ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles  (24,019)
  • Elsevier  (21,899)
  • Wiley-Blackwell  (2,120)
  • 1985-1989  (24,019)
  • 1950-1954
  • 1987  (24,019)
  • Physics  (24,019)
Collection
  • Articles  (24,019)
Years
  • 1985-1989  (24,019)
  • 1950-1954
Year
Journal
  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 150 (1987), S. 189-192 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A morphological study was made to examine the friction and wear mechanisms of ultrahigh molecular weight polyethylene in air and water by means of transmission electron microscopy of a carbon replica film of a very thin layer of the polymer surface slid against a steel ball. Electron diffractions revealed that a molecular orientation with a typical fiber pattern was formed in the friction in air, while thin ribbon-like crystals with particular crystal orientations were formed in water in a way that the sliding took place on the crystallographic a - c plane, giving rise to a low friction coefficient of the polymer.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 150 (1987), S. 137-150 
    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: Es wurde der relative Wirkungsgrad von fünf handelsüblichen Stabilisatoren bei Photooxidation und thermischer Alterung von Polypropylen (PP) anhand der Änderungen der mechanischen Eigenschaften untersucht. Es wurden Polypropylenproben mit unterschiedlichem Anteil an Cyasorb UV-531 hergestellt (bezeichnet als PC0.5-31, PC1-31, PC1.5-31 und PC2-31). Der Einfluß der Photooxidation auf das thermische Verhalten ist mit Hilfe der Differentialscanningkalorimetrie und durch thermogravimetrische Analysen untersucht worden. 2-Hydroxy-4-n-octyloxybenzophenon (2 Gew.-%) war am wirksamsten, Polypropylen, gegen Verfärbung und Brüchigkeit zu stabilisieren. Bei einer Probe mit 1% Stabilisatorzusatz fanden sich nach 32 h Bestrahlung noch 81% des ursprünglichen Wertes der Streckgrenze gegenüber 18% bei unstabilisiertem PP.
    Notes: The relative effectiveness of five commercially available stabilizers on the photooxidation and thermal ageing of polypropylene (PP) was investigated by following changes in mechanical properties. Samples of PP containing different percentages of Cyasorb UV-531 were prepared (designated as PC0.5-31, PC1-31, PC1.5-31, and PC2-31, respectively). The effect of photooxidation on thermal behaviour was investigated by differential scanning calorimetry and thermogravimetric analysis. 2-Hydroxy-4-n-octyloxy benzophenone (2% w/w) was most effective in stabilizing PP towards discolouration and brittleness. After 32 h irradiation, 81% retention in yield strength was observed in case of PC1-31 against 18% in case of PP.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 153 (1987), S. 113-124 
    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: Käufliche Weizenmehlstärke wurde unter Verwendung verschiedener Mengen Schwefelkohlenstoff und Acrylnitril xanthogeniert und cyanethyliert und dann zur Herstellung von modifizierten Stärke-Naturkautschuk-Masterbatches eingesetzt. Weiterhin wurden die Einflüsse untersucht, die die Gleichgewichte der Xanthogenierung und Cyanethylierung gegenseitig aufeinander ausüben. Die Ergebnisse werden auf der Basis definierter Wechselwirkungen zwischen der Xanthogenatgruppe und dem freien Acrylnitril erklärt. Hierbei führen sowohl sterische Faktoren als auch die höhere Elektrophilie des Acrylnitrils zum Zerfall der Xanthogenatgruppe. Daher kann die Cyanethylierung nur noch in einem geringeren Ausmaß erfolgen.
