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Comparison of the rheology of polymer melts in shear, and biaxial and uniaxial extensions (1987)

Khan, S. A. ; Prud'homme, R. K. ; Larson, R. G.

Springer

Rheologica acta 26 (1987), S. 144-151

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ISSN: 1435-1528

Schlagwort(e): Extensional deformation ; polymer melt

Quelle: Springer Online Journal Archives 1860-2000

Thema: Chemie und Pharmazie , Physik

Notizen: Abstract The experimental properties of different polymer melts, polystyrene, high density polyethylene and low density polyethylene are compared for the first time in three different deformations: step shear, step biaxial extension and steady uniaxial extension. Properties of three other melts are also studied in step biaxial and shear experiments. For our comparative purposes some data of Laun and Winter from the literature are used, as well as new data reported here. In all the step strain experiments, the stresses can be factored into a time dependent relaxation modulus and a strain dependent damping function. The data are interpreted using a differential constitutive equation of Larson which satisfies this time-strain separability and has a single parameter that describes the strain softening character of the material. Results show that differences in the properties of the melts are most pronounced in uniaxial extension and least in biaxial extension. All melts follow the Doi-Edwards prediction relatively closely in biaxial extension. In uniaxial extension, the branched material shows a strong strain hardening effect although its shear and biaxial properties are similar to the other melts. The constitutive model gives a reasonably good fit to the data in all three deformations for unbranched materials for the same value of the adjustable parameter; the model, however, fails for the branched low density polyethylene.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF01331972

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Digitale Medien

Studies on MM″(NCS)4 [M=Ni(II), Fe(II), Zn(II), and M″=Hg(II) Zn(II)] complexes (1976)

Singh, P. P. ; Khan, S. A.

Weinheim : Wiley-Blackwell

Zeitschrift für anorganische Chemie 423 (1976), S. 173-179

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ISSN: 0044-2313

Schlagwort(e): Chemistry ; Inorganic Chemistry

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie

Beschreibung / Inhaltsverzeichnis: Untersuchungen an MM″ (NCS)4-Komplexen (M = NiII, FeII, ZnII; M″ = HgII, ZnII)Komplexe des Typs MM′(NCS)4 · xL M = NiII, FeII, ZnII; M″ = HgII, ZnII; x = 2, 4, 6; L = Nicotinamid (nia), Isonicotinsaiurehydroxid (inh) 2-Aminopyrimidin (2apm)] wurden dargestellt und charakterisiert durch Elementaranalyse, molare Leitfähigkeit, magnetisches Moment, IR- und Elektronenspektren.

Notizen: Coordination complexes of the type MM″(NCS)4 · xL M = Ni(II), Fe(II), Zn(II), M″ = Hg(II), Zn(II), x = 2, 4, 6 and L = nicotinamide (nia), 3-cyanopyridine (3-cpy), 4-cyanopyridine (4cpy), 4-aminopyridine (4apy), isonicotinic acid hydrazide (inh), 2-aminopyrimidine (2apm)l have been prepared and characterized by elemental analysis, molar conductance, magnetic moment, infrared and electronic spectral studies. Molar conductance data of NiZn(NCS), complexes are equivalent to 1:1 electrolyte. The infrared spectral studies indicate that only bridged thiocyanate groups are present in the complexes of the type NiHg(SCN)4 · 4L [L=3 and 4cpy, inh] and FeHg(SCN)4 · 2L [L = nia, 2apm], whereas both bridged and terminal thiocyanates are present in the complexes of the type NiHg(SCN)4 · 4L [L = nia, 3apy and ZnHg(SCN)4 · 2(inh). BOHR magneton values and electronic spectral data indicate an octahedral environment around nickel and iron in their complexes. Symmetry and group theory have also been used to establish the structure of the complexes.

Zusätzliches Material: 2 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/zaac.19764230211

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Digitale Medien

Quantitative softness parameters and their application in elucidation of Structure of Bimetallic Tetrathiocyanate Complexes (1980)

Singh, P. P. ; Khan, S. A. ; Shukla, U. P.

