scholarly journals Synthesis of Nanofibrillated Cellulose by Combined Ammonium Persulphate Treatment with Ultrasound and Mechanical Processing

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 640 ◽  
Author(s):  
Inese Filipova ◽  
Velta Fridrihsone ◽  
Ugis Cabulis ◽  
Agris Berzins
Keyword(s):  
Zeta Potential ◽  
Mechanical Treatment ◽  
Kraft Pulp ◽  
Cellulose Nanofibrils ◽  
Crystallinity Index ◽  
Nanofibrillated Cellulose ◽  
Ammonium Persulfate ◽  
Pulp Fibers ◽  
Persulfate Oxidation ◽  
Birch Kraft Pulp

Ammonium persulfate has been known as an agent for obtaining nanocellulose in recent years, however most research has focused on producing cellulose nanocrystals. A lack of research about combined ammonium persulfate oxidation and common mechanical treatment in order to obtain cellulose nanofibrils has been identified. The objective of this research was to obtain and investigate carboxylated cellulose nanofibrils produced by ammonium persulfate oxidation combined with ultrasonic and mechanical treatment. Light microscopy, atomic force microscopy (AFM), powder X-Ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and Zeta potential measurements were applied during this research. The carboxylated cellulose suspension of different fractions including nanofibrils, microfibrils and bundles were produced from bleached birch Kraft pulp fibers using chemical pretreatment with ammonium persulfate solution and further defibrillation using consequent mechanical treatment in a high shear laboratory mixer and ultrasonication. The characteristics of the obtained nanofibrils were: diameter 20–300 nm, crystallinity index 74.3%, Zeta potential −26.9 ± 1.8 mV, clear FTIR peak at 1740 cm−1 indicating the C=O stretching vibrations, and lower thermostability in comparison to the Kraft pulp was observed. The proposed method can be used to produce cellulose nanofibrils with defined crystallinity.

scholarly journals Alkali Extraction of Kraft Pulp Fibers: Influence on Fiber and Fluff Pulp Properties

2012 ◽  
Vol 7 (2) ◽  
pp. 155892501200700 ◽  
Author(s):  
Kristoffer Lund ◽  
Karin Sjöström ◽  
Harald Brelid
Keyword(s):  
Kraft Pulp ◽  
Pulp Fibers ◽  
Fiber Network ◽  
Alkali Extraction ◽  
Flexible Fiber ◽  
Softwood Pulp ◽  
Softwood Kraft Pulp ◽  
Patent Literature ◽  
Network Strength ◽  
Birch Kraft Pulp

The importance of hemicelluloses for the papermaking properties of pulp fibers is well documented. In the patent literature, it can be seen that there is also an interest in this type of modification of pulp fibers for use in absorption products. In this study, a Scandinavian softwood kraft pulp and a birch kraft pulp were alkali extracted at 3 different concentrations of NaOH (2%, 4% and 8% NaOH in the suspension). The alkali extraction removed a large part of the hemicelluloses from the pulp fibers and decreased the content of the charged groups. After extraction, the pulps were dried in the form of sheets (approx. 600 g/m2). The alkali extracted pulp fibers exhibited a greater decrease in swelling when re-wetted than untreated pulp. A significant increase in the curl index after extraction with 4% and 8% NaOH was also noted. The tensile strength index of the formed sheets increased at the lowest concentration of NaOH and, at the higher concentrations, a decrease was observed. The pulp sheets were dry defibrated at different defibration intensities and the performance of the resulting pulps in fluff pulp applications was studied. The air-laid fiber networks of softwood pulp fibers showed higher network strength than the networks of birch pulps. The birch pulp extracted at the highest alkali level tended to give the highest network strength. The results from the network strength tests also indicated that the increased curl of the fibers from the softwood pulp extracted at the highest alkali level rendered a more flexible fiber network. In water absorption tests, the alkali treated softwood fibers tended to give networks with a somewhat enhanced water holding capacity under pressure.

