scholarly journals An Efficient Method for Cellulose Nanofibrils Length Shearing via Environmentally Friendly Mixed Cellulase Pretreatment

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Yuan Chen ◽  
Yuchan He ◽  
Dongbin Fan ◽  
Yanming Han ◽  
Gaiyun Li ◽  
...  
Keyword(s):  
Cellulose Nanofibrils ◽  
Trichoderma Viride ◽  
Cellulose Fibers ◽  
Effective Diameter ◽  
Layer By Layer ◽  
Mechanical Grinding ◽  
Hydrolysis Time ◽  
Sem Images ◽  
Enzymatic Pretreatment ◽  
Cellulase Hydrolysis

Cellulose nanofibrils (CNFs) have potential applications in the development of innovative materials and enhancement of conventional materials properties. This paper focused on the mixed cellulase hydrolysis with major activity of exoglucanase and endoglucanase on the cellulose length shearing. By the cooperation of two-step production route, including (1) enzymatic pretreatment using cellulase fromTrichoderma virideand (2) mechanical grinding twice, a shorter cellulose nanofiber was fabricated. The influence of enzymatic charge and hydrolysis time on cellulose fibers was analyzed by using scanning electron microscopy (SEM), Fourier Transform Infrared Spectrometer (FTIR), and X-ray diffractometer (XRD). SEM images revealed that the surface morphology change, effective diameter sharpening, and length shearing of cellulose fibers are as a result of cellulase hydrolysis. The XRD suggested that the cellulase acted on the amorphous regions more strongly than the crystalline domains during layer-by-layer hydrolysis. The enzymatic charge and hydrolysis time significantly affected the yields and hydrolysis products concentration. The enzymatic pretreatment assisted mechanical grinding could improve the uniformity of CNF and helped to obtain CNF with exact length according to the requirement for special applications.

Facile preparation of nanofiller-paper using mixed office paper without deinking

TAPPI Journal ◽  
2015 ◽  
Vol 14 (3) ◽  
pp. 167-174 ◽  
Author(s):  
QIANQIAN WANG ◽  
J.Y. ZHU
Keyword(s):  
Cellulose Nanofibrils ◽  
Ash Content ◽  
Raw Material ◽  
Mechanical Grinding ◽  
Microscope Imaging ◽  
Facile Preparation ◽  
Electron Microscope Imaging ◽  
Thermal Stability Of ◽  
Scanning Electron ◽  
Office Paper

Mixed office paper (MOP) pulp without deinking with an ash content of 18.1 ± 1.5% was used as raw material to produce nanofiller-paper. The MOP pulp with filler was mechanically fibrillated using a laboratory stone grinder. Scanning electron microscope imaging revealed that the ground filler particles were wrapped by cellulose nanofibrils (CNFs), which substantially improved the incorporation of filler into the CNF matrix. Sheets made of this CNF matrix were densified due to improved bonding. Specific tensile strength and modulus of the nanofiller-paper with 60-min grinding reached 48.4 kN·m/kg and 8.1 MN·m/kg, respectively, approximately 250% and 200% of the respective values of the paper made of unground MOP pulp. Mechanical grinding duration did not affect the thermal stability of the nanofiller-paper.

scholarly journals Layer-by-Layer Spray-Coating of Cellulose Nanofibrils and Silver Nanoparticles for Hydrophilic Interfaces

2021 ◽  
Author(s):  
Qing Chen ◽  
Calvin J. Brett ◽  
Andrei Chumakov ◽  
Marc Gensch ◽  
Matthias Schwartzkopf ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Cellulose Nanofibrils ◽  
Spray Coating ◽  
Layer By Layer

Effect of Different Heat Treatments on Mechanical Properties of Laser Sintered Additive Manufactured Parts

2017 ◽  
Author(s):  
Sagar Sarkar ◽  
Cheruvu Siva Kumar ◽  
Ashish Kumar Nath
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Yield Strength ◽  
Tensile Strain ◽  
Wear Loss ◽  
Layer By Layer ◽  
Solution Annealing ◽  
Wear Properties ◽  
Sem Images ◽  
Wide Range

One of the most popular additive manufacturing processes is laser based direct metal laser sintering process which enables us to make complex three dimensional parts directly from CAD models. Due to layer by layer formation, parts built in this process tend to be anisotropic in nature. Suitable heat treatment can reduce this anisotropic behaviour by changing the microstructure. Depending upon the applications, a wide range of mechanical properties can be achieved between 482–621° C temperature for precipitation-hardened stainless steels. In the present study effect of different heat treatment processes, namely solution annealing, ageing and overaging, on tensile strength, hardness and wear properties has been studied in detail. Suitable metallurgical and mechanical characterization techniques have been applied wherever required, to support the experimental observations. Results show H900 condition gives highest yield strength and lowest tensile strain at break whereas solution annealing gives lowest yield strength and as-built condition gives highest tensile strain at break. SEM images show that H900 and H1150 condition produces brittle and ductile morphology respectively which in turn gives highest and lowest hardness value respectively.XRD analysis shows presence of austenite phases which can increase hardness at the cost of ductility. Average wear loss for H900 condition is highest whereas it is lowest for solution annealed condition. Further optical and SEM images have been taken to understand the basic wear mechanism involved.

