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.

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.

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

Structure Determination of B4C and SiC Thin Films Via Synchrotron High-Resolution Diffraction

1997 ◽  
Vol 505 ◽  
Author(s):  
J. Hershberger ◽  
F. Kustas ◽  
Z. U. Rek ◽  
S. M. Yalisove ◽  
J. C. Bilello
Keyword(s):  
Thin Films ◽  
Average Density ◽  
Distribution Functions ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Double Crystal ◽  
X Ray ◽  
Si Substrates ◽  
X Ray Scattering

ABSTRACTThin films of B4C and SiC deposited by magnetron sputtering as components of multilayers have the potential to provide significant property improvements over current wear resistant coating technology. B4C and SiC have previously been found to be amorphous and possibly nanocrystalline under the deposition conditions used. This study reports results of synchrotron x-ray scattering experiments providing information on the degree of crystallinity, strain, average density, and coordination number in 2000 Å films of these compounds on Si substrates. Radial distribution functions from B4C and SiC thin films were obtained and used to model the structure. Strain results are compared with Double Crystal x-ray Diffraction Topography (DCDT) results as a means for establishing a standard strain state.

scholarly journals Hemp Fibre Reinforced Poly(Lactic Acid) Composites

2007 ◽  
Vol 29-30 ◽  
pp. 337-340 ◽  
Author(s):  
M.A. Sawpan ◽  
K.L. Pickering ◽  
Alan Fernyhough
Keyword(s):  
Lactic Acid ◽  
Degree Of Crystallinity ◽  
Poly Lactic Acid ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Hemp Fibre ◽  
Reinforcing Material ◽  
Fibre Loading ◽  
The Degree Of Crystallinity

The potential of hemp fibre as a reinforcing material for Poly(lactic acid) (PLA) was investigated. Good interaction between hemp fibre and PLA resulted in increases of 100% for Young’s modulus and 30% for tensile strength of composites containing 30 wt% fibre. Different predictive ‘rule of mixtures’ models (e.g. Parallel, Series and Hirsch) were assessed regarding the dependence of tensile properties on fibre loading. Limited agreement with models was observed. Differential scanning calorimetry (DSC) and x-ray diffraction (XRD) studies showed that hemp fibre increased the degree of crystallinity in PLA composites.

Study of the structure and thermal characteristics of nanocomposites based on polyvinyl alcohol and intercalated montmorillonite

2019 ◽  
pp. 089270571987919
Author(s):  
Volodymyr Krasinskyi ◽  
Ivan Gajdos ◽  
Oleh Suberlyak ◽  
Viktoria Antoniuk ◽  
Tomasz Jachowicz
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Acrylic Acid ◽  
Polyvinyl Alcohol ◽  
Thermal Characteristics ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
The Degree Of Crystallinity

The structure and thermal characteristics of nanocomposites based on polyvinyl alcohol (PVA) and montmorillonite (MMT) intercalated with polyvinylpyrrolidone were investigated by X-ray diffraction analysis and differential scanning calorimetry. The modification of PVA with intercalated MMT reduces the degree of crystallinity of the resulting nanocomposites but significantly increases their thermal stability. Under ultrasound, the intercalated MMT was completely distributed in a PVA solution and formed a monocrystalline structure. Films based on PVA with modified MMT were cross-linked at 110°C in the presence of 5 wt% acrylic acid and 0.5 wt% Ferrous(II) sulfate as an initiator. The formed films have a homogeneous cross-linked structure.

scholarly journals X-Ray Diffraction Studies on Alicyclic Saturated Discotic Liquid Crystals

1987 ◽  
Vol 42 (6) ◽  
pp. 631-635 ◽  
Author(s):  
H. W. Neuling ◽  
H. Stegemeyer ◽  
K. Praefcke ◽  
B. Kohne
Keyword(s):  
Liquid Crystalline ◽  
Optical Observations ◽  
X Ray Diffraction ◽  
X Ray ◽  
Alkyl Chains ◽  
New Class ◽  
X Ray Scattering ◽  
Oriented Samples ◽  
Hexagonal Columnar

The discotic liquid crystalline phase of a new class of disc-like molecules (hexa-O-alkanoylscyllo- inositoles) is studied by small angle X-ray scattering, DSC and optical observations. Comparison of these three methods allows the determination of the structural arrangement. X-ray film exposures of oriented samples clearly demonstrate the hexagonal columnar ordered type of mesophases. A simple model calculation shows that the alkyl chains of neighbouring columns interpenetrate each other to a small extent.

Determination of the cationic distribution in oxidic thin films by resonant X-ray diffraction: the magnetoelectric compound Ga2−xFexO3

2016 ◽  
Vol 49 (4) ◽  
pp. 1308-1314 ◽  
Author(s):  
Christophe Lefevre ◽  
Alexandre Thomasson ◽  
Francois Roulland ◽  
Vincent Favre-Nicolin ◽  
Yves Joly ◽  
...  
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Element Distribution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Site Distribution ◽  
X Ray Scattering ◽  
Cationic Distribution ◽  
Cationic Site

The cationic distribution is decisive for both the magnetic and electric properties of complex oxides. While it can be easily determined in bulk materials using classical methods such as X-ray or neutron diffraction, difficulties arise for thin films owing to the relatively small amount of material to probe. It is shown here that a full determination of the cationic site distribution in thin films is possible through an optimized processing of resonant elastic X-ray scattering experiments. The method is illustrated using gallium ferrite Ga2−xFexO3samples which have been the focus of an increasing number of studies this past decade. They indeed represent an alternative to the, to date, only room-temperature magnetoelectric compound BiFeO3. The methodology can be applied to determine the element distribution over the various crystallographic sites in any crystallized system.

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