scholarly journals Effect of Mechanical Treatment of Eucalyptus Pulp on the Production of Nanocrystalline and Microcrystalline Cellulose

2021 ◽  
Vol 13 (11) ◽  
pp. 5888
Author(s):  
Walter Torezani Neto Boschetti ◽  
Ana Márcia Macedo Ladeira Carvalho ◽  
Angélica de Cássia Oliveira Carneiro ◽  
Graziela Baptista Vidaurre ◽  
Fernando José Borges Gomes ◽  
...  
Keyword(s):  
Acid Hydrolysis ◽  
Microcrystalline Cellulose ◽  
Kraft Pulp ◽  
Crystallinity Index ◽  
Pulp Fibers ◽  
Cellulose I ◽  
Physical Treatment ◽  
Eucalyptus Pulp ◽  
Mechanical Pretreatment ◽  
Eucalyptus Kraft Pulp

This study aimed to assess the effect of mechanical pretreatment on bleached eucalyptus kraft pulp fibers and investigate the influence of reaction time and temperature on the properties and yield of nanocrystalline cellulose (NCC) and microcrystalline cellulose (MCC). Two types of pulps were hydrolyzed, pulp 1 (control, whole fibers) and pulp 2 (mechanically pretreated, disintegrated fibers). NCC and MCC particles were obtained by sulfuric acid hydrolysis (60% w/w) of eucalyptus pulps under different conditions of time (30–120 min) and temperature (45–55 °C). Physical treatment of kraft pulp facilitated acid hydrolysis, resulting in higher NCC yields compared with no pretreatment. The morphologic properties and crystallinity index (CI) of NCC and MCC were little affected by pulp pretreatment. NCC particles obtained from pulps 1 and 2 were needle-shaped, with mean diameters of 6 and 4 nm, mean lengths of 154 and 130 nm, and CI of 74.6 and 76.8%, respectively. MCC particles obtained from pulps 1 and 2 were rod-shaped, with mean diameters of 2.4 and 1.4 µm, mean lengths of 37 and 22 µm, and CI of 73.1 and 74.5%, respectively. Pulps 1 and 2 and their respective NCC and MCC derivatives had a cellulose I crystalline structure.

scholarly journals The Properties of OPEFB Cellulose Nanofibrils Produced by A Different Mode of Ultrafine Grinding

2021 ◽  
Vol 891 (1) ◽  
pp. 012016
Author(s):  
P Amanda ◽  
S Nabila ◽  
N Qonita ◽  
R S Ningrum ◽  
Ismadi ◽  
...  
Keyword(s):  
Kraft Pulp ◽  
Cellulose Nanofibrils ◽  
Crystallinity Index ◽  
Morphological Properties ◽  
Mechanical Grinding ◽  
Bleached Pulp ◽  
Ultrafine Grinding ◽  
The Hierarchical Structure ◽  
Size Uniformity ◽  
Mechanical Fibrillation

Abstract Cellulose Nanofibrils (CNFs) was resulted from deconstruction of the hierarchical structure of cellulose. CNFs are commonly obtained by mechanical fibrillation, such as ultrafine grinding processes and its variation. Nevertheless, the influence of different treatments on the properties of the resulting CNF especially from variety of ultrafine grinding mode has not been reported. This study investigates the properties of cellulose nanofibrils (CNF) produced from bleached pulp oil palm empty fruit bunch (OPEFB) Kraft pulp through an ultrafine grinder with two different treatments in the fibrillation process. These two treatments were: 1) ultrafine grinder with increasing gaps distances; -30, -50, -70, and -90 µm with five cycles in every gap, 2) ultrafine grinder on constant gaps (-30µm) with increasing grinding cycles: 5, 10, 15, 30, and 40 cycles through the grinder. The influence of the treatment was evaluated through particle size distribution, crystallinity index, and morphological properties. The result showed that the increasing gaps treatment efficiently improved the size uniformity of CNFs, length 147-139.5 nm, and scanning electron microscope micrograph confirmed that the diameter of CNF was smaller with the increasing grinding gaps than increasing grinding cycles. However, the increasing cycle’s treatment produced CNF with a higher crystallinity index. The crystallinity index (CrI) of the CNF decreased from 71.27 to 62.25% with increasing gaps, whereas the CrI of the CNF from increasing cycles was 69.35%. This study provides a valuable guideline for determining the appropriate process to produce CNF especially by mechanical grinding using ultrafine grinder from OPEFB according to the desired result.