Carbon Nanotube Reinforced Fused Deposition Modeling Using Microwave Irradiation

2016 ◽  
Author(s):  
Meng Zhang ◽  
Xiaoxu Song ◽  
Weston Grove ◽  
Emmett Hull ◽  
Z. J. Pei ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Additive Manufacturing ◽  
Microwave Irradiation ◽  
Computer Aided Design ◽  
Fused Deposition Modeling ◽  
Layer By Layer ◽  
Sem Images ◽  
Fused Deposition ◽  
Deposition Modeling

Additive manufacturing (AM) is a class of manufacturing processes where material is deposited in a layer-by-layer fashion to fabricate a three-dimensional part directly from a computer-aided design model. With a current market share of 44%, thermoplastic-based additive manufacturing such as fused deposition modeling (FDM) is a prevailing technology. A key challenge for AM parts (especially for parts made by FDM) in engineering applications is the weak inter-layer adhesion. The lack of bonding between filaments usually results in delamination and mechanical failure. To address this challenge, this study embedded carbon nanotubes into acrylonitrile butadiene styrene (ABS) thermoplastics via a filament extrusion process. The vigorous response of carbon nanotubes to microwave irradiation, leading to the release of a large amount of heat, is used to melt the ABS thermoplastic matrix adjacent to carbon nanotubes within a very short time period. This treatment is found to enhance the inter-layer adhesion without bulk heating to deform the 3D printed parts. Tensile and flexural tests were performed to evaluation the effects of microwave irradiation on mechanical properties of the specimens made by FDM. Scanning electron microscopic (SEM) images were taken to characterize the fracture surfaces of tensile test specimens. The actual carbon nanotube contents in the filaments were measured by conducting thermogravimetric analysis (TGA). The effects of microwave irradiation on the electrical resistivity of the filament were also reported.

Effect of Surface Grafting-Modified on Structure and Property of Cellulose Fibers

2012 ◽  
Vol 627 ◽  
pp. 43-48
Author(s):  
Shu Hua Wang ◽  
Jin Ming Dai ◽  
Hu Sheng Jia ◽  
Bing She Xu
Keyword(s):  
Cellulose Fibers ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Wet Strength ◽  
Structure And Property ◽  
Chemically Modified ◽  
Crosslinking Process ◽  
Acrylamide Polymerization ◽  
Modified Cellulose ◽  
Effect Of Surface

Cellulose fibers were chemically modified on surface by acrylamide polymerization and glutaraldehyde crosslinking. The chemical and morphological structures of modified cellulose fibers were investigated with X-ray diffraction, FTIR spectra, and scanning electron microscopy (SEM). The crystalline conformations of the cellulose fibers were slightly changed in polymerization and crosslinking process. The wet strength of modified cellulose fibers was improved. Appreciable difference between the surfaces of native and modified cellulose fibers was observed from SEM images.

scholarly journals Structure and Properties of Polylactic Acid Biocomposite Films Reinforced with Cellulose Nanofibrils

Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3306
Author(s):  
Qianqian Wang ◽  
Chencheng Ji ◽  
Jianzhong Sun ◽  
Qianqian Zhu ◽  
Jun Liu
Keyword(s):  
Polylactic Acid ◽  
Cellulose Nanofibrils ◽  
Nitrogen Atmosphere ◽  
Scanning Calorimetry ◽  
Enzymatic Pretreatment ◽  
Thermogravimetric Analyzer ◽  
Degradation Temperature ◽  
Biocomposite Films ◽  
Renewable Feedstock ◽  
Vis Spectroscopy

Polylactic acid (PLA) is one of the most promising biodegradable and recyclable thermoplastic biopolymer derived from renewable feedstock. Nanocellulose reinforced PLA biocomposites have received increasing attention in academic and industrial communities. In the present study, cellulose nanofibrils (CNFs) was liberated by combined enzymatic pretreatment and high-pressure homogenization, and then subsequently incorporated into the PLA matrix to synthesize PLA/CNF biocomposite films via solution casting and melt compression. The prepared PLA/CNF biocomposite films were characterized in terms of transparency (UV-Vis spectroscopy), chemical structure (attenuated total reflectance-Fourier transform infrared, ATR-FTIR; X-ray powder diffraction, XRD), thermal (thermogravimetric analyzer, TGA; differential scanning calorimetry, DSC), and tensile properties. With 1.0–5.0 wt % additions of CNF to the PLA matrix, noticeable improvements in thermal and physical properties were observed for the resulting PLA/CNF biocomposites. The 2.5 wt % addition of CNF increased the tensile strength by 8.8%. The Tonset (initial degradation temperature) and Tmax (maximum degradation temperature) after adding 5.0 wt % CNF was increased by 20 °C, and 10 °C, respectively in the nitrogen atmosphere. These improvements were attributed to the good dispersibility and improved interfacial interaction of CNF in the PLA matrix.

scholarly journals Multi-layer assembly of cellulose nanofibrils in a microfluidic device for the selective capture and release of viable tumor cells from whole blood

Nanoscale ◽  
2020 ◽  
Vol 12 (42) ◽  
pp. 21788-21797
Author(s):  
Tharagan Kumar ◽  
Ruben R. G. Soares ◽  
Leyla Ali Dholey ◽  
Harisha Ramachandraiah ◽  
Negar Abbasi Aval ◽  
...  
Keyword(s):  
Tumor Cells ◽  
Microfluidic Device ◽  
Whole Blood ◽  
Cellulose Nanofibrils ◽  
Layer By Layer ◽  
Layer By Layer Assembly ◽  
Viable Tumor ◽  
Capture And Release ◽  
Layer Assembly

A microfluidic device modified with a layer-by-layer assembly of cellulose nanofibrils allows efficient capture and enzymatic release of tumor cells.

Modified Fenton Oxidation of Cellulose Fibers for Cellulose Nanofibrils Preparation

2018 ◽  
Vol 7 (1) ◽  
pp. 1129-1136 ◽  
Author(s):  
Qun Li ◽  
Aijiao Wang ◽  
Keying Long ◽  
Zhibin He ◽  
Ruitao Cha
Keyword(s):  
Cellulose Nanofibrils ◽  
Cellulose Fibers ◽  
Fenton Oxidation ◽  
Modified Fenton
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