Monomer sequence distribution in ethylene-propylene copolymers by computer analysis of infrared spectra

1968 ◽  
Vol 40 (2) ◽  
pp. 370-379 ◽  
Author(s):  
Harry V. Drushel ◽  
Julia S. Ellerbe ◽  
Robert C. Cox ◽  
Lloyd H. Lane
Keyword(s):  
Computer Analysis ◽  
Infrared Spectra ◽  
Sequence Distribution ◽  
Ethylene Propylene ◽  
Monomer Sequence

Monomer Sequence Distribution in Ethylene Propylene Elastomers. I. Measurement by Carbon-13 Nuclear Magnetic Resonance Spectroscopy

1971 ◽  
Vol 44 (3) ◽  
pp. 781-804 ◽  
Author(s):  
C. J. Carman ◽  
C. E. Wilkes
Keyword(s):  
Chemical Shifts ◽  
Catalyst System ◽  
Reactivity Ratio ◽  
Sequence Length ◽  
Copolymer Composition ◽  
Resonance Spectroscopy ◽  
Sequence Distribution ◽  
Ethylene Propylene ◽  
Average Value ◽  
Monomer Sequence

Abstract The carbon-13 chemical shifts of ethylene propylene copolymers were found to be very sensitive to monomer sequence distribution. Methylene resonances were interpreted in terms of methylene sequence length and tertiary carbon resonances were interpreted in terms of propylene centered pentad sequences. Propylene inversion was detected and measured quantitatively in the spectra. A formula was derived for calculating r1·r2, which is independent of monomer feed, and which is based on measuring contiguous and isolated propylene sequences in the copolymer. The interpretations are shown to be consistent for copolymers containing 26, 34, and 62 mole% propylene. The r1·r2 products were determined for each of these polymers. Calculation of copolymer composition based on the 13C chemical shift assignments gave excellent agreement with the compositions as determined by infrared and 1H NMR. A formula was derived, based on copolymerization theory, for calculating the reactivity ratio product, r1·r2, directly from the copolymer composition (% ethylene) and the ratio of contiguous to isolated propylene sequences. Using this formula an average value for r1·r2=0.42±0.02 was determined for the copolymers made with vanadium acetylacetonate-diethylaluminum chloride catalyst system.

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.

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