scholarly journals Revisiting the Dissolution of Cellulose in NaOH as “Seen” by X-rays

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 342 ◽  
Author(s):  
Birte Martin-Bertelsen ◽  
Erika Andersson ◽  
Tobias Köhnke ◽  
Artur Hedlund ◽  
Lars Stigsson ◽  
...  
Keyword(s):  
Microcrystalline Cellulose ◽  
Scattering Data ◽  
Regenerated Cellulose ◽  
X Rays ◽  
Cotton Production ◽  
Textile Fibers ◽  
Solvent Quality ◽  
Nmr Data ◽  
Dissolution Properties ◽  
Weak Attraction

Cotton production is reaching a global limit, leading to a growing demand for bio-based textile fibers produced by other means. Textile fibers based on regenerated cellulose from wood holds great potential, but in order to produce fibers, the components need to be dissolved in suitable solvents. Furthermore, the dissolution process of cellulose is not yet fully understood. In this study, we investigated the dissolution state of microcrystalline cellulose in aqueous NaOH by using primarily scattering methods. Contrary to previous findings, this study indicated that cellulose concentrations of up to 2 wt % are completely molecularly dissolved in 8 wt % NaOH. Scattering data furthermore revealed the presence of semi-flexible cylinders with stiff segments. In order to improve the dissolution capability of NaOH, the effects of different additives have been of interest. In this study, scattering data indicated that the addition of ZnO decreased the formation of aggregates, while the addition of PEG did not improve the dissolution properties significantly, although preliminary NMR data did suggest a weak attraction between PEG and cellulose. Overall, this study sheds further light on the dissolution of cellulose in NaOH and highlights the use of scattering methods to assess solvent quality.

scholarly journals Preparation of Microcrystalline Cellulose from Water Hyacinth Reinforced Polylactic Acid Biocomposite

2018 ◽  
Vol 187 ◽  
pp. 02003
Author(s):  
Teerapa Semachai ◽  
Panitnad Chandranupap ◽  
Pravitra Chandranupap
Keyword(s):  
Polylactic Acid ◽  
Microcrystalline Cellulose ◽  
Water Hyacinth ◽  
Morphological Analysis ◽  
X Rays ◽  
Elongation At Break ◽  
Internal Mixing ◽  
Ft Ir ◽  
Treated Fiber ◽  
Ft Ir Spectroscopy

In this work, we successfully mixed polylactic acid (PLA) with microcrystalline cellulose (MCC) from water hyacinth. The MCC was prepared by treating water hyacinth fiber (WHF). Then hydrochloric acid was used to hydrolyze treated fiber to MCC. X-rays diffraction (XRD) showed that the MCC produced has 73.28 per cent crystallinity. Internal mixing was used to combine composites between MCC and PLA. Percentages of MCC were 1, 5, 10 and 15, respectively. Fourier transform infrared (FT-IR) spectroscopy indicated that the interaction between MCC and PLA are only mechanically interaction. Tensile testing of this composite (ASTM D638) revealed that tensile strength and percentage of elongation at break decreased but the increase of young's modulus. The morphological analysis was observed thru composites fractured surface by Scanning Electron Microscope (SEM). They showed a void between cellulosic fiber and PLA when high amount of MCC conformed with tensile results.

scholarly journals The Role of Montmorillonite Loading on the Physicochemical Properties of Regenerated Cellulose Nanocomposite Films Obtained from Microcrystalline Cellulose

2020 ◽  
Vol 31 (1) ◽  
pp. 85-103
Author(s):  
P. R. D. Weerasooriya ◽  
◽  
S. N. Ain Jamal ◽  
M. K. Mohamad Haafiz ◽  
H. P. S. Abdul Khalil ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Microcrystalline Cellulose ◽  
Nanocomposite Films ◽  
Regenerated Cellulose

X-Ray Determination of Site Occupation Parameters in Ordered Ternaries Cu(Aux.M1x.)M = Ni,Pd

1990 ◽  
Vol 213 ◽  
Author(s):  
R. Kumar ◽  
C. J. Sparks ◽  
T. Shiraishi ◽  
E.D. Specht ◽  
P. Zschack ◽  
...  
Keyword(s):  
Rietveld Method ◽  
Scattering Data ◽  
X Rays ◽  
X Ray ◽  
Site Occupation ◽  
Intensity Measurements ◽  
X Ray Scattering ◽  
Chemical Phase ◽  
Multiple Wavelengths ◽  
Scattering Factor

ABSTRACTX-ray scattering data obtained for multiple wavelengths with synchrotron radiation were analyzed by the Rietveld method to determine Ni and Pd distributions on the Cu(000) and Au(½½½) sites in the CuAuI tetragonal P4/mmm structure. Alloys of CuAuxM1-x containing 6 at. % Ni or 10 and 25 at. % Pd were processed to obtain maximum ordering. Nickel is predominantly found on the Cu site and most all the Pd is found on the Au site. The uncertainty in site occupation parameters is discussed for various contributions which affect powder intensity measurements. For highly absorbing materials, an observed powder roughness effect decreases the low angle (2θ) intensities relative to the high 2θ intensities. This effect reduces the reliability of the thermal parameters and obscures a proper description of the thermal motion of the two sublattices. Corrections to the X-ray intensity data for surface roughness/porosity effects reduce uncertainties to about ±1 at. % on the refined value of the site occupations. This use of variable wavelength X-rays with simultaneous refinement of the corresponding data is capable of distinguishing site occupations even between two elements of almost equal scattering factor as, for example, Cu and Ni atoms in this investigation. Chemical phase stability is related to the site occupation parameters.

