuators. The proposed actuator can reach a tip displacement of 32.1 mm at a voltage of 10 V and deflect 60° in 5 s. After applying a reverse 10 V voltage, the actuator can also be quickly deflected (42.5 mm). In addition, the actuator also shows high electrical actuation performance at low voltage (5 V). The excellent electroactive performance of as-prepared TOCNF/Au enables the feasibility to be applied to actuators.

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