ELECTRIC MOMENT AND MOLECULAR STRUCTURE. VIII. COMPLEX DIPOLES AND LONG-CHAIN MOLECULES

1932 ◽  
Vol 54 (6) ◽  
pp. 2261-2270 ◽  
Author(s):  
C. P. Smyth ◽  
W. S. Walls
Keyword(s):  
Molecular Structure ◽  
Electric Moment ◽  
Chain Molecules ◽  
Long Chain

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.

Observations on the X-Ray Structure of Rubber and the Size and Shape of Rubber Crystallites

1944 ◽  
Vol 17 (3) ◽  
pp. 640-652
Author(s):  
S. D. Gehman ◽  
J. E. Field
Keyword(s):  
Molecular Structure ◽  
Physical Properties ◽  
X Ray Diffraction ◽  
Ray Method ◽  
Chain Molecules ◽  
X Ray ◽  
Rubberlike Material ◽  
Molecular Forces ◽  
Ray Patterns ◽  
Long Chain

Abstract In former times, we used to be painfully aware of the shortcomings and elastic imperfections of Hevea rubber. With its disappearance, we have come to think of it as having an ideal balance in physical properties for a rubberlike material which it has been difficult to approach with synthetic polymers. for this reason, it is still important to investigate the molecular structure of Hevea rubber and to try to understand the characteristics of this structure which are responsible for its physical properties. X-Ray diffraction methods can be applied to the problem of the molecular structure of Hevea rubber and a few synthetic rubbers, such as Butyl rubber and Neoprene, because crystallization occurs upon stretching. A detailed description of the x-ray diffraction results with rubber is available in a review article and need not be repeated here. It should be pointed out that the story obtained from the x-ray structure is not complete because there are important aspects of the structure which are not revealed by this means. It is not possible to measure directly the length of the chain molecules. The nature of the amorphous phase, such as the system of cross-linking of the long chain molecules on vulcanization, does not become evident in x-ray patterns. The physical properties of Hevea rubber must depend on a delicate balance of primary and secondary valence forces. The x-ray method does not permit any direct measurement of these forces but merely shows the geometrical arrangement which results from the molecular forces. Even with these limitations, much valuable information can be secured on the nature of the molecular rearrangements which occur upon stretching. Deductions can be drawn from the x-ray diffraction results regarding the form and spatial relationships of the long chain polymeric molecules and the manner in which they interact under stress. Correlations can then be looked for between the crystallization and the physical properties.

scholarly journals The Excluded Volume Effect of Very-long-chain Molecules

1968 ◽  
Vol 41 (2) ◽  
pp. 538-538 ◽  
Author(s):  
Keizo Suzuki
Keyword(s):  
Volume Effect ◽  
Excluded Volume ◽  
Chain Molecules ◽  
Excluded Volume Effect ◽  
Long Chain

Velocity autocorrelation function for the motion of long-chain molecules in the free draining limit

1973 ◽  
Vol 8 (4) ◽  
pp. 367-371
Author(s):  
B. Caroli ◽  
G. Jannink ◽  
D. Saint-James ◽  
D. Taupin
Keyword(s):  
Autocorrelation Function ◽  
Velocity Autocorrelation Function ◽  
Chain Molecules ◽  
Velocity Autocorrelation ◽  
Long Chain

ELECTRIC MOMENT AND MOLECULAR STRUCTURE. IX. THE OXYGEN AND SULFUR VALENCE ANGLES

1932 ◽  
Vol 54 (8) ◽  
pp. 3230-3240 ◽  
Author(s):  
C. P. Smyth ◽  
W. S. Walls
Keyword(s):  
Molecular Structure ◽  
Electric Moment

Effect of density on configurational properties of long-chain molecules using a Monte Carlo method

1966 ◽  
Vol 62 ◽  
pp. 3319 ◽  
Author(s):  
S. G. Whittington ◽  
D. Chapman
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Chain Molecules ◽  
Long Chain

Conformational transitions of long chain molecules in frozen solutions

1989 ◽  
Vol 91 (11) ◽  
pp. 7296-7299 ◽  
Author(s):  
R. Hirschmann ◽  
J. Friedrich ◽  
E. Daltrozzo
Keyword(s):  
Conformational Transitions ◽  
Chain Molecules ◽  
Frozen Solutions ◽  
Long Chain

Theory of Depolymerization of Long Chain Molecules

1940 ◽  
Vol 8 (9) ◽  
pp. 721-726 ◽  
Author(s):  
Elliott W. Montroll ◽  
Robert Simha
Keyword(s):  
Chain Molecules ◽  
Long Chain
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