scholarly journals Effect of the Dissolving Method on the Dissolution of Dissolving Pulp Cellulose Fibers with Different Dried-States in Different NaOH/Additives Aqueous Solutions

Author(s):  
Weiwei Kong ◽  
Guangrong Yu ◽  
Jiong Xing ◽  
Hongjie Zhang ◽  
Meihua Liu ◽  
...  
2021 ◽  
Author(s):  
Weiwei Kong ◽  
Guangrong Yu ◽  
Jiong xing ◽  
Rui Kong ◽  
Meihua Liu ◽  
...  

Abstract A NaOH/urea (or thiourea) solvent system capable of dissolving cellulose at lower temperatures is a breakthrough in cellulose chemistry, and it was reported that cellulose rapidly dissolved when it was added to a precooled aqueous solution of sodium hydroxide (NaOH) and additives. Therefore, this work compared the effectiveness of the direct dissolution method and freezing-thaw method in dissolving pulp fiber and pure cellulose. Three aqueous solutions were examined: 7% NaOH/12% urea, 9.5% NaOH/4.5% thiourea, and 8% NaOH/8% urea/6.5% thiourea. The dissolving capacity of three NaOH/additives aqueous solutions was analyzed by polarized optical microscopy and the dissolved cellulose proportion was determined. The results showed that the never-dried softwood dissolving pulp and bamboo dissolving pulp achieved better dissolution using freezing-thaw method than using direct dissolution method in the three aqueous solutions. The dissolving method had a negligible effect on the dissolution of each dissolving pulp in the 8% NaOH/8% urea/6.5% thiourea solution. It seems that the direct dissolution method was more suitable for oven-dried microcrystalline cellulose with a low degree of polymerization (DP) and the freezing-thaw method was more suitable for never-dried pulp cellulose fibers with a higher DP.


Polymer ◽  
2006 ◽  
Vol 47 (8) ◽  
pp. 2839-2848 ◽  
Author(s):  
Xuming Chen ◽  
Christian Burger ◽  
Dufei Fang ◽  
Dong Ruan ◽  
Lina Zhang ◽  
...  

2007 ◽  
Vol 8 (6) ◽  
pp. 1918-1926 ◽  
Author(s):  
Xuming Chen ◽  
Christian Burger ◽  
Fen Wan ◽  
Jun Zhang ◽  
Lixia Rong ◽  
...  

2017 ◽  
Vol 88 (21) ◽  
pp. 2485-2492 ◽  
Author(s):  
Stina Björquist ◽  
Julia Aronsson ◽  
Gunnar Henriksson ◽  
Anders Persson

Cotton is not the answer to meet the rapidly growing demand for textile fibers. Wood-based regenerated cellulose fibers are an attractive alternative. Since wood is a candidate to replace fossil raw materials in so many applications of the circular economy, other sources need investigation. Cotton linters work in the viscose process – can cotton waste be used to make dissolving pulp? We describe the textile qualities of lyocell fibers from (i) pure cotton waste pulp and (ii) blending with conventional dissolving pulp. The staple fibers were tensile tested, yarns spun and tensile tested and knitted, and tested for shrinkage, water and dye sorption, abrasion resistance, fuzzing and pilling, staining and fastness. TENCEL® staple fibers and off-the-shelf TENCEL® yarn were used as references. The results show that the two study fibers had tenacity and an E-modulus that exceeded the staple fiber reference. Also, the study yarns were at least as good as the spun reference yarn and the commercial off-the-shelf yarn in terms of wet tenacity. Single jerseys made from the study yarns shrunk less upon laundering, which is surprising since they could absorb at least as much water at a comparable rate as the references. Dyeability, staining and color fastness, durability and pilling tendency showed that the two study fiber tricots performed at least as good as the references. This study suggests that cotton waste is a promising candidate for special grade pulp to suit niche regenerated fiber products or to spice up conventional wood-based dissolving pulp.


Author(s):  
K. J. Böhm ◽  
a. E. Unger

During the last years it was shown that also by means of cryo-ultra-microtomy a good preservation of substructural details of biological material was possible. However the specimen generally was prefixed in these cases with aldehydes.Preparing ultrathin frozen sections of chemically non-prefixed material commonly was linked up to considerable technical and manual expense and the results were not always satisfying. Furthermore, it seems to be impossible to carry out cytochemical investigations by means of treating sections of unfixed biological material with aqueous solutions.We therefore tried to overcome these difficulties by preparing yeast cells (S. cerevisiae) in the following manner:


Author(s):  
S.A.C. Gould ◽  
B. Drake ◽  
C.B. Prater ◽  
A.L. Weisenhorn ◽  
S.M. Lindsay ◽  
...  

The atomic force microscope (AFM) is an instrument that can be used to image many samples of interest in biology and medicine. Images of polymerized amino acids, polyalanine and polyphenylalanine demonstrate the potential of the AFM for revealing the structure of molecules. Images of the protein fibrinogen which agree with TEM images demonstrate that the AFM can provide topographical data on larger molecules. Finally, images of DNA suggest the AFM may soon provide an easier and faster technique for DNA sequencing.The AFM consists of a microfabricated SiO2 triangular shaped cantilever with a diamond tip affixed at the elbow to act as a probe. The sample is mounted on a electronically driven piezoelectric crystal. It is then placed in contact with the tip and scanned. The topography of the surface causes minute deflections in the 100 μm long cantilever which are detected using an optical lever.


Author(s):  
S. E. Keckler ◽  
D. M. Dabbs ◽  
N. Yao ◽  
I. A. Aksay

Cellular organic structures such as wood can be used as scaffolds for the synthesis of complex structures of organic/ceramic nanocomposites. The wood cell is a fiber-reinforced resin composite of cellulose fibers in a lignin matrix. A single cell wall, containing several layers of different fiber orientations and lignin content, is separated from its neighboring wall by the middle lamella, a lignin-rich region. In order to achieve total mineralization, deposition on and in the cell wall must be achieved. Geological fossilization of wood occurs as permineralization (filling the void spaces with mineral) and petrifaction (mineralizing the cell wall as the organic component decays) through infiltration of wood with inorganics after growth. Conversely, living plants can incorporate inorganics into their cells and in some cases into the cell walls during growth. In a recent study, we mimicked geological fossilization by infiltrating inorganic precursors into wood cells in order to enhance the properties of wood. In the current work, we use electron microscopy to examine the structure of silica formed in the cell walls after infiltration of tetraethoxysilane (TEOS).


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