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  • 1975-1979  (27)
  • 1965-1969  (10)
  • 1830-1839
  • Polymer and Materials Science  (37)
  • 1
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Light scattered from a macromolecular solution in a capillary tube is used to determine both the sedimentation and translational diffusion coefficients. The capillary tube is spun in a preparative centrifuge, removed, and placed in a light-scattering photometer equipped with a scanning mechanism. The intensity distribution of scattered light along the tube represents the concentration profile in the tube and provides the measure of boundary migration. The sedimentation coefficient is determined from this measure and the applied centrifugal field. The diffusion coefficient is obtained from a time-autocorrelation analysis of fluctuations in intensity of light scattered from any fixed point of the profile. These coefficients were obtained for two monodisperse systems, R17 bacteriophage and 28s ribosomal rat liver RNA. The molecular weights obtained from ratios of these coefficients are in good agreement with literature values. In the sedimentation analysis, deviations from linearity between boundary displacement and applied field were found to be less than 1%. This precision confirms that the boundary is stable for the capillary geometry even in the absence of a preformed density gradient. The sedimentation coefficients of identical samples were also measured with the Spinco Model E analytical ultracentrifuge; results of the two methods agree to within 4%.As a consequence of the capillary tube geometry and light-scattering detection, sedimentation coefficients can be obtained from sample volumes of less than 100 μl. This detection techniques is thus far demonstrated to be at least an order of magnitude more sensitive than Schlieren optics, thereby useful when uv absorption is not applicable. For diffusion measurements there are also several inherent advantages. The diffusion coefficient is obtained from the identical sample, and scanning provides the capability to measure D from various parts of the sedimentation profiles and thereby directly explore concentration dependence, homogeneity, and integrity of the sample. The capillary tube with a layer of silicone oil over the sample and centrifugation provides an effective method to cleanse the solution and trap all dust.
    Additional Material: 5 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 178 (1977), S. 631-634 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Dihydroxy(phthalocyanino)germanium (1b) and Dihydroxy(tetraphenylporphino)germanium (3b) react with different monovalent alcohols to afford low-molecular bisalkoxyderivatives (1c-f and 3c-h). With bivalent alcohols and phenols polymers of the structure 5 and 6 or 8a, 9a and 8b, 9b, resp., are obtained.Dichloro(phthalocyanino)germanium (1a) and Dichlor(tetraphenylporphino)germanium (3a) react also with phenol, resp. hydroquinone, to give low-molecular and polymeric phenoxy-derivatives. The reaction of 1b and 3b with mono- and dibasic carboxylic acids leads to the corresponding esters.Dehydration of 3b gives polymeric porphin 15.The IR-spectra of the prepared compounds are discussed and compared with the analogous complexes of hemiporphyrazingermanium.Thermogravimetric and semiconductive measurements (σ298K = 10-10 - 10-15Ω-1 cm-1) are described.
    Notes: Dihydroxyphthalocyaningermanium (1b) und Dihydroxytetraphenylporphingermanium (3b) werden mit verschiedenen einwertigen Alkoholen zu den niedermolekularen Bisalkoxy-Derivaten (1c-f bzw. 3c-h) umgesetzt. Mit zweiwertigen Alkoholen und Phenolen können Polymere der Struktur 5 und 6 bzw. 8a, 9a und 8b, 9b erhalten werden.Dichlorphthalocyaningermanium (1a) und Dichlortetraphenylporphingermanium (3a) reagieren mit Phenol bzw. Hydrochinon ebenfalls zu niedermolekularen und polymeren Phenoxy-Derivaten. Die Umsetzung von 1b und 3b mit ein- und zweibasischen Carbonsäuren führt zu den entsprechenden Estern.Durch Dehydratisierung von 3b kann das polymere Porphin 15 hergestellt werden.Die IR-Spektren der dargestellten Verbindungen werden im Vergleich zu den analogen Hemiporphyrazingermaniumkomplexen diskutiert. Thermogravimetrische und Halbleitermessungen (σ298 K = 10-10 - 10-15Ω-1 cm-1) werden beschrieben.
    Additional Material: 6 Tab.
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  • 4
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Dihydroxy(meso-tetraphenylporphino)tin (1b), dihydroxy(phthalocyanino)tin (1d), and dihydroxy(hemiporphyrazino)tin (1f) react with bivalent phenols to afford polymers of type B. With 1,2-ethanediol and 1b low molecular compound 3 is obtained, which eliminates 1,2-ethanediol to give poly[oxyethyleneoxy(meso-tetraphenylporphin)stannandiyl] (4). Dehydration of the dihydroxy compounds 1b, 1d, 1f leads to polymers of type C. The IR-spectra of the prepared compounds are discussed; thermogravimetric and semiconductive measurements (σ298K≈10-6-10-16Ω-1cm-1) are described and compared with the analogous complexes of germanium.
