scholarly journals ANALYSIS OF STRUCTURAL CHANGES OF CELLULOSE COMPONENT IN PROCESS OF ELEMENTARIZATION OF FLAX FIBERS

2017 ◽  
Vol 60 (6) ◽  
pp. 102 ◽  
Author(s):  
Alexandr E. Zavadskii ◽  
Valeria G. Stokozenko ◽  
Andrey P. Moryganov ◽  
Igor Yu. Larin
Keyword(s):  
Supramolecular Structure ◽  
Structural Changes ◽  
Raw Materials ◽  
Diffraction Method ◽  
Degree Of Crystallinity ◽  
X Ray ◽  
Flax Fibers ◽  
Cellulose Iβ ◽  
Deep Purification ◽  
Cellulose Component

The comparative research of composition and supramolecular structure of the flax fibers received by methods of a cottonization and a mechanical elementarization under the influence of the cyclic deforming loadings was conducted. It was shown that under the influence of cyclic loadings removal of a considerable part of impurity with the increase in content of cellulose to 80.1% is reached. At the same time, division of complexes onto elementary filament provides the increase in the total surface of material and, as a result, to availability of fibers to the reagents at the subsequent alkaline boiling. X-ray analysis of flax samples with a method of comparison of the normalized parameters of diffraction by crystalline regions of cellulose allowed to establish that degree of crystallinity of a cellulose component of fibers remains constant even at deep purification of raw materials under the influence of cyclic deformations and subsequent boiling. The research of the oriented fibers by X-ray diffraction method has shown that removal of impurity from flax in the course of an elementarization has only weak influence on the sizes of crystallites of cellulose. The increase in the cross sizes of crystallites by 4 – 6% was observed at deep purification of fibers due to the boiling. This phenomenon can be connected with the decrease in influence of a diffraction maximum from impurity on half-width of the equatorial reflex 200 for cellulose Iβ. It should be noted that the longitudinal sizes of crystallites at the same time do not change. It was suggested on possible influence of decrease in content of impurity on supramolecular structure of an amorphous phase of cellulose and as a result on the observed growth of sorption and mechanical properties of flax fibers at an elementarization by method of cyclic deformation.Forcitation:Zavadskii A.E., Stokozenko V.G., Moryganov A.P., Larin I.Yu. Analysis of structural changes of cellulose component in process of elementarization of flax fibers. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 6. P. 102-108.

Radiation-Modification Impact on the Filled Polytetrafluoroethylene Structure and Mechanical Strength

2017 ◽  
Vol 736 ◽  
pp. 29-34 ◽  
Author(s):  
A.P. Morgunov ◽  
I.V. Revina
Keyword(s):  
Electron Microscopy ◽  
Tensile Strength ◽  
Structural Analysis ◽  
Mechanical Strength ◽  
Supramolecular Structure ◽  
Structural Changes ◽  
Tensile Modulus ◽  
Radiation Energy ◽  
Degree Of Crystallinity ◽  
X Ray

The article studies the structure and properties, regularities of their change with the introduction of various fillers and under the influence of gamma – irradiation (γ-radiation). PCM structure study was performed using electron microscopy with scanning electron microscope BS -350 (TESLA) and with X-ray structural analysis method using X-ray diffractometer DRON-3. Shooting of wide-angle X-ray patters was performed in the range of Bragg angles reflection 2Q=5° - 96°. We selected the following properties to study: tensile strength, static tensile modulus. The findings allowed determining: firstly, we determined that based on electron microscopy the supramolecular structural organization depends on the type and percentage of filler in PTFE matrix. Changes take place from lamellar (pure PTFE) to a defective spherulitic (20% of coke) structure. Secondly, we completed X-ray structural analysis (we determined the degree of crystallinity, crystallite size, with parameters а = b in the hexagonal cell, interlayer distance of amorphous area) showed the nature of supramolecular structure changes according to the nature of the filler and subsequent radiation dose. Thirdly there was conducted connection between changes in mechanical strength (tensile strength, statical module of elasticity) and structural changes; the depth of these changes depends on the original supramolecular structure, type and percentage of the filler and the dose of the absorbed radiation energy. The studies will allow change purposefully the supramolecular structure of polymer composite materials to improve the performance properties.