    Notes: Common wheat flour starch was subjected to xanthation followed by cyanoethylation at various levels of carbon disulfide and acrylonitrile to prepare modified starchnatural rubber masterbatches. Mutual influences of the extents of equilibrium xanthation and cyanoethylation on each other have been studied. The results have been explained on the basis of a definite interaction between xanthate group and free acrylonitrile in which both the steric factors and higher electrophilicity of acrylonitrile lead to the decomposition of xanthate groups and reduced the extent of cyanoethylation.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    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: Aus Polychloropren und Polyvinylchlorid wurden Blends in verschiedenen Zusammensetzungen hergestellt und ihre Eigenschaften bestimmt. Die Eigenschaften der Blends zeigen, daß sie Polychloropren in vielen Anwendungen ersetzen können.
    Notes: Blends of polychloroprene rubber and plasticized polyvinylchloride have been prepared in various compositions and their properties evaluated. The properties of the blends show that they can be used to replace polychloroprene in many applications.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    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 present paper describes a rheo-optical apparatus consisting of an elongational rheometer (with rotary clamps) and a device to measure birefringence. This equipment was designed to perform homogeneous deformations on polymer melts in the simple elongational mode. Elongational experiments were performed on polyisobutylene samples at room temperature using different strain rates (from \documentclass{article}\pagestyle{empty}\begin{document}$\dot \varepsilon$\end{document} 0.01 s-1 to 1 s-1). In typical experiments homogeneous elongations up to λ ≈ 200 and stresses up to 2 · 106 Pa were achieved. The stress, the birefringence, and the deformation were obtained by measuring the force, the sample thickness, the optical retardation (the frequency of the sampling was 20 Hz) and the width of the sample (the frequency of the sampling was 3 Hz). It was found that the stress-optical coefficient was constant. The homogeneity of the deformations was carefully controlled because inhomogeneities cause serious errors in the measurements of elongational viscosity and birefringence.
    Notes: Es wird über eine rheo-optische Apparatur zur Verstreckung von Polymerschmelzen mit rotierenden Klemmen berichtet, die mit einer Doppelbrechungs-Meßeinrichtung ausgerüstet ist. Mit dieser Einrichtung können einfache Dehnungen an Polymerschmelzen bis zu hohen Verstreckgraden unter homogenen Bedingungen durchgeführt werden. Während des Deformationsvorganges können die Spannung, die Doppelbrechung und die Probendicke mit einer Meßrate von 20 Hz, sowie die Probenbreite mit ca. 3 Hz erfaßt werden.Wir haben Messungen an Polyisobutylen bei Raumtemperatur mit verschiedenen Dehngeschwindigkeiten (0,01 s-1 〈 \documentclass{article}\pagestyle{empty}\begin{document}$\dot \varepsilon$\end{document} 〈 1 s-1) bis zu einem Verstreckgrad von λ ≈ 200 durchgeführt. Dabei wurden Spannungen bis zu 2 · 106 Pa erhalten. Das spannungsoptische Gesetz war bei homogener Versuchsführung stets erfüllt. Es wird gezeigt, daß ohne Kontrolle der Dehngeschwindigkeit und insbesondere bei inhomogener Dehung nicht nur Abweichungen vom spannungsoptischen Gesetz, sondern auch große Fehler bei der Spannungs- bzw. Viskositätsberechnung auftreten. Deshalb wurde großer Wert auf die Prüfung der Homogenität der Dehnung gelegt.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 153 (1987), S. 187-195 
    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 miscibility of various polymethylmethacrylate (PMMA)/polybutylmethacrylate (PBMA)/poly(methylmethacrylate-co-butylmethacrylate)systems has been studied. PMMA and PBMA are immiscible. Methacrylic homopolymers and copolymers are immiscible, too. A one-phase mixture from PMMA and PBMA is only accessible by copolymerization.