scholarly journals NANOCELLULOSE OBTAINED MECHANICALLY BY DIFFERENT COLLOID GRINDING INTENSITIES

FLORESTA ◽  
2019 ◽  
Vol 50 (1) ◽  
pp. 897
Author(s):  
Marina Stygar Lopes ◽  
Daniele Cristina Potulski ◽  
Lívia Cássia Viana ◽  
Mayara Elita Carneiro ◽  
Graciela Inês Bolzon de Muniz ◽  
...  
Keyword(s):  
Mechanical Treatment ◽  
Average Particle Size ◽  
Microscopic Analysis ◽  
Crystallinity Index ◽  
Average Diameter ◽  
Nanofibrillated Cellulose ◽  
Average Particle ◽  
Mechanical Grinding ◽  
Mechanical Process ◽  
Transmission Electron

Recent advances in nanocellulose technology have enabled production of materials for various applications with attractive properties. The aim of this work was to analyze the nanofibrillated cellulose of Eucalyptus sp. obtained by different grinding intensities. Delignified Eucalyptus sp. kraftpulp was used to obtain the nanofibrillated cellulose in the mechanical grinding process, with 2, 10 and 20 passes. Images were captured by scanning and transmission electron microscopy to observe cellulose structures. For each mechanical treatment, three films were produced, which were used to evaluate the crystallinity index. Viscosity measurement evaluated the influence of mechanical treatment on nanofibrillated cellulose. Microscopic analysis showed that the mechanical process promoted fiber defibrillation, resulting in the exposure of microfibrils in all treatments evaluated. Differences were not verified in the conformation and dimensions of the structures for the different numbers of passes, and the nanofibrils presented average diameter of approximately 30 nm. The mechanical process to obtain the nanofibrillated cellulose reduced of the crystallinity index and the viscosity of the nanofibrillated cellulose compared to cellulose before processing. The average particle size declined with rising number of grinder passes.

Tailorable cellulose II nanocrystals (CNC II) prepared in mildly acidic lithium bromide trihydrate (MALBTH)

2021 ◽  
Vol 23 (7) ◽  
pp. 2778-2791
Author(s):  
Ning Li ◽  
Huiyang Bian ◽  
J. Y. Zhu ◽  
Peter N. Ciesielski ◽  
Xuejun Pan
Keyword(s):  
Kraft Pulp ◽  
Lithium Bromide ◽  
Ammonium Persulfate ◽  
Cellulose Ii ◽  
Persulfate Oxidation ◽  
Bleached Kraft Pulp ◽  
Hydrolysis Of ◽  
Polymorph Transformation

Cellulose II nanocrystals were prepared from bleached kraft pulp via simultaneous hydrolysis of disordered cellulose and polymorph transformation in mildly acidic lithium bromide trihydrate followed by ammonium persulfate oxidation.