XRD investigation of thermal degradation of some gamma-irradiated polyethylene terephthalate samples

2019 ◽  
Vol 33 (12) ◽  
pp. 1950111 ◽  
Author(s):  
Mihai Todica ◽  
Zoltan Kovacs-Krauss ◽  
Carmen Niculaescu ◽  
Marieta Mureşan-Pop
Keyword(s):  
Thermal Treatment ◽  
Polyethylene Terephthalate ◽  
Structural Changes ◽  
Diffraction Method ◽  
Resonance Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Before And After ◽  
Gamma Irradiated ◽  
Different Doses

The modification of local structure of some commercial polyethylene terephthalate (PET) samples, gamma irradiated at different doses, was investigated by X-ray diffraction method before and after thermal treatment. Before the thermal treatment, the samples exposed to different doses of gamma radiations, does not show noticeable structural changes. However, the gamma exposure affects the thermal behavior of samples submitted to melting–cooling process. These modifications have been highlighted by X-ray diffraction, and confirmed also by thermal analysis and electron spin resonance spectroscopy.

scholarly journals Application of Isothermal and Isoperibolic Calorimetry to Assess the Effect of Zinc on Hydration of Cement Blended with Slag

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2930 ◽  
Author(s):  
Šiler ◽  
Kolářová ◽  
Novotný ◽  
Másilko ◽  
Bednárek ◽  
...  
Keyword(s):  
Cement Hydration ◽  
Raw Materials ◽  
Isothermal Calorimetry ◽  
Real Life ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Isoperibolic Calorimetry ◽  
Poorly Soluble ◽  
Furnace Slag

This work deals with the influence of zinc on cement hydration. The amount of zinc in cement has increased over recent years. This is mainly due to the utilization of solid waste and tires, which are widely used as a fuel in a rotary kiln. Zinc can also be introduced to cement through such secondary raw materials as slag, due to increased recycling of galvanized materials. The aim of this work was to determine the effect of zinc on the hydration of Portland cement, blended with ground blast furnace slag (GBFS). This effect was studied by isothermal and isoperibolic calorimetry. Both calorimetry methods are suitable for measurements during the first days of hydration. Isoperibolic calorimetry monitors the hydration process in real-life conditions, while isothermal calorimetry does so at a defined chosen temperature. Zinc was added to the cement in the form of two soluble salts, namely Zn(NO3)2, ZnCl2, and a poorly soluble compound, ZnO. The concentration of added zinc was chosen to be 0.05, 0.1, 0.5, and 1mass percent. The amount of GBFS replacement was 15% of cement dosage. The newly formed hydration products were identified by X-ray diffraction method (XRD).

scholarly journals Effect of the acetylation process on native starches of yam (Dioscorea spp.)

2016 ◽  
Vol 69 (2) ◽  
pp. 7997-8006 ◽  
Author(s):  
Jairo Salcedo Mendoza ◽  
Jorge Hernández RuyDiaz ◽  
Alfredo Fernández Quintero
Keyword(s):  
Structural Changes ◽  
Raw Materials ◽  
Amylose Content ◽  
Reaction Times ◽  
Absorption Capacity ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Modified Starches ◽  
Granule Morphology ◽  
Low Degrees

In Colombia, it is necessary to produce native and modified starches for the use of amylaceous raw materials of major socioeconomic importance. In this study, the effects of the acetylation process on structural, morphological and functional properties of native starches yam, Dioscorea spp. (D. alata and D. rotundata) were evaluated. Chemical modification by esterification with acetic anhydride was performed at different reaction times, and morphological and structural changes were assessed using the following techniques: infrared spectroscopy (FTIR), X-ray diffraction and scanning electron microscopy (SEM). Acetylation produced slight changes in the granule morphology, and a decreased degree of crystallinity (DC) associated with a slight increase in the amylose content was observed. The introduction of acetyl groups into the starch structure caused a decrease in the gelatinization temperature and an increased retro gradation tendency. The acetylated starches had low degrees of substitution (DS<0.2), meaning they can be used in the food industry, considering that they showed greater stability, greater water absorption capacity and better solubility than native starches.

Effect of Alkali Treatment on Crystalline Structure of Cellulose Fiber from Mendong (Fimbristylis globulosa) Straw

2013 ◽  
Vol 594-595 ◽  
pp. 720-724 ◽  
Author(s):  
Heru Suryanto ◽  
Eko Marsyahyo ◽  
Yudy Surya Irawan ◽  
Rudy Soenoko
Keyword(s):  
Crystalline Structure ◽  
Alkali Treatment ◽  
Diffraction Method ◽  
Cellulose Fiber ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Naoh Solution ◽  
The Degree Of Crystallinity ◽  
Treatment Concentration

