Effect of the Cyclopentadienyl Fragment on Monomer Reactivities and Monomer Sequence Distributions in Ethylene/α-Olefin Copolymerization by a Nonbridged (Cyclopentadienyl)(aryloxy)titanium(IV) Complex−MAO Catalyst System

2000 ◽  
Vol 33 (9) ◽  
pp. 3187-3189 ◽  
Author(s):  
Kotohiro Nomura ◽  
Keima Oya ◽  
Takashi Komatsu ◽  
Yukio Imanishi
Keyword(s):  
Catalyst System ◽  
Monomer Sequence ◽  
Sequence Distributions

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.

Facile Method of Controlling Monomer Sequence Distributions in Random Copolymers

2007 ◽  
Vol 19 (19) ◽  
pp. 2877-2883 ◽  
Author(s):  
J. J. Semler ◽  
Y. K. Jhon ◽  
A. Tonelli ◽  
M. Beevers ◽  
R. Krishnamoorti ◽  
...  
Keyword(s):  
Random Copolymers ◽  
Monomer Sequence ◽  
Sequence Distributions

Monomer sequence distributions in ethylene-1-hexene copolymers

1982 ◽  
Vol 15 (5) ◽  
pp. 1402-1406 ◽  
Author(s):  
Eric T. Hsieh ◽  
James C. Randall
Keyword(s):  
Monomer Sequence ◽  
Sequence Distributions

scholarly journals Patterning Polyelectrolyte Complexes with Alternating Monomer Sequence Distributions

2019 ◽  
Author(s):  
Abraham Herzog-Arbeitman ◽  
Jeffrey Ting ◽  
Siqi Meng ◽  
Hao Wu ◽  
Matthew Tirrell
Keyword(s):  
Phase Separation ◽  
Polyelectrolyte Complexes ◽  
Monomer Sequence ◽  
Charged Macromolecules ◽  
Chain Sequence ◽  
Sequence Distributions

<div> <div> <div> <p>Charge-driven complexation of polyelectrolytes in water is a fundamental phase separation phenomenon that is prevalent in nature and across the high-value technology landscape. Here we describe an experimentally convenient and versatile approach to construct patterned PECs, comprising well-defined charged macromolecules with both ionic styrene and neutral maleimide units alternating in the chain sequence. </p> </div> </div> </div>

Estimating Monomer Sequence Distributions in Tetrapolyacrylates

2014 ◽  
Vol 48 (1) ◽  
pp. 58-63 ◽  
Author(s):  
Yavuz Caydamli ◽  
Yi Ding ◽  
Abhay Joijode ◽  
Shanshan Li ◽  
Jialong Shen ◽  
...  
Keyword(s):  
Monomer Sequence ◽  
Sequence Distributions

Monomer sequence distributions in four-component polyesters as determined by carbon-13 and hydrogen-1 NMR

1981 ◽  
Vol 14 (6) ◽  
pp. 1764-1770 ◽  
Author(s):  
G. A. Russell ◽  
P. M. Henrichs ◽  
J. M. Hewitt ◽  
H. R. Grashof ◽  
M. A. Sandhu
Keyword(s):  
Monomer Sequence ◽  
Sequence Distributions

Infrared Determination of Composition of Ethylene-Propylene Copolymers

1971 ◽  
Vol 44 (4) ◽  
pp. 1015-1024 ◽  
Author(s):  
I. J. Gardner ◽  
C. Cozewith ◽  
G. Ver Strate
Keyword(s):  
Isotope Effects ◽  
Catalyst System ◽  
Nmr Analysis ◽  
Atactic Polypropylene ◽  
Ethylene Propylene ◽  
Carbon 14 ◽  
Sample Composition ◽  
System Solution ◽  
Sequence Distributions

Abstract Carbon-14 labeled ethylene and propylene were used to synthesize a series of copolymers of known composition to serve as standards for copolymer analyses. Polymers with broad and narrow compositional distributions and differing sequence distributions were produced by varying the catalyst system. Solution and combustion counting techniques were used to determine sample composition and then infrared calibration curves were determined on pressed polymer films utilizing several different infrared peaks. 1. Within the ranges systematically varied neither compositional nor sequence distributions affect the peak ratios studied. 2. No isotope effects exist in the polymerizations. 3. NMR analysis yields the same results as 14C analysis. 4. Use of the 1378 cm−1 methyl band as calibrated with atactic polypropylene yields agreement with the 14C data if the average of polypropylene and copolymer results is used. 5. We amend the results previously published by our laboratory.

Monomer sequence distributions in the copolymerization of ethylene and 1-decene

1994 ◽  
Vol 195 (7) ◽  
pp. 2457-2467 ◽  
Author(s):  
Begoña Peña ◽  
Juan A. Delgado ◽  
Ernesto Pérez ◽  
Antonio Bello
Keyword(s):  
Monomer Sequence ◽  
Sequence Distributions

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.

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