Analysis of Cured, Filled Elastomeric Compounds by 13C NMR

Abstract This paper has discussed the study of cured, filled elastomers by a newly developed 13C NMR method. This method overcomes many of the shortcomings of other methods in that the 13C method is capable of distinguishing nonstandard or experimental polymeric components in an elastomeric blend, a definite advantage for the analyst. Other advantages are that the 13C data are primary, i.e., compositional calibration standards are not necessary once a polymer's 13C carbon resonances have been assigned; the data are accurate and reproducible; the filler (carbon black, TiO2, glass fibers) does not have to be removed prior to the analysis; and, the method is sensitive to low levels of polymer concentration. The superiority of 13C quantitative data over IR data has been demonstrated. Practical examples including nonstandard and/or unique elastomeric components have been discussed.

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One-Dimensional 13C NMR Is a Simple and Highly Quantitative Method for Enantiodiscrimination

Molecules ◽

10.3390/molecules23071785 ◽

2018 ◽

Vol 23 (7) ◽

pp. 1785 ◽

Cited By ~ 5

Author(s):

Peter Lankhorst ◽

Jozef van Rijn ◽

Alexander Duchateau

Keyword(s):

1H Nmr ◽

13C Nmr ◽

Quantitative Method ◽

Enantiomeric Excess ◽

Nmr Spectrum ◽

One Dimensional ◽

Nmr Method ◽

Relative Standard ◽

Excess Value ◽

Chiral Solvating Agent

The discrimination of enantiomers of mandelonitrile by means of 1D 13C NMR and with the aid of the chiral solvating agent (S)-(+)-1-(9-anthryl)-2,2,2-trifluoroethanol (TFAE) is presented. 1H NMR fails for this specific compound because proton signals either overlap with the signals of the chiral solvating agent or do not show separation between the (S)-enantiomer and the (R)-enantiomer. The 13C NMR method is validated by preparing artificial mixtures of the (R)-enantiomer and the racemate, and it is shown that with only 4 mg of mandelonitrile a detection limit of the minor enantiomer of 0.5% is obtained, corresponding to an enantiomeric excess value of 99%. Furthermore, the method shows high linearity, and has a small relative standard deviation of only 0.3% for the minor enantiomer when the relative abundance of this enantiomer is 20%. Therefore, the 13C NMR method is highly suitable for quantitative enantiodiscrimination. It is discussed that 13C NMR is preferred over 1H NMR in many situations, not only in molecules with more than one chiral center, resulting in complex mixtures of many stereoisomers, but also in the case of molecules with overlapping multiplets in the 1H NMR spectrum, and in the case of molecules with many quaternary carbon atoms, and therefore less abundant protons.

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Development of Ion Speciation Plots for Three Promising Tertiary Amine–CO2–H2O Systems Using the pH Method and the 13C NMR Method

Energy & Fuels ◽

10.1021/acs.energyfuels.6b03320 ◽

2017 ◽

Vol 31 (3) ◽

pp. 3069-3080 ◽

Cited By ~ 3

Author(s):

Moxia Li ◽

Helei Liu ◽

Xiao Luo ◽

Paitoon Tontiwachwuthikul ◽

Zhiwu Liang

Keyword(s):

Tertiary Amine ◽

13C Nmr ◽

Nmr Method

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Political Authority and University Formation in Europe, 1200–1800

Sociological Perspectives ◽

10.2307/1389441 ◽

1993 ◽

Vol 36 (1) ◽

pp. 45-62 ◽

Cited By ~ 28

Author(s):

Phyllis Riddle

Keyword(s):

Quantitative Data ◽

Historical Analysis ◽

Political Authority ◽

Institutional Perspective ◽

Western History ◽

Organizational Pattern ◽

Low Levels ◽

Bureaucratic State ◽

And Control ◽

The Relationship

Both historical analysis and data on university formation in Europe for the period 1200–1800 are used to introduce a perspective which links the organizational pattern of university foundings with the structure of political authority. Most theories of higher education cannot account for the pattern of university foundings. My political-institutional perspective interprets this pattern in the context of the relationship between knowledge and authority in Western history and connects the founding and control of a university to claims to political authority. Quantitative data suggest that universities are founded least where there is a central authority with relatively low levels of competing authority claims (e.g., England). They are founded most in highly decentralized regions characterized by many claims to sovereignty (e.g., Germany, Italy). Intermediate to high rates of foundings occur where a multiplicity of local and provincial claims to authority exist within a bureaucratic state (e.g., France, Spain).

