scholarly journals X-Ray Investigations on Cellulose II and Mixtures of Cellulose I and II. I. A Method for Characterizing and Determining the Relative Contents of the two Modifications.

1960 ◽  
Vol 14 ◽  
pp. 683-688 ◽  
Author(s):  
Jon Gjønnes ◽  
Nico Norman ◽  
J. Åselius ◽  
Susanne Refn ◽  
Gertrud Westin
Keyword(s):  
Cellulose Ii ◽  
Cellulose I ◽  
X Ray

scholarly journals Stable, metastable and unstable cellulose solutions

2017 ◽  
Vol 4 (8) ◽  
pp. 170487 ◽  
Author(s):  
Marta Gubitosi ◽  
Pegah Nosrati ◽  
Mona Koder Hamid ◽  
Stefan Kuczera ◽  
Manja A. Behrens ◽  
...  
Keyword(s):  
Microcrystalline Cellulose ◽  
Small Angle ◽  
Supersaturated Solution ◽  
Cellulose Ii ◽  
Cellulose I ◽  
Tetrabutylammonium Hydroxide ◽  
X Ray ◽  
Stable Regime ◽  
X Ray Scattering ◽  
A Minor

We have characterized the dissolution state of microcrystalline cellulose (MCC) in aqueous tetrabutylammonium hydroxide, TBAH(aq), at different concentrations of TBAH, by means of turbidity and small-angle X-ray scattering. The solubility of cellulose increases with increasing TBAH concentration, which is consistent with solubilization driven by neutralization. When comparing the two polymorphs, the solubility of cellulose I is higher than that of cellulose II. This has the consequence that the dissolution of MCC (cellulose I) may create a supersaturated solution with respect to cellulose II. As for the dissolution state of cellulose, we identify three different regimes. (i) In the stable regime, corresponding to concentrations below the solubility of cellulose II, cellulose is molecularly dissolved and the solutions are thermodynamically stable. (ii) In the metastable regime, corresponding to lower supersaturations with respect to cellulose II, a minor aggregation of cellulose occurs and the solutions are kinetically stable. (iii) In the unstable regime, corresponding to larger supersaturations, there is macroscopic precipitation of cellulose II from solution. Finally, we also discuss strong alkali solvents in general and compare TBAH(aq) with the classical NaOH(aq) solvent.

Eco-Friendly Preparation of Nanofibrillated Cellulose from Water Hyacinth Using NaOH/Urea Pretreatment

2020 ◽  
Vol 990 ◽  
pp. 225-230
Author(s):  
Kraiwit Pakutsah ◽  
Duangdao Aht-Ong
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Water Hyacinth ◽  
Aqueous Suspension ◽  
Nanofibrillated Cellulose ◽  
Cellulose Ii ◽  
Cellulose I ◽  
X Ray ◽  
Transmission Electron ◽  
Water Hyacinth Fiber

In this work, we described an effective approach to prepare nanofibrillated cellulose (NFC) with cellulose II structure under mild condition. Firstly, the water hyacinth (WH) was subjected to a series of a two-step chemical treatment, NaOH/urea pretreatment, and mechanical defibrillation at different defibrillation times. After that, raw water hyacinth fiber (RWF), bleached water hyacinth fiber (BWF), NaOH/urea pretreated water hyacinth fiber (PWF), and the resulting NFC were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD) as well as rheological measurements. It was found that RWF and BWF exhibited cellulose I crystal structure, whereas PWF and the obtained NFC possessed cellulose II crystal structure. FTIR analysis confirmed the evidence that no other chemical reactions preferentially occurred during both NaOH/urea pretreatment and mechanical defibrillation. As evidenced by rheological properties analysis, the NFC aqueous suspension with a gel-like structure demonstrated a shear-thinning behavior. The obtained NFC could potentially be utilized as a reinforcement for polymeric composites.

scholarly journals CELLULOSE NANOCRYSTALS FROM UNDERUTILIZED POLYTHIA LONGIFOLIA SEED

2017 ◽  
Vol 14 (27) ◽  
pp. 10-18
Author(s):  
Adewale ADEWUYI ◽  
Fabiano Vargas PEREIRA
Keyword(s):  
Adsorption Capacity ◽  
Cellulose Nanocrystals ◽  
Cellulose Ii ◽  
X Ray Diffraction ◽  
Cellulose I ◽  
Sem Images ◽  
X Ray ◽  
Potential Source ◽  
Swelling Capacity ◽  
Water Holding

