ZIB

Digitale Medien

Line broadening in the 13C NMR spectra of bulk polymers above Tg (1983)

Komoroski, Richard A.

New York : Wiley-Blackwell

Journal of Polymer Science: Polymer Physics Edition 21 (1983), S. 2551-2559

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 0098-1273

Schlagwort(e): Physics ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Physik

Notizen: The effects of magic-angle sample spinning (MAS), high-power decoupling, and resonance frequency on the 13C NMR linewidths of bulk polyisobutylene and bulk trans-polybutadiene are examined. The 13C linewidths increase with resonance frequency, are unaffected by high-power decoupling, and are reduced to different extents by MAS. The dominant contribution of the natural linewidth of the polyisobutylene lines is confirmed. The two carbons of trans-polybutadiene have approximately equal linewidths under all conditions, a result that eliminates residual chemical shift anisotropy as a major contributor to the linewidths. The large reduction of the trans-polybutadiene linewidths with MAS, coupled with the above result, suggests that microscopic variation of magnetic susceptibility is the major factor for this semicrystalline polymer. Cross-polarized 13C spectra of trans-polybutadiene were obtained with and without MAS. With MAS, resonances due to the crystalline and amorphous components were resolved. The principal components of the chemical shift tensor of the vinylene carbons were obtained from the spectrum without MAS.

Zusätzliches Material: 2 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/pol.1983.180211211

Permalink

Bibliothek	Standort	Signatur	Band/Heft/Jahr	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

Digitale Medien

13C-NMR sequence analysis of polyesters from pentaerythritol and caprolactone (1981)

Newmark, Richard A. ; Runge, Michael L. ; Chermack, Julie A.

New York : Wiley-Blackwell

Journal of Polymer Science: Polymer Chemistry Edition 19 (1981), S. 1329-1336

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 0360-6376

Schlagwort(e): Physics ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie

Notizen: Reaction of pentaerythritol (1) or dipentaerythritol with caprolactone yields prepolymers of the general structure \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm C} { \left( {\rm CH}_2 {\rm OH} \right)_4 } \hbox{--} {\rm i} \left [ {\rm CH}_2 {\rm O} \left( {\rm COCH}_2 {\rm CH}_2 {\rm CH}_2 {\rm CH}_2 {\rm CH}_2 {\rm O} \right)_{\rm n} {\rm H} \right]_{\rm i}$$\end{document} for i = 1, 2, 3, and 4 (2)-(5). The 13C chemical shifts of the quaternary carbons in (1)-(5) differ by more than 0.5 ppm. Conditions were determined to obtain quantitative intensity ratios of these carbons. The relative intensities give the distribution of the various branched structures and permit calculations of the average number of caprolactones per branch. Results are reported for caprolactone/polyol mole ratics of 3-66.

Zusätzliches Material: 2 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/pol.1981.170190605

Permalink

Bibliothek	Standort	Signatur	Band/Heft/Jahr	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

Digitale Medien

N-methyl-substituted aromatic polyamidesPaper presented in part at the 28th Southeastern Regional Meeting of the American Chemical Society, Gatlinburg, Tennessee, October 1976. (1980)

Greenwood, Thomas D. ; Kahley, Richard A. ; Wolfe, James F. ; [weitere]

New York : Wiley-Blackwell

Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 1047-1059

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 0360-6376

Schlagwort(e): Physics ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie

Notizen: A series of N-methyl-substituted aromatic polyamides derived from the secondary aromatic diamines 4,4′-bis(methylamino)diphenylmethane, 3,3′-bis(methylamino)diphenylmethane, 4,4′-bis(methylamino)benzophenone or 3,3′-bis(methylamino)benzophenone and isophthaloyl dichloride, and terephthaloyl dichloride or 3,3′-diphenylmethane dicarboxylic acid dichloride was prepared by high-temperature solution polymerization in s-tetrachloroethane. Compared with analogous unsubstituted and partly N-methylated aromatic polyamides, the full N-methylated polyamides exhibited significantly lower glass transition temperatures (Tg), reduced crystallinity, improved thermal stability, and good solubility in chlorinated solvents.

Zusätzliches Material: 3 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/pol.1980.170180323

Permalink

Bibliothek	Standort	Signatur	Band/Heft/Jahr	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

Digitale Medien

Sequence distribution in polyethylene/tetramethylene terephthalate copolyesters by 13C-NMR (1980)

Newmark, Richard A.

New York : Wiley-Blackwell

Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 559-563

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 0360-6376

Schlagwort(e): Physics ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie

Notizen: 13C-NMR gives sequence information in copolyesters synthesized from ethylene glycol (EG), 1,4-butane diol (BD), and methyl terephthalate (TP). The EG-TP-EG and BD-TP-BD blocks are distinguishable from the unsymmetrical diester sequence EG-TP-BD. The carbonyl and aromatic quaternary carbons of terephthalate have different chemical shifts but identical relaxation times and nuclear Overhauser enhancements in the three different triad sequences. Peak areas indicate random copolymerization of the three copolyesters studied.

Zusätzliches Material: 1 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/pol.1980.170180216

Permalink

Bibliothek	Standort	Signatur	Band/Heft/Jahr	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

Digitale Medien

Carbon-13 NMR microstructural characterization of dichlorocarbene adducts of polybutadiene (1983)

Komoroski, Richard A. ; Horne, Samuel E. ; Carman, Charles J.

New York : Wiley-Blackwell

Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 89-96

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 0360-6376

Schlagwort(e): Physics ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie

Notizen: 13C-NMR has been used to examine a number of dichlorocarbene adducts of cis- and trans-polybutadiene prepared in a two-phase system. Dichlorocarbene was generated by reaction of aqueous or solid NaOH or KOH with CHCl3 in the presence of a phase transfer catalyst. Monomer compositions, comonomer sequence lengths, and stereochemical information were obtained for the resulting polymers. The polymers examined here were stereochemically pure and were treated as simple copolymers. Samples prepared using aqueous NaOH can be described as essentially random copolymers over the entire range of monomer composition. Samples prepared using solid alkali-metal hydroxides contain a higher fraction of blocked units than a polymer of comparable composition prepared using aqueous NaOH. This blockiness can coincide with the presence of two glass transition temperatures and a two-phase morphology as seen by transmission electron microscopy. Fractionation of a substantially blocked sample yielded a chlorine-poor fraction which was a random copolymer and a chlorine-rich fraction which was more blocked than the original unfractionated material.

Zusätzliches Material: 3 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/pol.1983.170210110

Permalink

Bibliothek	Standort	Signatur	Band/Heft/Jahr	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

Treffer 1 - 5 | 5 Treffer