    Notes: Dihydroxy-meso-tetraphenylporphinzinn (1b), Dihydroxyphthalocyaninzinn (1d) und Dihydroxyhemiporphyrazinzinn (1f) reagieren mit zweiwertigen Phenolen zu Polymeren des Typs B. Aus Äthylenglykol und 1b läßt sich die niedermolekulare Verbindung 3 erhalten, die unter Äthylenglykolabspaltung Poly[oxyäthylenoxy(meso-tetraphenylporphin)stannandiyl] (4) ergibt.Durch Dehydratation der Dihydroxy-Verbindungen 1b, 1d, 1f lassen sich Polymere des Typs C synthetisieren.Die IR-Spektren der dargestellten Verbindungen werden diskutiert; thermogravimetrische und Halbleitermessungen (σ298K≈10-6-10-16Ω-1cm-1) werden beschrieben und mit den analogen Germaniumverbindungen verglichen.
    Additional Material: 4 Tab.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 22 (1978), S. 719-725 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A variety of blends of ABA poly(styrene-b-isoprene) copolymers with poly(2,6-dimethylphenylene oxide) were prepared. Their compatibility was examined by measuring both the apparent modulus of rigidity and the loss tangent. Several blends showed a unique glass transition temperature between those of the individual components, which indicated compatibility. It was found that only those copolymers which phase separate are compatible with poly(2,6-dimethylphenylene oxide).
    Additional Material: 5 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 10 (1979), S. 449-455 
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: The Prevention of Inertial Force Measurement Inaccuracies Encountered in Pendulum-type DynamometersTest machines, which are equipped with a force measuring device utilizing the inclining pendulum, are subject to dynamic measurement inaccuracies due to the inertia of the pendulum.The initial discussion demonstrates that the dynamic inaccuracy of measurement encountered with test machines using an inclining pendulum - force measurement device can only be calculated for the complete test machine/test piece configuration. With reference to the results of experiments, it will be proved that, as with the experiments carried out by Kravcenko, the indicated dynamic force and the dynamic force in the testpiece are antiphase and unequal.Additionally it will be shown that, through the experiment results, the equation from Schultze/Baumann for the permissible rate of test is confirmed only in the interpretation from Kravcenko.Further equations concerning the limitations of the rate of test are shown and their relevant fields of applications are discussed. Finally, factors are presented which stipulate a reduction of the permissible rate of test or permit an increase in this rate, dependent upon the force-elongation characteristic of the test piece and the measured variable under consideration.
    Notes: An Prüfmaschinen, welche Kraftmeßeinrichtungen mit Neigungspendeln besitzen, treten durch die Trägheit des Pendels dynamische Meßfehler auf.Es wird zunächst klargestellt, daß die dynamischen Meßfehler bei Prüfmaschinen mit Neigungspendel-Kraftmeßeinrichtungen nur für das Gesamtsystem Prüfmaschine/Probe berechnet werden können.Anhand von Versuchsergebnissen wird nachgewiesen, daß - entsprechend Untersuchungen von Kravčko - die angezeigte dynamische Kraft und die dynamische Probenkraft gegenphasig und ungleich sind. Außerdem wird gezeigt, daß durch die Versuchsergebnisse die Gleichg. von Schultze/Baumann für die zulässige Prüfgeschwindigkeit nur in der Deutung von Kravčko bestätigt wird.Weitere Gleichungen für Die Begrenzung der Prüfgeschwindigkeit wer den angegeben und ihr Einsatzbereich besprochen. Schließlich werden Faktoren angegeben, die je nach dem Kraft-Verlängerungs-Verhalten der Probe und je nach der gesuchten Meßgröße eine Verringerung der zulässigen Prüfgeschwindigkeit bedingen oder eine Vergrößerung der selben zulassen.
    Additional Material: 7 Ill.
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  • 7
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Electrostatic powder coating - a modern surface coating method, saving energy and raw materials by respecting environmental regulationsLiquid paints and painting procedures are known every-where as problematical with regard to solvent emissions and sludge.Contrary to this problems, electrostatic powder coating is the most favourable solution and method offering the highest safety of all known surface coating materials and application methods for industrial finishes with regard to pollution control and environmental safety directions.Powders have been used in Europe in the field of decorative finishing since about 1966. Application of powder coatings has expanded in various fields in view of its advantages in the field of economics. These fields of application are in domestic appliances, metal furniture, automotive components and accessories industries and so on.Also pipe coating with powders became important mainly in the United States.By the implementation of modern recovery systems a material yield of up to 99% can be achieved by meeting at the same time all anti-pollution regulations.During the stoving process no side products are split off except approximately 1/2% water.In principle the powder coating method does not produce powder waste. In case that powder waste occurs it can be deposited without fear on normal refuse dumps.The energy balance for powders is very favourable. Production of 1 square meter coating film requires a very low crude oil equivalent in comparison to other systems.By developing better processing plants application of powder coatings has increased considerably.The use of powder coatings, however, is restricted due to the following reasons: -a minimum stoving temperature of approx. 130° - 140° centigrade is required for curing-a minimum film thickness of approx. 30 m̈ is only achievable at present-colour changes are so far rather time consuming-the necessity to reconstruct existing paint plants for use with coating powders.
