A Facile Procedure for Controlling Monomer Sequence Distribution in Radical Chain Polymerizations

2007 ◽  
Vol 129 (31) ◽  
pp. 9542-9543 ◽  
Author(s):  
Sebastian Pfeifer ◽  
Jean-François Lutz
Keyword(s):  
Radical Chain ◽  
Sequence Distribution ◽  
Monomer Sequence

Monomer Sequence Distribution in Butadiene Styrene Copolymers

1970 ◽  
Vol 43 (5) ◽  
pp. 1138-1153 ◽  
Author(s):  
V. D. Mochel ◽  
B. L. Johnson
Keyword(s):  
Aromatic Proton ◽  
Analog Computer ◽  
Curve Analysis ◽  
Nmr Spectrum ◽  
Sequence Distribution ◽  
Monomer Sequence ◽  
Styrene Copolymers ◽  
Overlapped Peaks ◽  
Sequence Distributions ◽  
Butadiene Styrene

Abstract A method is described for determining styrene sequence distribution in butadiene-styrene copolymers. An analog computer is used to resolve overlapped peaks in the styrene aromatic proton NMR spectrum. In n-BuLi copolymers a quite quantitative distinction can be made between “short” sequences, containing two and three styrene units, and “long” sequences, containing more than three units. With this method it is possible to determine experimentally the styrene-centered triad distributions and approximate styrene sequence distributions of butadiene—styrene copolymers. Agreement between calculated and NMR-curve analysis results is good, especially for n-butyllithium-catalyzed butadiene—styrene copolymers.

Determining the Polydispersity in Chemical Composition and Monomer Sequence Distribution in Random Copolymers Prepared by Postpolymerization Modification of Homopolymers

2012 ◽  
Vol 1 (9) ◽  
pp. 1128-1133 ◽  
Author(s):  
Wayne Powers ◽  
Chang Y. Ryu ◽  
Young K. Jhon ◽  
Lawrence A. Strickland ◽  
Carol K. Hall ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Random Copolymers ◽  
Sequence Distribution ◽  
Monomer Sequence

Thermoelasticity and Stress Induced Crystallization of EPDM Elastomers

1971 ◽  
Vol 44 (4) ◽  
pp. 1093-1108 ◽  
Author(s):  
U. Flisi ◽  
A. Valvassori ◽  
G. Novajra
Keyword(s):  
Thermodynamic Properties ◽  
Composition Range ◽  
Amorphous Polymers ◽  
Microstructural Parameter ◽  
Sequence Distribution ◽  
Monomer Sequence ◽  
Stretching Ratio ◽  
Narrow Composition Range ◽  
Stress Induced Crystallization ◽  
Induced Crystallization

Abstract The thermoelastic behavior of various EPDM rubbers has been investigated by performing stress-temperature measurements at different stretching ratios in order to determine their thermodynamic properties and the occurrence of stress induced crystallization. A broad range of terpolymer compositions was investigated and the regularity of monomer sequence distribution was also taken into account. It has been found that statistical terpolymers, like the commercial ones, are generally amorphous and hardly crystallize under stretching for propylene contents higher than 40% by weight. Below this level it is possible to obtain, in a narrow composition range, amorphous polymers that can crystallize under stretching, provided that their monomer sequence distribution is regular enough. The influence of this microstructural parameter has been studied by testing a 3/1 ethylene/propylene model copolymer, obtained by hydrogenation of a sample of poly-3-methyloctenamer. Studying the influence of stretching ratio on crystallization temperature of standard EPDM rubbers, it has been noticed that crystallization occurs at low elongation, which might be related to the presence of “nuclei” in the undeformed state.

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