Cationic copolymers of isobutylene. 7. Reactivity ratio determination by sequence distributions obtained through NMR analysis

1984 ◽  
Vol 17 (1) ◽  
pp. 37-41 ◽  
Author(s):  
Carlo Corno ◽  
Aldo Priola ◽  
G. Spallanzani ◽  
Sebastiano Cesca
Keyword(s):  
Reactivity Ratio ◽  
Nmr Analysis ◽  
Ratio Determination ◽  
Cationic Copolymers ◽  
Sequence Distributions

NMR Composition Analysis of Copolymers

1967 ◽  
Vol 40 (4) ◽  
pp. 1200-1211 ◽  
Author(s):  
Virgil D. Mochel
Keyword(s):  
Double Resonance ◽  
Oxidative Degradation ◽  
Resonance Region ◽  
Accurate Method ◽  
Composition Analysis ◽  
Nmr Analysis ◽  
Structural Isomers ◽  
High Resolution Nmr ◽  
Sequence Distributions ◽  
Butadiene Styrene

Abstract High resolution NMR spectroscopy has been shown to be a most useful tool for elucidation of compositions and structures of polymers. It is a rapid, accurate method of analysis and requires no external calibration. This technique of composition analysis can be applied to any copolymer, terpolymer, or homopolymer with various structural isomers, provided a suitable number of resonance peaks can be unambiguously assigned to at least one proton of each of the structures present. Accuracy depends upon the relative isolation of these selected peaks. The method was applied to butadiene styrene and butadiene isoprene copolymers. Equations developed previously for both systems were extended and modified to give better accuracy. In the former copolymer the NMR analysis for block styrene agreed very well with the chemical oxidative degradation method over the range 0-20 per cent. It is believed that sequence lengths smaller than five styrene units can be observed as block styrene by NMR. It was also shown that there is a sequence distribution effect in the 1,2 addition butadiene olefinic resonance region of the spectrum. This effect is also observed in polybutadienes and in the butadiene isoprene copolymers. Further study of this might be fruitful. Accuracy of the NMR method was demonstrated in the butadiene isoprene case by study of four high conversion, emulsion copolymers and six blends of butadiene and isoprene homopolymers. In all samples except one the total isoprene content found by either the detailed NMR analysis or the much more simplified NMR analysis agreed within 2 per cent of that known to be present. Accuracy is greatest for those copolymers or blends which have relatively low 1,2 addition butadiene contents, such as with butyllithium-catalyzed polymers. Accuracy is poor when the copolymer or blend has an isoprene content less than 10 per cent along with a high 1,2 addition butadiene content. Composition analysis of copolymers by NMR will become increasingly important since it often provides a direct, simple fingerprint of the various structures. However, NMR will probably make its most significant contributions in stereochemical studies of tacticities, sequence distributions, and orientation, such as head-to-head or tail-to-tail linkages. In these problems deuteration techniques, double resonance techniques, and higher field strengths play an indispensable role.

Hydrophobically modified polyelectrolytes III. Reactivity ratio determination of FX14/AA, LA/AA and SA/AA

2010 ◽  
Vol 18 (4) ◽  
pp. 626-634
Author(s):  
Zhuang Dong-Qing ◽  
Shi Li-Ping ◽  
Yu Yi-Hua ◽  
Zhang Yun-Xiang
Keyword(s):  
Reactivity Ratio ◽  
Hydrophobically Modified ◽  
Ratio Determination

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.

scholarly journals NMR analysis and triad sequence distributions of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)

2020 ◽  
Vol 90 ◽  
pp. 106754
Author(s):  
H.N. Cheng ◽  
Atanu Biswas ◽  
Karl Vermillion ◽  
Beatriz Melendez-Rodriguez ◽  
Jose Maria Lagaron
Keyword(s):  
Nmr Analysis ◽  
Sequence Distributions

Copolymerization of novel reactive fluorinated acrylic monomers with styrene: reactivity ratio determination

2014 ◽  
Vol 292 (7) ◽  
pp. 1711-1717 ◽  
Author(s):  
Chahinez Benbayer ◽  
Salima Saidi-Besbes ◽  
Elisabeth Taffin de Givenchy ◽  
Sonia Amigoni ◽  
Frédéric Guittard ◽  
...  
Keyword(s):  
Reactivity Ratio ◽  
Acrylic Monomers ◽  
Ratio Determination

Reactivity Ratio of Emulsion Copolymerization of Fluorinated Gaseous Monomers-Vinylidene Fluoride and Hexafluoropropylene

2011 ◽  
Vol 183-185 ◽  
pp. 1591-1595 ◽  
Author(s):  
Zhong Xie ◽  
Qi Xin Zhuang ◽  
Xiao Yun Liu ◽  
Jun Qian ◽  
Zhe Wen Han
Keyword(s):  
Gas Chromatography ◽  
Vinylidene Fluoride ◽  
Reactivity Ratio ◽  
Reactivity Ratios ◽  
Nmr Analysis ◽  
Emulsion Copolymerization ◽  
Nonlinear Fitting ◽  
Before And After

The apparent reactivity ratios of hexafluoropropylene (HFP)/vinylidene fluoride (VDF) emulsion copolymerization were studied by nonlinear fitting according to the copolymer composing equation, which, according to the calculation, are 1.88 and 0.86 respectively. The constitution of mixed gaseous monomers was measured through the gas chromatography. The copolymer compositions before and after reaction were measured by 19F-NMR. The calculated contents of VDF and HFP have nice accordance with the results from 19F-NMR analysis, which demonstrates that the method reported here is fairly reliable, and shed a light on the industry-scale consideration for the emulsion copolymerization of HFP and VDF.

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