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13C-NMR method for the study of the distribution of monomer units in copolyesters

Polymer Science U S S R ◽

10.1016/0032-3950(77)90079-x ◽

1977 ◽

Vol 19 (2) ◽

pp. 346-357 ◽

Cited By ~ 6

Author(s):

Ya.G. Urman ◽

S.G. Alekseyeva ◽

I.Ya. Slonim

Keyword(s):

13C Nmr ◽

Nmr Method

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Structure and Molecular Motion of Poly(ethylene oxide) Chains Tethered on Silica by Solid-State 13C NMR Method

Polymer Journal ◽

10.1295/polymj.33.584 ◽

2001 ◽

Vol 33 (8) ◽

pp. 584-589 ◽

Cited By ~ 10

Author(s):

Katsuhiro Yamamoto ◽

Atsushi Maruta ◽

Shigetaka Shimada

Keyword(s):

Solid State ◽

Ethylene Oxide ◽

13C Nmr ◽

Molecular Motion ◽

Nmr Method ◽

Poly Ethylene Oxide ◽

Poly Ethylene ◽

Solid State 13C Nmr

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Study of polyether thermoelastoplasts by the 1H and 13C NMR method

Polymer Science U S S R ◽

10.1016/0032-3950(82)90273-8 ◽

1982 ◽

Vol 24 (9) ◽

pp. 2149-2160 ◽

Cited By ~ 4

Author(s):

A.Kh. Bulai ◽

Ya.G. Urman ◽

F.M. Medvedeva ◽

I.Ya. Slonim ◽

L.D. Pin

Keyword(s):

13C Nmr ◽

1H And 13C Nmr ◽

Nmr Method

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Nutrition counselling and knowledge on iron and folic acid supplementation among pregnant women in Nyeri County, Kenya

International Journal of Community Medicine and Public Health ◽

10.18203/2394-6040.ijcmph20211209 ◽

2021 ◽

Vol 8 (4) ◽

pp. 1620

Author(s):

Henry Mburu Ng'the ◽

Douglas Nderitu ◽

Stephanie Wanja

Keyword(s):

Folic Acid ◽

Pregnant Women ◽

Quantitative Data ◽

Folic Acid Supplementation ◽

Acid Supplementation ◽

Focused Antenatal Care ◽

Folic Acid Supplements ◽

Iron And Folic Acid ◽

Low Levels ◽

The Government

Background: In the world, a deficiency of iron is the most common nutrition disorder affecting more than 30% of the global populace more so children and women. Countries in the developing world are working in programs on implementing the iron and folic acid supplementation (IFAS) although the effectiveness of curbing anemia is usually affected by non-compliance to iron and folic acid supplements by women who are pregnant. The government of Kenya has come up with strategies to deal with anemia which include supplementation of iron and folic acid, implementation of focused antenatal care even though they have encountered a few hurdles resulting to sub optimal coverage and low levels of compliance.Methods: This was a mixed method study whereby both qualitative and quantitative data was analysed. A sample size of 385 pregnant women were interviewed. Data was collected using questionnaires. Descriptive statistics were used to analyze the quantitative data which was presented in form of frequency and percentage tables, bar graphs and pie charts. Results: Results show that 96% of the expectant women indicated that they were advised to take fruits while 86% indicated that they were advised to take green vegetables. This shows that pregnant women in the study had good knowledge of their dietary needs.Conclusions: The study concludes that expectant women had high nutrition knowledge on foods that raise the haemoglobin levels during gravidity.

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