scholarly journals Molecular Weights and Physical Properties of Deoxyribonucleic Acid

Nature ◽  
1957 ◽  
Vol 180 (4598) ◽  
pp. 1340-1340 ◽  
Author(s):  
J. A. V. BUTLER ◽  
D. J. R. LAURENCE ◽  
A. B. ROBINS ◽  
K. V. SHOOTER
Keyword(s):  
Physical Properties ◽  
Deoxyribonucleic Acid ◽  
Molecular Weights

Relation between Molecular Weights and Physical Properties of Rubber Fractions

1941 ◽  
Vol 14 (3) ◽  
pp. 580-589 ◽  
Author(s):  
G. Gee ◽  
L. R. G. Treloar
Keyword(s):  
Molecular Weight ◽  
Natural Rubber ◽  
Physical Properties ◽  
High Molecular Weight ◽  
Elastic Properties ◽  
Elastic Material ◽  
Experimental Results ◽  
Molecular Weights ◽  
High Elasticity ◽  
Latex Rubber

Abstract As high elasticity is a property possessed only by substances of high molecular weight, it is of interest to enquire into the relation between the elastic properties of a highly elastic material such as rubber and its molecular weight. An investigation on these lines has been made possible through the work of Bloomfield and Farmer, who have succeeded in separating natural rubber into fractions having different average molecular weights. The more important physical properties of these fractions have been examined with the object of determining which of the properties are dependent on molecular weight and which are not. Fairly extensive observations were made on the fractions from latex rubber referred to as Nos. 2, 3 and 4 by Bloomfield and Farmer, and some less extensive observations were carried out on the less oxygenated portion of fraction No. 1 obtained from crepe rubber (called hereafter 1b) . Before considering these experimental results, and their relation to the molecular weights of the fractions, it will be necessary to refer briefly to the methods used for the molecular-weight determinations, and to discuss the significance of the figures obtained.

Purification of deoxyribonucleic acid polymerase .delta. from calf thymus: partial characterization of physical properties

Biochemistry ◽  
1980 ◽  
Vol 19 (10) ◽  
pp. 2096-2101 ◽  
Author(s):  
Marietta Y. W. Tsang Lee ◽  
Cheng-Keat Tan ◽  
Antero G. So ◽  
Kathleen M. Downey
Keyword(s):  
Physical Properties ◽  
Deoxyribonucleic Acid ◽  
Partial Characterization ◽  
Calf Thymus

scholarly journals Ultrasonic Scission of Deoxyribonucleic Acid in Aqueous Solution I. Conditions for Sonication and Molecular Weights of Sonicated Samples

1986 ◽  
Vol 18 (1) ◽  
pp. 71-79 ◽  
Author(s):  
Kiyohiro Fukudome ◽  
Kiwamu Yamaoka ◽  
Kenichiro Nishikori ◽  
Takamichi Takahashi ◽  
Osamu Yamamoto
Keyword(s):  
Aqueous Solution ◽  
Deoxyribonucleic Acid ◽  
Molecular Weights

Synthesis and Properties of Uniform Polyisoprene Networks. I. Synthesis and Characterization of α,ω-Dihydroxy-Polyisoprene

1976 ◽  
Vol 49 (2) ◽  
pp. 303-319 ◽  
Author(s):  
M. Morton ◽  
L. J. Fetters ◽  
J. Inomata ◽  
D. C. Rubio ◽  
R. N. Young
Keyword(s):  
Molecular Weight ◽  
Physical Properties ◽  
Soluble Fraction ◽  
Synthesis And Characterization ◽  
Molecular Weights ◽  
Molecular Weight Distributions ◽  
Weight Distributions ◽  
The Subject

Abstract The results of this study are the first to show that high-1,4 linear α,ω-dihydroxypolydienes can be synthesized with (a) predictable molecular weights, (b) narrow molecular weight distributions, and (c) high functionalities. Using the functionalized polyisoprenes prepared in this work, a series of networks was prepared with a purified triisocyanate as the chain linking agent. The soluble fraction in these networks ranged from 4.6 to 1.6 per cent. The characteristics and physical properties of these networks will be the subject of a forthcoming publication.

IV. The Micellar Theory of the Structure of Rubber

1942 ◽  
Vol 15 (3) ◽  
pp. 446-451
Author(s):  
G. Gee
Keyword(s):  
Molecular Weight ◽  
Physical Properties ◽  
Infinite Dilution ◽  
Mechanical Deformation ◽  
Point Of View ◽  
Pressure Measurements ◽  
Physical Behavior ◽  
Molecular Weights ◽  
Micelle Size ◽  
Weight Data

Abstract The molecular weight data reported in Part II depend on the assumption that the values obtained by extrapolating osmotic pressure measurements to infinite dilution represent true molecular weights. This point of view has been strongly criticized, particularly by Pummerer and his coworkers, according to whom rubber normally exists in solution in the form of micelles comprising more or less well-defined aggregates containing a considerable number of chemical molecules. The- osmotic “molecular weight” is then regarded as the weight of an average micelle. If they exist, these micelles may be important in determining both the chemical and physical behavior of rubber, for we should clearly expect the bonds by which the chemical molecules are bound into micelles to be weaker than those within the molecules. It may be noted that it has been shown elsewhere that the physical properties of a series of rubber fractions are closely related to their osmotic and viscosity molecular weights. Since, according to the micellar theory, these fractions can differ only in micelle size, their mechanical behavior must, from this viewpoint, be determined by the size of the micelles, which must therefore remain intact during mechanical deformation of the rubber. It is the object of the present paper to examine in more detail the basis of the micellar theory, and especially to offer an interpretation of the results of the East method, on which Pummerer's arguments are mainly based.

Isoprene and Rubber. Part 44. Viscosity Measurements of Squalene and Hydrosqualene Solutions

1936 ◽  
Vol 9 (4) ◽  
pp. 573-578
Author(s):  
H. Staudinger ◽  
H. P. Mojen
Keyword(s):  
Physical Properties ◽  
General Relation ◽  
Basic Structure ◽  
Degree Of Polymerization ◽  
Specific Viscosity ◽  
Viscosity Measurements ◽  
Molecular Weights ◽  
Gutta Percha ◽  
Rubber Part

Abstract The physical properties of highly polymerized substances, which are composed of fiber molecules, depend on the lengths of the chains of these fiber molecules. Thus tensile strength, elasticity, tendency to swell in solvents, and above all viscosity, are dependent on the length of chain of the particular substance. Among the substances, the properties of which vary thus, are rubber, gutta-percha, and balata. Since the length of fiber molecules can vary within wide limits, such physical properties as those mentioned above show wide variations in the case of rubber, gutta-percha, and balata. This is evident for example by a comparison of the properties of unmasticated rubber, which consists of long fiber molecules of a degree of polymerization of 2000, with the properties of masticated rubber, the greatly dissociated molecules of which have a degree of polymerization of only 500. The determination of the length of the fiber molecules is therefore of great importance in the case of highly polymerized substances. It has already been proved in past experiments with members of a series of homologous polymers, i. e., of substances the macromolecules of which have the same basic structure and differ only in length, that the molecular weights can be determined from viscosity measurements. This determination is based on the fact that there is a general relation between the specific viscosity and the length of the dissolved molecules, which can be expressed by the formula:

Sign in / Sign up

Export Citation Format

Share Document