An effective method for determining the retention and distribution of cellulose nanofibrils in paper handsheets by dye labeling

TAPPI Journal ◽  
2018 ◽  
Vol 17 (03) ◽  
pp. 157-164 ◽  
Author(s):  
Shengdan Wang ◽  
Wenhua Gao ◽  
Kefu Chen ◽  
Jinsong Zeng ◽  
Jun Xu ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Congo Red ◽  
Kraft Pulp ◽  
Cellulose Nanofibrils ◽  
Standard Curve ◽  
Congo Red Dye ◽  
Mechanical Disintegration ◽  
Softwood Kraft Pulp ◽  
White Water ◽  
Red Dye

Cellulose nanofibrils (CNF) were prepared by cellulase in conjunction with mechanical disintegration from the bleached softwood kraft pulp and labelled by Congo red dye. The labelled CNF were used to investigate the retention and distribution of CNF in paper handsheets. The retention of the labelled CNF was obtained by measuring the absorbance of white water using an ultraviolet-visible spectrophotometer. The results showed that this method for measuring the retention was rapid, feasible, and sensitive, owing to the high correlation coefficient R2 (0.9993) of the standard curve. The labelled CNF showed even distribution in paper handsheets. The colorimetric values of paper handsheets were explored with a residual ink analyzer.

Desorption of Cationic Polyacrylamide from Bleached Kraft Pulp Fibers

1987 ◽  
Vol 19 (5-6) ◽  
pp. 939-951 ◽  
Author(s):  
Clifton F. Warren ◽  
R. Gehr
Keyword(s):  
Adsorption Isotherm ◽  
Total Nitrogen ◽  
Kraft Pulp ◽  
Detection System ◽  
Cationic Polyelectrolyte ◽  
Chemiluminescence Detection ◽  
Pulp Fibers ◽  
Paper Manufacturing ◽  
Bleached Kraft Pulp ◽  
Receiving Water

The adsorption and desorption behaviour of a cationic polyelectrolyte contacted with wood pulp fibers was determined by total nitrogen analysis using a pyrolysis/chemiluminescence detection system. Dialysed polymer generated an adsorption isotherm of higher affinity than did non-dialysed polymer. Capacity adsorption was maximized at pH 7, but decreased in the presence of alum depending on the dosage. Desorption of non-dialysed polymer was caused by changes in pH above or below 7.0 as well as by addition of alum. However for the alum doses typically encountered in paper manufacturing, significant desorption is unlikely. Nevertheless, the contaminants in non-dialysed polymers do hinder adsorption, and effluents from those processes using both alum and polymer may contain quantities of unadsorbed or desorbed polyelectrolytes which could be damaging to receiving water bodies.

scholarly journals Cellulose Nanofibril (CNF) Films and Xylan from Hot Water Extracted Birch Kraft Pulps

2019 ◽  
Vol 9 (16) ◽  
pp. 3436 ◽  
Author(s):  
Marc Borrega ◽  
Hannes Orelma
Keyword(s):  
Food Packaging ◽  
Kraft Pulp ◽  
Barrier Properties ◽  
Hot Water ◽  
Kraft Pulps ◽  
Cellulose Nanofibril ◽  
Vapour Permeability ◽  
Transparent Films ◽  
Cnf Films ◽  
Birch Kraft Pulp

The effects of xylan extraction from birch kraft pulp on the manufacture and properties of cellulose nanofibril (CNF) films were here investigated. Hot water extractions of bleached and unbleached kraft pulps were performed in a flow-through system to remove and recover the xylan. After the extraction, the pulps were oxidized with 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) and fibrillated in a high-pressure microfluidizer. Compared to CNF from bleached kraft pulp, the CNF dispersions obtained from water-extracted pulps were less viscous and generally contained a higher amount of microfiber fragments, although smaller in size. In all cases, however, smooth and highly transparent films were produced from the CNF dispersions after the addition of sorbitol as plasticizer. The CNF films made from water-extracted pulps showed a lower tensile strength and ductility, probably due to their lower xylan content, but the stiffness was only reduced by the presence of lignin. Interestingly, the CNF films from water-extracted bleached pulps were less hydrophilic, and their water vapour permeability was reduced up to 25%. Therefore, hot water extraction of bleached birch kraft pulp could be used to produce CNF films with improved barrier properties for food packaging, while obtaining a high-purity xylan stream for other high-value applications.

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