The Rubber-like Behavior of an Artificial Substance (Oppanol) when Irradiated with X-rays

1938 ◽  
Vol 11 (4) ◽  
pp. 687-688
Author(s):  
R. Brill ◽  
F. Halle
Keyword(s):  
Natural Rubber ◽  
Normal State ◽  
X Rays ◽  
Organic Substances ◽  
Chain Molecules ◽  
X Ray ◽  
Natural Substances ◽  
Amorphous Sulfur ◽  
Definite Temperature ◽  
Long Chain

Abstract As is known, natural rubber has the property of giving, when stretched, an x-ray fiber diagram, whereas in a normal state the same rubber is amorphous. Numerous other natural substances such as hair and tendon, and artificial substances such as polychloroprene, behave in the same way. However, this effect is not confined to purely organic substances, and it is to be found, for example, in the case of so-called amorphous sulfur and polyphosphornitryl chloride (PNCl2)x. All these substances have the property in common with one another of exhibiting a rubber-like elasticity within a definite temperature range, and of being composed of long-chain molecules.

Properties of Some Synthetic Rubbers

1943 ◽  
Vol 16 (4) ◽  
pp. 857-862
Author(s):  
L. B. Sebrell ◽  
R. P. Dinsmore
Keyword(s):  
Molecular Structure ◽  
Natural Rubber ◽  
Point Of View ◽  
General Point ◽  
Chain Molecules ◽  
X Ray ◽  
Synthetic Rubber ◽  
The Difference ◽  
Diffraction Patterns ◽  
Long Chain

Abstract X-RAY STRUCTURE OF SYNTHETIC RUBBER In presenting a series of x-ray diagrams of various types of synthetic rubber in comparison with natural rubber, in both the stretched and the unstretched condition, it is our purpose to bring out the fact that the molecular structure of synthetic rubbers is entirely different from that of natural rubber. It is proposed also to review briefly the theories which have been advanced, based on the x-ray analysis of rubber, to account for the elasticity of natural rubber, and to advance the possible reason for the difference shown by the x-ray diagrams of synthetic rubber. At the present time, from the most general point of view, the molecular structure of a rubberlike material is envisaged as a sort of brush-heap structure of entangled long chain molecules. x-Ray diffraction patterns show that, for some rubberlike materials, notable regularities of structure sometimes occur in the tangle of long-chain molecules. It is now realized that these regularities are not essential for rubberlike behavior. Nevertheless their observation and study is important because they afford a unique opportunity for studying the molecular structure of the chains and the molecular rearrangements which occur with the application of stress.

X-Ray Diffraction Patterns of Crystalline Sol Rubber Prepared from Ethereal Solution

1939 ◽  
Vol 12 (3) ◽  
pp. 482-484
Author(s):  
George L. Clark ◽  
Siegfried T. Gross ◽  
W. Harold Smith
Keyword(s):  
Sol Gel ◽  
Crystalline Material ◽  
X Rays ◽  
X Ray Diffraction ◽  
Experimental Procedure ◽  
Chain Molecules ◽  
X Ray ◽  
Measurement And Analysis ◽  
Diffraction Patterns ◽  
Long Chain

Abstract In a previous publication there was reproduced an x-ray diffraction pattern of crystals obtained from a solution, cooled to temperatures between −40° and −50° C, of an ether-gel fraction of rubber from Hevea brasiliensis. Measurements of three strong interferences indicated that the crystals were similar to those of stretched gel rubber and of frozen sol, gel and total rubber. Although many attempts were made at that time, unsatisfactory diffraction patterns were obtained with crystalline ether-sol rubber. The interferences were faint and not suitable for accurate measurement and analysis. Since the crystalline material is bulky and some specimens are more compact than others, it seemed possible that the average number of cell diameters was too small to permit sharp definition, and that more material was required for the examination by x-rays. However, it is not certain that lack of definition was caused by insufficient crystalline rubber. The possibility that parts of the long-chain molecules become crystalline and that parts remain amorphous is not excluded, and might be its cause. Additional work with crystalline sol rubber, using a slightly different experimental procedure and more material than in earlier experiments, finally resulted in a satisfactory pattern.

To the question of the treatment of surgical tbc

1926 ◽  
Vol 22 (5-6) ◽  
pp. 737
Author(s):  
I. Friedland
Keyword(s):  
Fatty Acids ◽  
Adrenal Gland ◽  
Fish Oil ◽  
Healthy Subject ◽  
Normal State ◽  
Adrenal Glands ◽  
X Rays ◽  
Subcutaneous Injections ◽  
X Ray

Arikhbaev (Vesti. Khir., 1926, book 17-18), having established the normal state of the lipolytic index in 30 people with various diseases and then proceeding to the determination of lipase in the blood of 9 various patients and 1 healthy subject exposed to irritating doses of X-ray rays on the adrenal gland, which caused its hyperfunction, finished his research by observing 5 patients with various forms of surgical tuberculosis, of whom three underwent simultaneous x-rays of the adrenal glands with subcutaneous injections of fish oil neutralized from fatty acids, one - only injections of neutralized fish oil and one - only an operational aid.

scholarly journals On the structure of multilayers. Part I

1940 ◽  
Vol 176 (967) ◽  
pp. 534-542 ◽  
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Angle Of Incidence ◽  
X Rays ◽  
Ethyl Stearate ◽  
X Ray ◽  
Entire Thickness ◽  
Long Chain

X -ray and microscopic examinations of multilayers of certain long-chain esters deposited on transparent bases have been made. An X -ray photograph of a stationary multilayer of ethyl stearate is apparently identical with that obtained by rotating a single crystal of β -ethyl stearate about the long axis of the cell. The spots previously observed on oscillation photographs of multilayers of ethyl stearate are in reality parts of circles, successive arcs of which appear on increasing the angle of incidence of the X -rays on the multilayer. These facts reveal that the multilayer consists of microcrystals all oriented with one axis in common, this axis being the normal to the surface of the multilayer. The single crystals appear to have grown without interruption throughout the entire thickness of the multilayer, which in these investigations was about 1000 mol. thick.