Rheology and microstructure of concentrated microcrystalline cellulose (MCC)/1-allyl-3-methylimidazolium chloride (AmimCl)/water mixtures

Soft Matter ◽  
2018 ◽  
Vol 14 (37) ◽  
pp. 7615-7624 ◽  
Author(s):  
Ashna Rajeev ◽  
Abhijit P. Deshpande ◽  
Madivala G. Basavaraj
Keyword(s):  
Microcrystalline Cellulose ◽  
Flow Properties ◽  
Solvent Quality

Water added to a solution of microcrystalline cellulose (MCC) in 1-allyl-3-methylimidazolium chloride (AmimCl) reduces the solvent quality and causes significant changes in the flow properties and microstructure due to restructuring and aggregation of cellulose molecules.

scholarly journals A Coil-to-Helix Transition Serves as a Binding Motif for hSNF5 and BAF155 Interaction

2020 ◽  
Vol 21 (7) ◽  
pp. 2452 ◽  
Author(s):  
Jeongmin Han ◽  
Iktae Kim ◽  
Jae-Hyun Park ◽  
Ji-Hye Yun ◽  
Keehyoung Joo ◽  
...  
Keyword(s):  
Transcriptional Control ◽  
Scattering Data ◽  
Binding Motif ◽  
X Ray Crystallography ◽  
Loop Region ◽  
Binding Interface ◽  
Nmr Data ◽  
Terminal Loop ◽  
Chromatin Remodeling Complexes ◽  
Rhabdoid Tumors

Human SNF5 and BAF155 constitute the core subunit of multi-protein SWI/SNF chromatin-remodeling complexes that are required for ATP-dependent nucleosome mobility and transcriptional control. Human SNF5 (hSNF5) utilizes its repeat 1 (RPT1) domain to associate with the SWIRM domain of BAF155. Here, we employed X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and various biophysical methods in order to investigate the detailed binding mechanism between hSNF5 and BAF155. Multi-angle light scattering data clearly indicate that hSNF5171–258 and BAF155SWIRM are both monomeric in solution and they form a heterodimer. NMR data and crystal structure of the hSNF5171–258/BAF155SWIRM complex further reveal a unique binding interface, which involves a coil-to-helix transition upon protein binding. The newly formed αN helix of hSNF5171–258 interacts with the β2–α1 loop of hSNF5 via hydrogen bonds and it also displays a hydrophobic interaction with BAF155SWIRM. Therefore, the N-terminal region of hSNF5171–258 plays an important role in tumorigenesis and our data will provide a structural clue for the pathogenesis of Rhabdoid tumors and malignant melanomas that originate from mutations in the N-terminal loop region of hSNF5.

scholarly journals Dissolution of cellulose using a combination of hydroxide bases in aqueous solution

Cellulose ◽  
2019 ◽  
Vol 27 (1) ◽  
pp. 101-112 ◽  
Author(s):  
Beatrice Swensson ◽  
Anette Larsson ◽  
Merima Hasani
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Microcrystalline Cellulose ◽  
Low Temperatures ◽  
Dynamic Rheology ◽  
Organic Base ◽  
Single Base ◽  
Solvent Quality ◽  
Solvent Stability

Abstract In order to further understand the role of the cation when dissolving cellulose in aqueous solutions of hydroxide bases, different bases were combined in solution. Up to 5 wt.% of microcrystalline cellulose was dissolved using a combination of NaOH and the organic base tetramethylammonium hydroxide (TMAH) in water at low temperatures. Thermoscans of solutions containing both NaOH(aq) and TMAH(aq) indicated that cellulose interaction with TMAH seems to be favoured over NaOH. Dynamic rheology measurements of the solutions revealed that combining the two bases delayed gelation significantly when compared to cellulose dissolved in NaOH(aq) or TMAH(aq) alone. Intrinsic viscosity of cellulose in the combined NaOH- and TMAH(aq) solutions was slightly higher than that of the single-base solutions, indicating a slight increase in solvent quality. This shows that combining bases may lead to synergies that improve solvent stability without requiring the use of other additives. Graphic abstract

Three-dimensional reconstruction of liquid phases in disordered mesopores usingin situsmall-angle scattering