Weinheim : Wiley-Blackwell

Zeitschrift für anorganische Chemie 461 (1980), S. 222-230

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ISSN: 0044-2313

Schlagwort(e): Chemistry ; Inorganic Chemistry

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie

Beschreibung / Inhaltsverzeichnis: Quantitative „Softness“ Parameter und ihre Anwendung in der Strukturaufklärung von Bimetalltetracyanat-Komplexen〉2M(NCS)2M′(SCN)2〈 und [Ml6][M′(SCN)4], (M = COII und NiII; M′ = ZnII, CdII und HgII, L = Anilin, p-Toluidin, Pyridin, Nicotinamid, 2,2′-Bipyridin und 4-Aminopyridin) wurden dargestellt und charackterisiert. Die Strukturen werden auf Grund von Leitfähigkeits-, magnetischen und spektroskopischen (IR und VIS) Messungen, sowie durch gruppentheoretische Berechnungen und Ligandenfeldparametern vorgeschlagen. Diese Strukturvorschläge werden gestützt durch quantitative „Softness“ - Werte „\documentclass{article}\pagestyle{empty}\begin{document}$ {\rm E}_{\rm n}^{_ + ^ +},{\rm E}_{\rm m}^{_{\rm +}^{\rm +}} $\end{document}“. Die totale „Softness“ von M und M′ und ihre Differenz \documentclass{article}\pagestyle{empty}\begin{document}$ \Delta {\rm TE}_{\rm n}^{_ + ^ +} \left({{\rm M} - {\rm M}'} \right) $\end{document} wurden abgeleitet (Gleichungen siehe Abstract) und mit der Struktur der Komplexe in Verbindung gebracht.

Notizen: 〉2M(NCS)2M′(SCN)2〈 and [ML6][M′(SCN)4], (M = Co(II) and Ni(II), M′ = Zn(II), Cd(II) and Hg(II) and L = aniline(ani), p-toluidine(tol), pyridine(py), nicotinamide(nia), 2,2′-bipyridine(bipy) and 4-aminopyridine (apy)) have been prepared and characterized. Their structure have been proposed on the basis of molar conductance, magnetic moment, group theoretical calculations, ligand field parameters, infrared and electronic spectral studies. The proposed structures have also been supported by quantitative values of softness „\documentclass{article}\pagestyle{empty}\begin{document}$ {\rm E}_{\rm n}^{_ + ^ +},{\rm E}_{\rm m}^{_{\rm +}^{\rm +}} $\end{document}“,. Total softness of M and M′ and their difference \documentclass{article}\pagestyle{empty}\begin{document}$ \Delta {\rm TE}_{\rm n}^{_ + ^ +} \left({{\rm M} - {\rm M}'} \right) $\end{document} have also been derived by the following equations and related to the structure of the complexes. \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm TE}_{\rm n}^{_ + ^ +} \left({\rm M} \right) = {\rm E}_{\rm n}^{_ + ^ +} \left({\rm M} \right) + \sum {\rm E}_{\rm m}^{_ + ^ +} \left({\rm L} \right) + \sum {\rm E}_{\rm m}^{_ + ^ +} \left({{\rm NCS}} \right) $$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm TE}_{\rm n}^{_ + ^ +} \left({{\rm M}}^\prime \right) = {\rm E}_{\rm n}^{_ + ^ +} \left({{\rm M}}^\prime \right) + \sum {\rm E}_{\rm m}^{_ + ^ +} \left({\rm L} \right) + \sum {\rm E}_{\rm m}^{_ + ^ +} \left({{\rm SCN}} \right) $$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$ \Delta {\rm TE}_{\rm n}^{_ + ^ +} \left({{\rm M} - {\rm M}^\prime} \right) = \,|\,{\rm TE}_{\rm n}^{_ + ^ +} \left({\rm M} \right) - {\rm TE}_{\rm n}^{_ + ^ +} \left({{\rm M}}^\prime \right)$$\end{document}.

Zusätzliches Material: 1 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/zaac.19804610134

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