scholarly journals On the stability of unimolecular films. Part II.-The mechanism of film expansion

1929 ◽  
Vol 124 (794) ◽  
pp. 333-343 ◽  
Keyword(s):  
Aqueous Solution ◽  
Condensed State ◽  
Head Group ◽  
Chain Molecules ◽  
X Ray ◽  
Characteristic Area ◽  
The Stability ◽  
Contraction And Expansion ◽  
Long Chain ◽  
Hydrion Concentration

In Part I it was shown that the adhesion of a unimolecular film of a fatty acid to an underlying aqueous solution could be varied by alteration of the Hydrion concentration of the solution. Increasing the alkalinity effected an increase in the adhesional force of the polar beads, and under isothermal con­ditions a film could be converted from the expanded to the liquid condensed and even to the solid condensed state, by causing an increase in these adhesional forces, this process being perfectly reversible. Whilst ionisation of the acid occurs over a bruited range of P H , the alteration in adhesional forces by a change in P H and the effects of such change on the state of the film extend, contrary to the conclusions of Egner and Hägg,* over a much wider range of P H . Since contraction and expansion of the film coincide with an increase decrease respectively in the adhesional forces holding the polar heads to the surface, we may inter that expansion is effected by a gradual tilting of the molecules from the close packed formation existing in the solid condensed state. We have noted that Müller* from X-ray determinations on crystals of fatty acids suggested that it seemed possible that even in a film in the solid condensed state the molecules were already tilted. Objections to this view were raised by Adam, since he found but one characteristic area for long chain molecules in the solid condensed state, which was, with few exceptions, independent of the nature of the head group. He further found that the area in the liquid condensed state*was dependent on the nature of the head group.

scholarly journals The structure of polychloroprene

1942 ◽  
Vol 180 (980) ◽  
pp. 100-107 ◽  
Keyword(s):  
Physical Properties ◽  
Crystalline Structure ◽  
Light Treatment ◽  
Unit Cell ◽  
Cross Linking ◽  
Chain Molecules ◽  
X Ray ◽  
Before And After ◽  
Ray Methods ◽  
Long Chain

Specimens of polychloroprene before and after light treatment have been examined by X -ray methods. There is no change in the crystalline structure, although there are differences in the physical properties ascribed to cross-linking of the long-chain molecules. The unit cell is possibly ortho­rhombic: a = 8·90 A , b = 4·70 A, c = 12·21 A, and contains four chloroprene (C 4 H 5 Cl) units.

The Degree of Crystallinity in Natural Rubber. III. Correlation between X-Ray and Density Measurements

1950 ◽  
Vol 23 (2) ◽  
pp. 306-310 ◽  
Author(s):  
J. J. Arlman
Keyword(s):  
Natural Rubber ◽  
Unit Cell ◽  
Degree Of Crystallinity ◽  
X Rays ◽  
Density Measurements ◽  
X Ray ◽  
Degree Of Crystallization ◽  
The Degree Of Crystallinity

Abstract In 1925 Katz discovered the crystallization of stretched rubber. In the following years several investigators tried to determine the structure of rubber crystallites. The densities of the rubber crystallites calculated from the results of these investigations varied strongly. The results of x-ray and density measurements on crude rubber carried out by the author can be made to correspond only when the latter are based on the unit cell of Bunn. It is shown by experiment that, to measure the correct degree of crystallization, it is necessary to use monochromatic x-rays.

scholarly journals Structures of Multilayered Thin Films of Long-Chain Molecules: X-ray Scattering Study

2008 ◽  
Vol 40 (10) ◽  
pp. 1017-1024 ◽  
Author(s):  
Ken Tanaka ◽  
Kiyoshi Ishikawa ◽  
Koji Nozaki ◽  
Naohito Urakami ◽  
Takashi Yamamoto
Keyword(s):  
Thin Films ◽  
Chain Molecules ◽  
X Ray ◽  
X Ray Scattering ◽  
Scattering Study ◽  
Multilayered Thin Films ◽  
Long Chain ◽  
Ray Scattering

An X-Ray Investigation of Crystallinity in Rubber

1939 ◽  
Vol 12 (4) ◽  
pp. 706-718
Author(s):  
S. D. Gehman ◽  
J. E. Field
Keyword(s):  
Crystalline Structure ◽  
Polymeric Materials ◽  
The Other ◽  
X Ray Diffraction ◽  
Random Orientation ◽  
Chain Molecules ◽  
Micellar Structure ◽  
X Ray ◽  
Recent Developments ◽  
Long Chain

Abstract The crystalline structure which rubber exhibits under certain circumstances has come to be regarded as associated with a secondary or micellar structure of long chain molecules. The exact mechanism by which the localized ordered regions appear is a speculative subject in recent developments of the micellar theory of long chain polymeric materials. The views of various workers on this subject have been summarized by other authors. The crystalline structure of rubber displays varying degrees and types of orientation of the crystal units, depending on the conditions under which crystallization occurs. The amorphous x-ray diffraction pattern of unstretched rubber is shown in Figure 1, the unoriented crystalline diagram for frozen rubber in Figure 2. When crystallization is induced by stretching, the crystallites are aligned along the axis of stretching, giving the fiber diagrams of Figures 3 and 4. In this case there is random orientation of the other two axes of the crystallites. “Higher orientation,” in which all three axes of the crystallites are aligned, gives the diagram of Figure 15 and can be secured with suitable dimensions of the stretched piece.

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