13C NMR Characterization of Polychloroprene Microstructure II. Relaxation, NOE, and Quantitative Measurements

1978 ◽  
Vol 51 (4) ◽  
pp. 668-676 ◽  
Author(s):  
M. M. Coleman ◽  
E. G. Brame
Keyword(s):  
Free Radical ◽  
Spin Relaxation ◽  
13C Nmr ◽  
Quantitative Measurements ◽  
Nmr Characterization ◽  
Infrared Studies ◽  
Excellent Method ◽  
Quantitative Results ◽  
Structural Irregularities

Abstract Spin relaxation, NOE, and quantitative measurements have been performed on chloroprene polymers prepared by free radical techniques in the range −150 to +90°C. 13C NMR has proved to be an excellent method for the characterization of polychloroprene microstructure. From our quantitative results it would appear that the concentration of cis-1,4 structural irregularities has been considerably overestimated in previous infrared studies. In addition, the relative amount of trans-1,4 inversions (HT) appears to be somewhat higher than previously reported.

13C NMR Characterization of Copolymers Of 2-Chlorobutadiene-1,3 and 2,3-Dichlorobutadiene-1,3

1977 ◽  
Vol 50 (2) ◽  
pp. 272-277 ◽  
Author(s):  
E. G. Brame ◽  
A. A. Khan
Keyword(s):  
Free Radical ◽  
13C Nmr ◽  
Experimental Studies ◽  
Propagation Rate ◽  
Vinyl Monomers ◽  
1H And 13C Nmr ◽  
Polymer Properties ◽  
Nmr Characterization ◽  
Emulsion Systems

Abstract Due to the facile free-radical polymerization of 2-chlorobutadiene-1,3 (chloroprene, CB), most experimental studies and commercial polymer preparations involve free-radical-initiated emulsion systems. From the reactivity ratios published in the literature and the calculated propagation rate of CB at 40°C, its rate is about 10 times faster than that of butadiene. Uniquely, among all the vinyl and diene monomers known, 2,3-dichlorobutadiene-1,3 (DCB) is more reactive than CB. Modification of the properties of polyCB through copolymerization is often relatively difficult. The comonomer most frequently used with CB is DCB, even though many other dienes and vinyl monomers have been tested. Copolymerization of DCB with CB modifies the polymer properties, as judged by evidence from increased crystallization resistance and the retention of building tack. The effect of DCB on the properties of the copolymer of CB and DCB is markedly influenced by the amount of comonomer present. Since no detailed studies have been reported on this monomer pair, we report here microstructure analyses by both 1H and 13C NMR on CB-DCB copolymers. However, it was the 18C NMR analyses which provided the major characterization of these copolymers, while the 1H NMR was only used for the analysis of their composition.

13C NMR Characterization of Polychloroprene Microstructure I. Spectral Assignments

1977 ◽  
Vol 50 (1) ◽  
pp. 49-62 ◽  
Author(s):  
M. M. Coleman ◽  
D. L. Tabb ◽  
E. G. Brame
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
Quantitative Data ◽  
Nmr Relaxation ◽  
13C Nmr Spectroscopy ◽  
Nmr Characterization ◽  
Relaxation Studies ◽  
Structural Irregularities ◽  
Near Future

Abstract 13C NMR spectroscopy has proved to be a very powerful tool for the characterization of polychloroprene microstructure. We have identified and assigned the lines associated with diad and triad sequences involving the predominant trans-1,4 placement, together with other lines associated with cis-1,4, 1,2, isomerized 1,2, and 3,4 structural irregularities. Currently, we are performing 13C NMR, relaxation studies on the chloroprene polymers and will be presenting quantitative data in the near future.

1H NMR and 13C NMR characterization of n-heptane extraction of low-temperature coal tar reacted with formaldehyde

2019 ◽  
Vol 42 (12) ◽  
pp. 1490-1498
Author(s):  
Qiuxiang Yao ◽  
Xiangxi Kong ◽  
Xiaomin Dai ◽  
Junwen Gao ◽  
Rucheng Wang ◽  
...  
Keyword(s):  
Low Temperature ◽  
1H Nmr ◽  
13C Nmr ◽  
Coal Tar ◽  
Nmr Characterization

13C NMR characterization of unsaturated terminal structures in oligoisobutylenes

1995 ◽  
Vol 34 (4) ◽  
pp. 461-467 ◽  
Author(s):  
Jiří Spěváček ◽  
Luděk Toman ◽  
Petr Vlěk
Keyword(s):  
13C Nmr ◽  
Nmr Characterization

Chromatographic separation and 13C NMR characterization of aromatic diester-diacids isomers

1996 ◽  
Vol 197 (4) ◽  
pp. 1473-1484 ◽  
Author(s):  
Wenxi Huang ◽  
Lianxun Gao ◽  
Xin Zhang ◽  
Jiping Xu ◽  
Mengxian Ding
Keyword(s):  
13C Nmr ◽  
Chromatographic Separation ◽  
Nmr Characterization

scholarly journals Quantitative 13C NMR characterization of fast pyrolysis oils

RSC Advances ◽  
2016 ◽  
Vol 6 (104) ◽  
pp. 102665-102670 ◽  
Author(s):  
R. M. Happs ◽  
K. Iisa ◽  
J. R. Ferrell III
Keyword(s):  
13C Nmr ◽  
Fast Pyrolysis ◽  
Nmr Characterization ◽  
Pyrolysis Oils ◽  
Dept Spectra

DEPT spectra illustrate the overlap of aromatic C–H signals in the aromatic C–C region for catalytic and hydrotreated pyrolysis oils.

Solid-state 13C NMR characterization of annealed poly (p-phenylene vinylene) PPV Films

1990 ◽  
Vol 28 (10) ◽  
pp. 1859-1869 ◽  
Author(s):  
Jeffrey H. Simpson ◽  
Norbert Egger ◽  
Michael A. Masse ◽  
David M. Rice ◽  
Frank E. Karasz
Keyword(s):  
Solid State ◽  
13C Nmr ◽  
Phenylene Vinylene ◽  
Nmr Characterization ◽  
Solid State 13C Nmr
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