X-Ray Diffraction by Thermotropic Main-Chain Polymers Having Side Groups. Part A. Diffraction Theory

1988 ◽  
Author(s):  
Leonid V. Azaroff
Keyword(s):  
Main Chain ◽  
Diffraction Theory ◽  
X Ray Diffraction ◽  
X Ray ◽  
Main Chain Polymers

X-ray diffraction by thermotropic main-chain polymers with side groups. II. semiflexible polyesters

1989 ◽  
Vol 27 (10) ◽  
pp. 2001-2009 ◽  
Author(s):  
Hui H. Chin ◽  
Leonid V. Azároff ◽  
Agya R. Saini ◽  
Robert W. Lenz
Keyword(s):  
Main Chain ◽  
X Ray Diffraction ◽  
X Ray ◽  
Main Chain Polymers

X-ray diffraction properties of curved crystal diffractors

1992 ◽  
Vol 50 (2) ◽  
pp. 1734-1735
Author(s):  
W. Z. Chang ◽  
D. B. Wittry
Keyword(s):  
Diffraction Theory ◽  
X Rays ◽  
Diffraction Image ◽  
X Ray Diffraction ◽  
Rocking Curve ◽  
X Ray ◽  
Bent Crystal ◽  
Diffraction Geometry ◽  
Crystal Parameter ◽  
Quantitative Procedure

Since Du Mond and Kirkpatrick first discussed the principle of a bent crystal spectrograph in 1930, curved single crystals have been widely utilized as spectrometric monochromators as well as diffractors for focusing x rays diverging from a point. Curved crystal diffraction theory predicts that the diffraction parameters - the rocking curve width w, and the peak reflection coefficient r of curved crystals will certainly deviate from those of their flat form. Due to a lack of curved crystal parameter data in current literature and the need for optimizing the choice of diffraction geometry and crystal materials for various applications, we have continued the investigation of our technique presented at the last conference. In the present abstract, we describe a more rigorous and quantitative procedure for measuring the parameters of curved crystals.The diffraction image of a singly bent crystal under study can be obtained by using the Johann geometry with an x-ray point source.

Highlights in the history of X-ray topography1

1995 ◽  
Vol 210 (6) ◽  
Author(s):  
A. R. Lang
Keyword(s):  
Magnetic Domain ◽  
Diffraction Theory ◽  
Dislocation Loops ◽  
X Ray Diffraction ◽  
X Ray ◽  
Domain Structures ◽  
Structure Factors ◽  
History Of ◽  
Dislocation Sources ◽  
Non Destructive

AbstractX-ray topography provides a non-destructive method of mapping point-by-point variations in orientation and reflecting power within crystals. The discovery, made by several workers independently, that in nearly perfect crystals it was possible to detect individual dislocations by X-ray diffraction contrast started an epoch of rapid exploitation of X-ray topography as a new, general method for assessing crystal perfection. Another discovery, that of X-ray Pendellösung, led to important theoretical developments in X-ray diffraction theory and to a new and precise method for measuring structure factors on an absolute scale. Other highlights picked out for mention are studies of Frank-Read dislocation sources, the discovery of long dislocation helices and lines of coaxial dislocation loops in aluminium, of internal magnetic domain structures in Fe-3 wt.% Si, and of stacking faults in silicon and natural diamonds.

scholarly journals Thermal and optical properties of new poly(amide-imide)-nanocomposite reinforced by layer silicate based on chiral n-trimellitylimido-L-valine

2012 ◽  
Vol 31 (1) ◽  
pp. 79
Author(s):  
Khalil Faghihi ◽  
Masoumeh Soleimani ◽  
Shabnam Nezami ◽  
Meisam Shabanian
Keyword(s):  
Main Chain ◽  
Nanocomposite Films ◽  
Direct Polycondensation ◽  
Polycondensation Reaction ◽  
X Ray Diffraction ◽  
Solution Intercalation ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Polymeric Chains ◽  
Morphology And Structure

Two new samples of poly(amide-imide)-montmorillonite reinforced nanocomposites containing N-trimellitylimido-L-valine moiety in the main chain were synthesized by a convenient solution intercalation technique. Poly(amide-imide) (PAI) 5 as a source of polymer matrix was synthesized by the direct polycondensation reaction of N-trimellitylimido-L-valine (3) with 4,4′-diaminodiphenyl ether 4 in the presence of triphenyl phosphite (TPP), CaCl2, pyridine and N-methyl-2-pyrrolidone (NMP). Morphology and structure of the resulting PA-nanocomposite films (5a) and (5b) with 10 and 20 % silicate particles were characterized by FTIR spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effect of clay dispersion and the interaction between clay and polymeric chains on the properties of nanocomposite films were investigated by using Uv-vis spectroscopy,  thermogravimetric analysis (TGA) and water uptake measurements.

scholarly journals Synthesis of Polyazobenzenes Exhibiting Photoisomerization and Liquid Crystallinity

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 348 ◽  
Author(s):  
Masashi Otaki ◽  
Reiji Kumai ◽  
Hajime Sagayama ◽  
Hiromasa Goto
Keyword(s):  
Conjugated Polymers ◽  
Main Chain ◽  
Cross Coupling ◽  
Industrial Applications ◽  
Optical Absorption Spectroscopy ◽  
X Ray Diffraction ◽  
Liquid Crystallinity ◽  
X Ray ◽  
Cis And Trans ◽  
Chain Type

While only a few studies have investigated the synthesis of main chain-type polyazobenzenes, they continue to draw an increasing amount of attention owing to their industrial applications in holography, dyes, and functional adhesives. In this study, dibromoazobenzene was prepared as a monomer for constructing azo-based π-conjugated polymers. Miyaura–Suzuki cross-coupling polymerization was conducted to develop copolymers containing an azobenzene unit as a photoisomerization block and a pyrimidine-based liquid crystal generator block. The prepared polymers exhibited thermotropic liquid crystallinity and underwent cis and trans photoisomerization upon irradiation with ultraviolet and visible light. Furthermore, the photoisomerization behavior was examined using optical absorption spectroscopy and synchrotron X-ray diffraction spectrometry.

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