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.

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.

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

X-Ray Determination of Crystallinity in Deformed Rubber

1955 ◽  
Vol 28 (4) ◽  
pp. 999-1006 ◽  
Author(s):  
S. C. Nyburg
Keyword(s):  
Heat Treatment ◽  
Pure Shear ◽  
Degree Of Crystallinity ◽  
Simple Extension ◽  
Amorphous Halo ◽  
Volume Changes ◽  
X Ray ◽  
Constant Deformation ◽  
The Degree Of Crystallinity

Abstract A vulcanized natural rubber has been deformed in simple extension and in pure shear and the resulting diminution of x-ray intensity of the amorphous halo used as a measure of crystallinity. The effect of mode of deformation and attempts to reach equilibrium states by heat treatment at constant deformation are described. The values obtained for simple extension are in accord with those reported by Goppel and not with those of Field. The degree of crystallinity is greater in pure shear than in simple extension at the same principal extension ratio. Corrected values for the orientation of crystalline regions have been obtained, and a comparison is made between volume changes and x-ray measurements for simple extension.

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 Microwave-Assisted Preparation of Zinc-Doped β-Tricalcium Phosphate for Orthopedic Applications

2020 ◽  
Author(s):  
Ali Taha Saleh ◽  
Dheyaa Alameri
Keyword(s):  
Tricalcium Phosphate ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Assisted ◽  
Ftir Spectrometer ◽  
Diffraction Peaks ◽  
Orthopedic Applications ◽  
The Degree Of Crystallinity ◽  
Good Agreement

A novel two-step methodology delivering zinc into the structure of β-tricalcium phosphate (β-TCP) has been investigated. Incorporating wet precipitation of calcium-deficient apatite [Ca9-xZnx(HPO4)(PO4)5(OH)] (x = 0.00–1.00 mol) using a microwave-assisted process followed by two-hour calcination at 1000 °C has been conducted to generate a ratio of 1.48 of Zn doped β-TCP. The products were characterized by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectrometer, and field emission scanning electron microscope (FESEM). Our results confirmed that the product was crystalline Zn2+-doped β-tricalcium phosphate. The incorporation of Zn+2 into the β-TCP lattice resulted in a shifting of diffraction peaks to higher 2θ values, which were attributed to the substitution of larger-sized Ca+2 ions with smaller-sized Zn2+ ions. A reduction in the intensity of the XRD peaks was also observed due to the reduction in the degree of crystallinity of the samples. Lattice parameters along the a and c-axis showed a gradual decrease in length with an increase in the amount of Zn2+ doping. This decrease was attributed to the replacement of Ca+2 ion by the smaller-sized Zn2+ ions. The microstructure of the powders consisted of microscale aggregates fused together. EDX analysis of all samples showed that the Zn2+ doping had successfully taken place and the amount of Zn2+ present in the samples was in good agreement with the theoretical values.

Computer Capability for the Determination of Polymer Crystallinity by X-Ray Diffraction

1985 ◽  
Vol 29 ◽  
pp. 281-290
Author(s):  
Andrew M. Wims ◽  
Mark E. Myers ◽  
Jack L. Johnson ◽  
Julia M. Carter
Keyword(s):  
Room Temperature ◽  
Physical And Mechanical Properties ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Percent Elongation ◽  
X Ray ◽  
Reinforcing Fillers ◽  
Crystalline Domains ◽  
Polymer Crystallinity

The physical and mechanical properties of many industrially important polymers are profoundly influenced by their degree of crystallinity; such properties include flex modulus, tensile strength, percent elongation, and impact strength. Commonly used polymers influenced by their crystallinity level include polyethlene, polypropylene, polyesters, and nylons. Many of these materials are above their glass transition temperature at room temperature and would be useless were it not for their crystalline phase which typically has a melting point far above room temperature. The crystalline ‘ regions (domains) in these materials are frequently very small, typically in the nanometer range in diameter. These crystalline domains act as reinforcing fillers (in somewhat the same manner as carbon black In rubber) and give strength to the polymer.

Sign in / Sign up

Export Citation Format

Share Document