Spectrophotometric Determination of Sulfide End Groups and Number Average Molecular Weight in High Polymers

1960 ◽  
Vol 32 (12) ◽  
pp. 1713-1716 ◽  
Author(s):  
Isadore. Rosenthal ◽  
G. J. Frisone ◽  
J. K. Coberg
Keyword(s):  
Molecular Weight ◽  
Spectrophotometric Determination ◽  
Average Molecular Weight ◽  
Number Average Molecular Weight ◽  
End Groups ◽  
High Polymers

EBULLIOMETRY AND THE DETERMINATION OF THE MOLECULAR WEIGHTS OF POLYMERS: PART I. THE SMALL EBULLIOMETER

1959 ◽  
Vol 37 (9) ◽  
pp. 1508-1516 ◽  
Author(s):  
W. R. Blackmore
Keyword(s):  
Molecular Weight ◽  
Average Molecular Weight ◽  
Number Average Molecular Weight ◽  
Molecular Weights

An ebulliometer that has been in routine use for the determination of the number average molecular weight of polymers is described. The results obtained with two different series of polythenes (which were also measured elsewhere) are given. These results show this ebulliometer to be subject to experimental difficulties which limit it to number average molecular weights of perhaps 20,000 depending on the precision required.

The Absolute, Entirely Viscometric Determination of the Molecular Weight of high Polymers

1957 ◽  
Vol 30 (2) ◽  
pp. 470-486 ◽  
Author(s):  
K. Edelmann
Keyword(s):  
Molecular Weight ◽  
Average Molecular Weight ◽  
Absolute Value ◽  
Simple Measurement ◽  
The Absolute ◽  
Viscosity Determination ◽  
Numerical Knowledge ◽  
High Polymers

Abstract The utility of high polymers in all fields of application depends on the average molecular weight. In general, strength, elasticity and tear resistance under sudden stress increase with the molecular weight. On the contrary, processibility and solubility decrease with increasing molecular weight. The opposing requirements for quality and economy lead to the necessity of possessing as accurate a knowledge of the molecular weight as possible, to make certain that the molecular weight of a product is adequate for the requirements of a definite application. Normally, a simple measurement of viscosity will suffice as a test for the characterization of a definite product. The knowledge of the absolute value of the molecular weight is not required in the case where it is possible to arrange different samples in a correct series. However, in many cases a numerical knowledge of the molecular weight is desirable. In the case of the reactions of cellulose, e.g., it is often necessary to determine at what point decomposition occurs. Normally, this is not possible by means of a simple viscosity determination, since its standardization against absolute methods varies with the degree of substitution and the type of solvent. To this must be added, the causes for the occurrence of structural viscosity in solutions of linear macromolecules, which also make it necessary to determine the molecular weight for the evaluation of these high polymers.

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