Polythia longifolia seed (PL), an underutilized seed in Nigeria was used as a starting material to prepare Polythia longifolia cellulose nanocrystals (PLN). Polythia longifolia cellulose (PLC) was first isolated and subjected to sulfuric acid hydrolysis followed by ultrasonication and homogenization. PL, PLC and PLN were characterized using Fourier transformed infrared (FTIR), x-ray diffraction (XRD), thermogravimetric analysis (TG) and scanning electron microscopy (SEM). PLC and PLN were evaluated for their heavy metal adsorption capacity, swelling capacity, water holding capacity and oil holding capacity. SEM images reveal elliptical granules of PLN while XRD shows a mixture of polymorphs of cellulose I and cellulose II. PLN displayed a better water holding, oil holding and swelling capacities. PLN also exhibited a higher adsorption capacity towards Cu2+ and Pb2+ ions than PLC. The results showed that Polythia longifolia seed can serve as a potential source of cellulose nanocrystals which might be useful in other applications.

scholarly journals X-Ray Investigations on Cellulose II and Mixtures of Cellulose I and II. 2. Lateral Order in Cellulose II.

1960 ◽  
Vol 14 ◽  
pp. 689-691 ◽  
Author(s):  
Jon Gjønnes ◽  
Nico Norman ◽  
J. Åselius ◽  
Susanne Refn ◽  
Gertrud Westin
Keyword(s):  
Cellulose Ii ◽  
Cellulose I ◽  
X Ray

Cell-wall studies in the Chlorophyceae. I. A general survey of submicroscopic structure in filamentous species

1952 ◽  
Vol 140 (899) ◽  
pp. 244-274 ◽  
Keyword(s):  
Fibrillar Structure ◽  
Cellulose Ii ◽  
Cellulose I ◽  
General Survey ◽  
Random Orientation ◽  
Submicroscopic Structure ◽  
X Ray ◽  
Filamentous Green Algae ◽  
Large Bulk ◽  
The Status

The paper constitutes a survey of the fine structure of the walls in about sixty species of filamentous green algae, as revealed chiefly by the methods of X -ray analysis. With some species use has also been made of the polarizing microscope and of staining reactions. I t is known that wall constituents in the algae are very variable, and one aim of the investigation has been to systematize this variation. The chief aim has been, however, to attempt to delimit the range of types which show the ‘crossed fibrillar’ structure typical of Valonia . It has been found possible, on the basis of wall characters, to divide the algae investigated into three rather ill-defined groups, as follows: Group 1. The algae of this group contain native cellulose (cellulose I) as a major skeletal substance. The cellulose is highly crystalline and shows the ‘crossed fibrillar’ organization. Members of this group are found only in the Cladophorales, and in a few members of the Siphonales. Group 2. The skeletal substance of the walls in this group possess intermolecular spacings which approximate to those of mercerized cellulose (cellulose II). There is some evidence that, in some cases at least, the substance is not mercerized cellulose but some cellulose derivative. It is poorly crystalline and normally in random orientation. The large bulk of the algae fall into this group, which includes the Spongomorpha section of Cladophora . Group 3. This is a small, heterogeneous collection of algae in which the skeletal substance either is not cellulose in any known form, or shows abnormalities, in what otherwise might be an X-ray diagram of cellulose, which make identification difficult. Prominent among the latter may be mentioned Spirogyra and Vaucheria . It is suggested that wall studies of this kind would repay consideration by taxonomists, particularly as regards the status of the Cladophorales,

scholarly journals Dissolution of cotton by 1-ethyl-3-methylimidazolium acetate studied with time–temperature superposition for three different fibre arrangements

Cellulose ◽  
2020 ◽  
Author(s):  
Yunhao Liang ◽  
James E. Hawkins ◽  
Michael E. Ries ◽  
Peter J. Hine
Keyword(s):  
Crystal Structure ◽  
Activation Energy ◽  
Cellulose Ii ◽  
X Ray Diffraction ◽  
Master Curves ◽  
Cellulose I ◽  
X Ray ◽  
Cotton Fibres ◽  
Temperature Superposition ◽  
Time Temperature Superposition