The research aim is to investigate the effect of alkali treatment on the crystalline structure of Mendong fiber. The experiment was conducted by immerse fibers in 100 ml NaOH solution by a concentration of 2.5%, 5%, 7.5%, and 10% for 2 hours at the room temperature. The specimens were characterized by X-ray diffraction method. The morphology of fiber treated by alkali was observed by Scanning Electron Microscope. The result shows that the crystalline structure of cellulose in Mendong fiber was changed in alkali treatment. It was found that both the degree of crystallinity and crystalline index of Mendong fiber was increased until alkali treatment concentration of 7.5%.

scholarly journals X-RAY STRUCTURAL ANALYSIS OF COTTONS AND HERBACEOUS CELLULOSE

2021 ◽  
pp. 61-71
Author(s):  
Kseniya Sergeyevna Momziakova ◽  
Aleksey Aleksandrovich Shinkarev ◽  
Timur Rustamovich Deberdeev ◽  
Zimfira Talgatovna Valishina ◽  
Aleksandr Aleksandrovich Berlin ◽  
...  
Keyword(s):  
Transverse Direction ◽  
Raw Materials ◽  
Correlation Coefficients ◽  
Coherent Scattering ◽  
High Viscosity ◽  
Degree Of Polymerization ◽  
Degree Of Crystallinity ◽  
Hammer Mill ◽  
Mechanical Destruction ◽  
X Ray

It was found that the extrusion treatment of cotton cellulose in an aqueous medium, followed by drying and grinding on a hammer mill leads to a decrease in the crystallite size in the transverse direction ([110] and [100]) as a result of mechanical destruction of cellulose macromolecules, and the subsequent acid hydrolysis of cellulose in H2SO4 solutions to an increase in the size of crystallites in the transverse direction ([110], [110] and [100]) due to co-crystallization processes. It is shown that alkaline cooking of cellulose-containing material, followed by extrusion processing, washing, drying and grinding on a hammer mill leads to an increase in the transverse dimensions of crystallites in the [110] and [100] directions for flax cellulose and in the [110], [110] and [100] – for cellulose from oats and alfalfa as a result of partial removal of lignin and hemicelluloses from the cellulose-containing material. Differences were revealed in the sizes of the coherent scattering regions and the parameters of the crystallographic cell of cellulose samples from cotton and herbaceous plants (flax, oats, and alfalfa), as well as between samples from oats and alfalfa obtained under the same conditions with the same type of feedstock (straw). It has been established that the proposed stepwise technology for processing cotton and linen fibers leads to a slight decrease in the degree of crystallinity and the average degree of polymerization, which indicates that the developed technology for obtaining high-viscosity powder celluloses for various purposes is promising. Correlation coefficients are established between the values of the degree of ordering of the structure of cellulose samples from various plant raw materials, calculated using X-ray diffraction analysis and FT-IR spectroscopy, which make it possible to adequately compare all the known literature and experimental data.

Effect of Partial Substitution of Sr by Ba on the Structural Properties of Tl0.8Ni0.2Sr2-xBrxCa2Cu3O9-δ System

2021 ◽  
Vol 900 ◽  
pp. 172-179
Author(s):  
Mohammed Abdul Nebi Thejeel ◽  
Rihab Nassr Fadhil ◽  
Shatha H. Mahdie ◽  
Kareem Ali Jasim ◽  
Auday H. Shaban
Keyword(s):  
Structural Properties ◽  
Crystal Size ◽  
Full Width Half Maximum ◽  
Raw Materials ◽  
Degree Of Crystallinity ◽  
Partial Substitution ◽  
X Ray Diffraction ◽  
Solid State Reaction Technique ◽  
X Ray ◽  
Barium Concentration

In this manuscript, the effect of substituting strontium with barium on the structural properties of Tl0.8Ni0.2Sr2-xBrxCa2Cu3O9-δ compound with x= 0, 0.2, 0.4, have been studied. Samples were prepared using solid state reaction technique, suitable oxides alternatives of Pb2O3, CaO, BaO and CuO with 99.99% purity as raw materials and then mixed. They were prepared in the form of discs with a diameter of 1.5 cm and a thickness of (0.2-0.3) cm under pressures 7 tons / cm2, and the samples were sintered at a constant temperature of 860 ° C. The structural properties were studied using X-ray diffraction for all samples, and the results showed that the samples have tetragonal structure and the change of the parameters structure with the change of the barium concentration. Full Width Half Maximum (FWHM) was calculated by Orange Pro using X-RAY data. The crystal size was calculated using Scherrer and Willeamson-Heall methods, where the results showed that the crystal size, compliance and degree of crystallinity changed with the change of barium concentration, and the highest average for the crystal size was 70.0271nm at x=0, and crystallization at 61.46% at x=0.6, and the strain decreased to 0.0037 when barium concentration equals 0.4.

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