A fitting method for the determination of crystallinity by means of X-ray diffraction

1990 ◽  
Vol 23 (5) ◽  
pp. 359-365 ◽  
Author(s):  
S. Polizzi ◽  
G. Fagherazzi ◽  
A. Benedetti ◽  
M. Battagliarin ◽  
T. Asano
Keyword(s):  
Diffraction Method ◽  
Integral Form ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Acta Cryst ◽  
X Ray ◽  
Amorphous Sample ◽  
Continuous Background ◽  
The Degree Of Crystallinity

A best-fitting version of the X-ray diffraction method of Gehrke & Zachmann [Makromol. Chem. (1981). 182, 627–635] for crystallinity determination, which is a modification of the method developed by Ruland [Acta Cryst. (1961). 14, 1180–1185], is presented. The data, corrected and normalized to electron units (e.u.), are plotted as I(s)s 2 vs s and fitted by pseudo-Voigt functions for the crystalline peaks added to a background scattering IB (s)s 2, with IB (s) = (1 − Xc )I am(s) + Xc 〈f(s)2〉[1 − exp(−ks 2)], where I am is the experimental intensity of a completely amorphous sample (also corrected and normalized to e.u.), 〈f(s)2〉 is the mean square atomic scattering factor in the material, Xc is the degree of crystallinity and k is a factor which includes either thermal or lattice disorder, where s = 2(sin θ)/λ. The use of the scattering of the amorphous sample in this non-integral form of the Ruland equations overcomes the problem, encountered with other procedures, of locating the continuous (background) scattering with accuracy. The degree of crystallinity and the disorder factor are supplied directly by the optimization process. Furthermore, the line broadening analysis which allows the determination of crystallite size is automatically obtained as a by product. Samples of polyethylene terephthalate (PET) with different degrees of crystallinity are investigated. The results are compared with those obtained by other methods which do not use fitting techniques.

scholarly journals Determination of the Degree of Crystallinity of Poly(2-methyl-2-oxazoline)

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4356
Author(s):  
Evgeniy M. Chistyakov ◽  
Sergey N. Filatov ◽  
Elena A. Sulyanova ◽  
Vladimir V. Volkov
Keyword(s):  
Thermal Destruction ◽  
Polymer Melt ◽  
Boron Trifluoride Etherate ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Cationic Ring Opening Polymerization ◽  
The Degree Of Crystallinity

A new method for purification of 2-methyl-2-oxazoline using citric acid was developed and living cationic ring-opening polymerization of 2-methyl-2-oxazoline was carried out. Polymerization was conducted in acetonitrile using benzyl chloride—boron trifluoride etherate initiating system. According to DSC data, the temperature range of melting of the crystalline phase of the resulting polymer was 95–180 °C. According to small-angle X-ray scattering and wide-angle X-ray diffraction data, the degree of crystallinity of the polymer was 12%. Upon cooling of the polymer melt, the polymer became amorphous. Using thermogravimetric analysis, it was found that the thermal destruction of poly(2-methyl-2-oxazoline) started above 209 °C.

Digital Filtering and Shape Identification in the Analysis of WAXD Patterns of Semicrystalline Polymers

2013 ◽  
Vol 203-204 ◽  
pp. 189-192 ◽  
Author(s):  
Małgorzata Rabiej
Keyword(s):  
Numerical Differentiation ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Amorphous Halo ◽  
Shape Identification ◽  
Diffraction Curve ◽  
X Ray ◽  
The Degree Of Crystallinity ◽  
Quick Determination

Most frequently, the degree of crystallinity of polymers is determined using Wide Angle X-ray Diffraction (WAXD) technique. The method consists in the resolution of WAXD diffraction curve of a polymer into individual crystalline peaks and amorphous halo. This work presents a procedure, which was elaborated to help in a quick determination of the angular positions of crystalline peaks present in the diffraction curve of investigated polymer. The positions of peaks are determined using numerical differentiation. Using these data the computer program WAXSFIT identifies investigated polymer and prepares a set of starting parameters which are used in the calculations of the degree of crystallinity.

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%.

X-ray diffraction determination of the degree of crystallinity of cellulose using a computer

1992 ◽  
Vol 24 (1) ◽  
pp. 80-85 ◽  
Author(s):  
A. Sh. Goikhman ◽  
V. M. Irklei ◽  
O. S. Vavrinyuk ◽  
V. I. Pirogov
Keyword(s):  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Determination ◽  
The Degree Of Crystallinity

scholarly journals Magnetically Oriented Powder Crystal to Indexing and Structure Determination

2014 ◽  
Vol 70 (a1) ◽  
pp. C1560-C1560
Author(s):  
Fumiko Kimura ◽  
Wataru Oshima ◽  
Hiroko Matsumoto ◽  
Hidehiro Uekusa ◽  
Kazuaki Aburaya ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Crystal Lattice ◽  
Powder Diffraction ◽  
Diffraction Method ◽  
Lattice Parameters ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystal Lattice Parameters

In pharmaceutical sciences, the crystal structure is of primary importance because it influences drug efficacy. Due to difficulties of growing a large single crystal suitable for the single crystal X-ray diffraction analysis, powder diffraction method is widely used. In powder method, two-dimensional diffraction information is projected onto one dimension, which impairs the accuracy of the resulting crystal structure. To overcome this problem, we recently proposed a novel method of fabricating a magnetically oriented microcrystal array (MOMA), a composite in which microcrystals are aligned three-dimensionally in a polymer matrix. The X-ray diffraction of the MOMA is equivalent to that of the corresponding large single crystal, enabling the determination of the crystal lattice parameters and crystal structure of the embedded microcrytals.[1-3] Because we make use of the diamagnetic anisotropy of crystal, those crystals that exhibit small magnetic anisotropy do not take sufficient three-dimensional alignment. However, even for these crystals that only align uniaxially, the determination of the crystal lattice parameters can be easily made compared with the determination by powder diffraction pattern. Once these parameters are determined, crystal structure can be determined by X-ray powder diffraction method. In this paper, we demonstrate possibility of the MOMA method to assist the structure analysis through X-ray powder and single crystal diffraction methods. We applied the MOMA method to various microcrystalline powders including L-alanine, 1,3,5-triphenyl benzene, and cellobiose. The obtained MOMAs exhibited well-resolved diffraction spots, and we succeeded in determination of the crystal lattice parameters and crystal structure analysis.

An X-ray Diffraction Method for the Determination of Temperatures in Coke Reactions

1984 ◽  
Vol 28 ◽  
pp. 383-388 ◽  
Author(s):  
Jack L. Johnson ◽  
Seymour Katz
Keyword(s):  
Diffraction Method ◽  
Temperature History ◽  
Maximum Temperature ◽  
Slag Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Potential Source ◽  
History Of ◽  
Extract Information

Information about the conditions and reactions in a foundry cupola is essential to understand the thermochemistry of a cupola and thus improve its efficiency. A potential source of such information is coke taken from inside an operating cupola. In the region of the cupola that extends from the melt zone to the taphole, coke is directly involved in important chemical processes such as combustion, gasification, slag formation, iron sulfurization, carbon pickup, and oxide reduction. Coke is also suspected of being involved in the transport of silicon to the liquid iron. Each of these processes produces characteristic physical and/or chemical changes in the coke, making it possible to extract information about the processes from an examination of coke pieces taken from within an operating cupola. A program to study such coke samples is in progress. To effectively interpret these data it is necessary to know the temperature history of the coke being examined, especially the maximum temperature attained by the coke piece in the cupola.

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