    Notes: Durch Lackverfahren treten in der BRD wesentliche Emissionen an Lösemitteln und Lackschlamm auf. Von den zur Verringerung dieser Probleme neu entwickelten Lack-Materialien und -Verfahren ist die elektrostatische Pulverlackierung sicher das umweltfreundlichste Verfahren zur industriellen Serienlackierung. Es wird zur dekorativen Metall-Lackierung in Europa bereits seit 1966/67 eingesetzt und hat sich auch aufgrund guter Wirtschaftlichkeit vor allem auf folgenden Märkten expansiv entwickelt: Haushaltsgeräte, Automobile, Drahtwaren, Metallmöbel, Maschinenbauteile. In den USA ist darüber hinaus die Beschichtung von Rohren wichtig.Beim Einsatz von Pulverlacken ist aufgrund des fast 100%igen Wirkungsgrades eine sehr hohe Materialausnutzung gegeben. Durch Einsatz moderner Rückgewinnungsanlagen lassen sich alle Beschränkungen der TA-Luft weit unterschreiten. Beim Einbrennen wird - außer etwa 1/2% Wasser - praktisch nichts abgespalten. Pulverabfälle fallen nicht systematisch an und können auf normalen Hausmülldeponien abgelagert werden.Die Werte für die Applikationsenergie sind günstig. Zur Erzeugung von 1 m2 Film ergibt sich ein sehr niedriges „Erdöläquivalent“.Durch die Entwicklung neuer Verarbeitungsanlagen hat die Applikation von Pulverlacken wesentliche Verbesserungen erfahren.Der Einsatz von Pulverlacken wird begrenzt durch die zum Einbrennen benötigte Mindesttemperatur (ab 130-140°C), durch die derzeit erreichbare Mindestschichtdicke (ab 30 m̈), durch einen gewissen Aufwand beim Material(Farb)wechsel und die Notwendigkeit des Umbaus der Verarbeitungsanlage.
    Additional Material: 1 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 29 (1978), S. 804-815 
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Electron beam microanalysis of surface layers on galvanized hot-water steel tubesIn connection with investigations on the influence of copper over the corrosion behaviour of galvanized tubes in waters of 65°C, the structure of the surface layers was of special interest.Therefore the distribution of the elements building the layers is determined by electron beam microanalysis.The arrangement of chloride and sulfate shows that the surface layer may be partially semiconducting. The distribution of other elements favours this opinion. On the basis of the copper distribution and other considerations a hypothesis on the influence of copper as a pitting-promoter is made.
    Notes: Im Anschluß an Untersuchungen über den Einfluß von Kupfer auf das Korrosionsverhalten verzinkter Rohre in warmen Wässern, t = 65°C, interessierte der Aufbau der aus Korrosionsprodukten gebildeten Rohrdeckschichten in vielfältiger Hinsicht. Aus diesem Grunde ist mit Hilfe der Mikrosonde die Verteilung der Elemente des Rohrmaterials und der Wasserinhaltsstoffe in Deckschichten verzinkter Rohre aus diesen Untersuchungen ermittelt worden. Aufgrund der vorgefundenen Anordnung der Neutralsalzionen Chlorid und Sulfat werden der Deckschicht halbleitende Eigenschaften zugeschrieben, die zu einer zumindest teilweisen Trennung der anodischen und kathodischen Teilreaktionen der Rohrkorrosion führen. Diese Anschauung wird durch Ablagerungen von Kupfer sowie von Kalk, Silikaten und Phosphaten an der Phasengrenze Deckschicht/Wasser unterstützt. Anhand der Kupferverteilung in der Deckschicht von vorverkupferten und von kupferhaltigem Wasser ausgesetzten Rohren sind Überlegungen über die lochkorrosionsinduzierende Wirkung des Kupfers angestellt worden. Hiernach wird vermutet, daß gelöstes Kupfer selbst als Oxydationsmittel wirkt und somit die Metallauflösung an Lokalanoden stimuliert.