Abstract This study has investigated the dissolution of cotton fibres in the ionic liquid 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) for three fibre arrangements. Dissolution was carried out with excess [C2mim][OAc] at various temperatures and times followed by coagulation with water. Optical microscopy (OM) of the resulting processed and dried cotton fibres indicated that this procedure produced a coagulated fraction surrounding the original fibres. X-ray diffraction (XRD) showed that the crystal structure of this coagulated fraction was predominantly cellulose II, as opposed to the original fibres—mostly cellulose I. The OM and XRD results showed that growth of the coagulated fraction obeyed time–temperature superposition (TTS) and displayed an Arrhenius behaviour allowing a dissolution activation energy to be determined. Although the growth of the coagulated fraction with time were different for these distinct three arrangements, all could be individually shifted to form master curves using TTS, leading to very similar activation energies, 96 ± 3 kJ/mol (23 ± 1 kcal/mol). Graphic abstract

The Function of Swelling in the Finishing of Cotton

1969 ◽  
Vol 39 (6) ◽  
pp. 548-559 ◽  
Author(s):  
R. Jeffries ◽  
J. O. Warwicker
Keyword(s):  
Hydrogen Bond ◽  
Caustic Soda ◽  
Structural Changes ◽  
Cellulose Ii ◽  
Cellulose I ◽  
X Ray ◽  
Swelling Agent ◽  
Degree Of Swelling ◽  
Finishing Processes ◽  
Ray Methods

The mechanism of the interfibrillar and intrafibrillar swelling of cotton has been investigated by infrared and x-ray methods. Emphasis is on swelling in caustic soda, but other reagents are also considered. The presence of intrafibrillar swelling can be shown by detection of intermediate complex formation, while the swelling agents are present. The swelling behavior and the structural changes produced in the cotton are modified by the effects of tension and also by the presence of additives in the swelling solution. Whether the swelling complexes are intermediate in the conversion of cellulose I to cellulose II, or a reconversion to cellulose I results on washing out the swelling agent and drying, depends on the degree of swelling at different stages of the process. Intrafibrillar swelling is usually accompanied by an increase in the hydrogen-bond disorder, even if reconversion to cellulose I takes place, and the detection of this increase in disorder by ir-deuteration methods may be the only indication of an intrafibrillar swelling process. An explanation of the observed behavior is put forward in terms of the concept of cellulose sheets. The ideas developed from a study of the swelling of cotton by caustic soda and other swelling agents have been used in explaining the effects found in the mercerization and other finishing processes applied to cotton.

scholarly journals Detection and quantitation of cellulose II by Raman spectroscopy

2021 ◽  
Author(s):  
Umesh P. Agarwal ◽  
Sally A. Ralph ◽  
Carlos Baez ◽  
Richard S. Reiner
Keyword(s):  
Raman Spectroscopy ◽  
Crystalline Cellulose ◽  
Cellulose Ii ◽  
Raman Intensity ◽  
Cellulose I ◽  
X Ray ◽  
Pure Cellulose ◽  
Natural Cellulose ◽  
Intensity Ratios ◽  
Cellulose Materials

Abstract In cellulose materials, the cellulose II polymorph is often present either exclusively or inconjunction with cellulose I, the natural cellulose. Moreover, in regenerated andmercerized fibers (e,g., viscose and lyocell), natural cellulose adopts to the crystalstructure cellulose II Therefore, its detection and quantitation are important for acomplete assessment of such materials investigations. In the Raman spectra of suchmaterials, a band at 577 cm -1 is typically observed indicating the presence of thispolymorph. In the present study, to quantify the content of cellulose II, a calibrationmethod was developed based on the intensity of the 577 cm -1 peak relative to the1096 cm -1 band of cellulose. For this purpose, in addition to pure cellulose I andcellulose II samples (respectively, Avicel PH-101 and mercerized Avicel PH-101; hencereferred to as Avicel I and Avicel II), a set of five samples were produced by mixingthem in known quantities of Avicel I and Avicel II. The crystalline cellulose II contents ofthe samples were calculated based on the X-ray crystallinity of mercerized Avicel I.These seven samples were included in the calibration set and their Raman spectrawere obtained. Subsequently, Raman intensity ratios I 577 /I 1096 were calculatedby taking ratios of peak intensities at 577 and 1096 cm -1 . These ratios were plottedagainst the % of crystalline cellulose II present in the calibration set samples and thetwo were found to be linearly correlated (R 2 = 0.9944). The set-samples were alsoanalyzed using XRD which were then compared with the Raman method developedhere. Compared to XRD, the Raman method was found to be more sensitive atdetecting and quantifying cellulose II. Additionally, several cellulose II containingmaterials were analyzed by the new Raman method.

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