2013 ◽  
Vol 46 (2) ◽  
pp. 493-504 ◽  
Author(s):  
Cedric J. Gommes
Keyword(s):  
Mesoporous Materials ◽  
Small Angle ◽  
Solid Phase ◽  
Gaussian Random Field ◽  
Three Dimensional ◽  
Small Angle Scattering ◽  
Scattering Data ◽  
Wetting Transition ◽  
X Rays ◽  
Angle Scattering

Small-angle scattering of X-rays (SAXS) or neutrons is one of the few experimental methods currently available for thein situanalysis of phenomena in mesoporous materials at the mesoscopic scale. In the case of disordered mesoporous materials, however, the main difficulty of the method lies in the data analysis. A stochastic model is presented, which enables one to reconstruct the three-dimensional nanostructure of liquids confined in disordered mesopores starting from small-angle scattering data. This so-called plurigaussian model is a multi-phase generalization of clipped Gaussian random field models. Its potential is illustrated through the synchrotron SAXS analysis of a gel permeated with a critical nitrobenzene/hexane solution that is progressively cooled below its consolute temperature. The reconstruction brings to light a wetting transition whereby the nanostructure of the pore-filling liquids passes from wetting layers that uniformly cover the solid phase of the gel to plugs that locally occlude the pores. Using the plurigaussian model, the dewetting phenomenon is analyzed quantitatively at the nanometre scale in terms of changing specific interface areas, contact angle and specific length of the triple line.

Specular and Off-Specular X-Ray Scattering as Quantitative Structural Probes of Multilayers. Application to MN/IR(111) Superlattices

1995 ◽  
Vol 382 ◽  
Author(s):  
H.M. Fischer ◽  
H.E. Fischer ◽  
M. Bessiere ◽  
J.-F. Bobo ◽  
O. Lenoble ◽  
...  
Keyword(s):  
Deposition Temperature ◽  
Surface Defects ◽  
Single Layer ◽  
Scattering Data ◽  
Length Scale ◽  
X Rays ◽  
Interfacial Roughness ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

ABSTRACTDiffuse scattering of X rays is a particularly useful tool for studying interface and surface defects in single layer films. We have extended this technique to the study of multilayers. The samples are Mn/Ir(111) superlattices where Mn is pseudomorphic to Ir. We have studied three typical samples prepared at different substrate temperatures. Using theoretical analyses and simulations of both specular and off-specular X-ray scattering data at small angles as well as large angles, we show that large length-scale interfacial roughness is mainly due to the formation of terraces during growth at low deposition temperature, whereas small length-scale interfacial roughness occurs preferably at high deposition temperature and is mainly due to an atomic interdiffusion (i.e. the formation of an interface alloy) which manages to maintain a high degree of crystallographic order.

scholarly journals The power of SANS, combined with deuteration and contrast variation, for structural studies of functional and dynamic biomacromolecular systems in solution

2020 ◽  
Vol 236 ◽  
pp. 03002
Author(s):  
Emilie Mahieu ◽  
Ziad Ibrahim ◽  
Martine Moulin ◽  
Michael Härtlein ◽  
Bruno Franzetti ◽  
...  
Keyword(s):  
Small Angle ◽  
Structural Information ◽  
Protein Complexes ◽  
Scattering Data ◽  
X Rays ◽  
Contrast Variation ◽  
Functional Protein ◽  
X Ray Scattering ◽  
Specific Proteins ◽  
Scattering Signal

Small-angle neutron scattering (SANS), combined with macromolecular deuteration and solvent contrast variation (H2O/D2O exchange) allows focussing selectively on the signal of specific proteins in multi-protein complexes or mixtures of isolated proteins. We illustrate this unique capacity by the example of a functional protein-degradation system in solution, the PAN-20S proteasome complex in the presence of a protein substrate, ssrA-tagged GFP. By comparing experimental SANS data with synthetic SAXS (small-angle X-ray scattering) data, predicted for the same system under identical conditions, we show that SANS, when combined with macromolecular deuteration and solvent contrast variation, can specifically focus on the conformation of the PAN unfoldase, even in the presence of very large GFP aggregates. Likewise, structural information of native GFP states can be visualized in detail, even in the presence of the much larger PAN-20S unfoldase-protease oligomers, which would dominate the overall scattering signal when using X-rays instead of neutrons.

Explicit formula for the solution of the phaseless inverse scattering problem of imaging of nano structures

2015 ◽  
Vol 23 (2) ◽  
Author(s):  
Michael V. Klibanov ◽  
Vladimir G. Romanov
Keyword(s):  
Born Approximation ◽  
Scattering Problem ◽  
Inverse Scattering Problem ◽  
Scattered Wave ◽  
Scattering Data ◽  
Unknown Coefficient ◽  
X Rays ◽  
Reconstruction Formula ◽  
Nano Structures ◽  
Complex Valued

AbstractImaging of nano structures is necessary for the quality control in their manufacturing. In the case when X-rays probe the medium, only the modulus of the complex valued scattered wave field can be measured. The phase cannot be measured. In the case of the Born approximation, we obtain an explicit reconstruction formula for the unknown coefficient from the phaseless scattering data.

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