    Additional Material: 9 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 5 (1967), S. 123-130 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Calf thymus and salmon sperm deoxyribouncleie acid were degraded by high-shear stirring to molecular weights M in the range of 1.3-3.2 × 106 and purified by chromatography on methylated bovine serum albumin. Dynamic viscoelastic properties of the fragmented products, in aqueous glycerol solutions in the concentration range of c = 0.003-0.01 g./ml., were investigated with the apparatus of Birnboim and Ferry. At values of the product cM higher than 4 × 103, the frequency dependence of the components of the complex shear modulus, G′ and G″, displayed a plateau region in which G′ 〉 G″ - ων1ηS, similar to that observed in concentrated solutions of coiling polymers where it is attributed to an entanglement network (ω is radian frequency, ν1 volume fraction of solvent, and η8, solvent viscosity). The width of this plateau region on the logarithmic frequency scale is given by Δ = 3.8 (log cM - 3.56). At lower values of cM, the frequency dependence is intermediate between those predicted by the theory of Zimm for flexible coiled macromolecules and by the theory of Kirkwood and Auer for rods. Fitting to the Zimm theory gives highly discrepant values for molecular weights, while fitting the low-frequency end of the dispersion to the Kirkwood-Auer theory gives reasonable agreement for both molecular weight and rotary diffusion coefficient. It is concluded that the helical fragments appear as nearly rigid rods in their behavior at very low frequencies, but at higher frequencies reveal substantial bending flexibility.
    Additional Material: 3 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 57 (1977), S. 211-224 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The polymerization of ethylene and 1-octene with supported Ziegler-catalysts was investigated with regard to the influence of mass transport of monomers on the kinetics, molecular weight and molecular weight distribution.In the case of the polymerization of ethylene, it was found that for certain conditions of reaction the mass transport of ethylene can influence the kinetics of polymerization respectively the catalyst efficiency strongly.The molecular weight and molecular weight distribution of the polyethylene formed are practically not affected by the conversion as well as particle size of catalyst and polymer. The molecular weight distribution however is affected by the concentration of the catalyst. The polymerization process of ethylene in suspension is distinguished by chemical and physical processes. A continuous chain initiation, for example, is based on the continuous reduction of the catalyst particles to small pieces during the course of polymerization. An apparent chain termination respectively catalyst deactivation can occur when catalyst particles are encapsulated within the growing polymer particles.The polymerization of 1 -octene for similar conditions of reaction gave polymers which were solved completely in the system used. The molecular weight distribution of the polymer formed nevertheless was very broad. This indicates that the mass transport of the monomers through the solid phase of polymer cannot be the main reason for the broad molecular weight distribution of the polymers which are produced by heterogeneous Ziegler-catalysts in suspension.
    Notes: Untersucht wurde die Polymerisation von Äthylen und Okten-1 mit Ziegler-Katalysatoren auf Basis von TiCl4/Mg(OC2H5)2/Aluminiumtrialkyl unter dem Gesichtspunkt des Stofftransportes und sein Einfluß auf Kinetik, Molekulargewicht und Molekulargewichtsverteilung.Es zeigt sich im Falle der Äthylenpolymerisation, daß der Stofftransport des Äthylens durch das dreiphasige System unter bestimmten Reaktionsbedingungen einen ausgeprägten Einfluß auf das kinetische Verhalten der Polymerisation bzw. auf den Katalysator-Nutzungsgrad ausüben kann.Molekulargewicht und Molekulargewichtsverteilung des Polyäthylens scheinen weitgeheß unabhängig zu sein von Umsatz, Katalysator- und Polymerpartikelgröße, jedoch zeigt sich eine eindeutige Abhängigkeit von der Katalysatorbeladung des Systems. Das Polymerisationsgeschehen des Äthylens ist gekennzeichnet durch chemische und physikalische Teilschritte. So beruht der fortgesetzte Kettenstart auf einer fortgesetzten Neubildung von Katalysatoroberfläche infolge einer fortgesetzten Zerkleinerung der Katalysatorpartikeln während der Polymerisation durch das sich bildende Polymere. Auch kann es zu einer ausgeprägten Einkapselung der Katalysatorpartikeln durch das Polymere kommen. was einem scheinbaren Kettenabbruch bzw. einer Katalysator-Desaktivierung entspricht.Die Polymerisation des Oktens führt zu Polymeren, welche im verwendeten Lösungsmittel vollständig löslich sind. Trotzdem weist das gebildete Polyokten eine relativ breite Molekulargewichtsverteilung auf und spricht somit ebenfalls dafür, daß der Stofftransport des Monomeren durch die Polymerphase nicht die hauptsächliche Ursache für die Einstellung der breiten Molekulargewichtsverteilung dieser Polymeren sein kann.
    Additional Material: 8 Ill.
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