    Notes: Die Mischbarkeit von verschiedenen Systemen aus Polymethylmethacrylat (PMMA), Polybutylmethacrylat (PBMA) und Poly(methylmethacrylat-co-butylmethacrylat) (P(MMA-co-BMA)) wurde untersucht. PMMA und PBMA sind miteinander nicht mischbar. Die untersuchten Homopolymeren und entsprechende Methacrylatcopolymere bilden ebenfalls heterogene Systeme. Einphasige Mischungen aus PMMA und PBMA sind nur über Copolymerisation erreichbar.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    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: Mit Hilfe der 13C-NMR-Spektroskopie wurde die Entwicklung der Oligomerenverteilung während der Polymerisation von 13C-angereichertem Ethylen mit dem löslichen Ziegler-Katalysatorsystem Cp2TiMeCl/AlMe2Cl verfolgt. Zuordnung und quantitative Auswertung aller Signale der verschiedenen wachsenden Ketten werden beschrieben. Die Geschwindigkeiten der Ethylen- und der Cp2 TiMeCl-Abnahme sowie die Bildungsgeschwindigkeit neuer Ketten konnten direkt aus den Spektren ermittelt werden. So läßt sich zum ersten Mal zeigen, daß die Konzentration der Ti-Propyl-und Ti-Pentylspezies in einen stationthen Zustand einlaufen. Dies ermbglicht, die Geschwindigkeitskonstanten der Ethyleninsertion in die Ti-Kohlenstoffbindung von Ti-Me, Ti-Pr und Ti-Pe zu ermitteln. Diese Ergebnisse fiihren zu einem detaillierten Ein-blick in den Ablauf der ersten Insertionsschritte und sind so eine Grundlage fur die mathematische Modellierung. Sie sind aufierdem ein weiterer unabhlngiger Beweis für die Giiltigkeit des dynamischen Modells des Mechanismus der Ethylenpolymerisation mit lbslichen Ziegler-Katalysatoren, nlmlich die Bildung der polymerisationsaktiven Spezies in zwei aufeinanderfolgenden sehr dynamischen Gleichgewichtsreaktionen.
    Notes: The development of the oligomer distribution during the polymerization of 13C-enriched ethylene by the soluble Ziegler catalyst system Cp2 TiMeCl/AlMe2Cl was followed by 13C-NMR spectroscopy. The assignment of the signals from the growing chains is described in full. It is shown that the rate of consumption of ethylene and Cp2 TiMeCl and the rate of formation of new chains can be monitored directly from the spectra. The concentrations of Ti-propyl and Ti-pentyl species during the polymerization were followed spectroscopically; both attain a steady state concentration. The relative rates were determined for the insertion of ethylene in the Ti-carbon bond of Ti-Me, Ti-Pr and Ti-Pe. These results give a detailed insight into the way that the oligomer distribution develops and provide a basis for its computer simulation. They also provide an independent proof that the dynamic model for the mechanism of ethylene polymerization with soluble Ziegler catalysts of the type Cp2 TiRCl/AlRnClm is correct.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 154 (1987), S. 99-110 
    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: Der Einfluß verschiedener Reaktionsbedingungen auf die Bromierung von ataktischem Poly(propylen) (APP) in Tetrachlorkohlenstofflösung wurde untersucht. Mit zunehmender Reaktionszeit steigt der Bromierungsgrad. Auch mit steigender Verdünnung der APP-Lösung nimmt die Bromierungsgeschwindigkeit zu, welche bezüglich der APP-Konzentration die Ordnung 0,66 hat. Dies wird erklärt durch die anfängliche Substitution eines Wasserstoffs am tertiären Kohlenstoffatom. Die folgende H-Abstraktion an den benachbaren sekundären und primären Kohlenstoffatomen ist erleichtert. Die scheinbare Aktivierungsenergie wurde zu 11,9 kcal/mol bestimmt. Die Bromierungsgeschwindigkeit steigt bis zu einem APP : Br2-Molverhältnis von 1 : 1 an, darüber hinaus wird die Geschwindigkeit unabhängig vom Molverhältnis. Die Bromierung scheint folgendermaßen zu verlaufen: Nach anfänglicher Substitution eines tertiären H-Atoms durch freie Bromradikale werden nach und nach auchdie sekundäen und primären H-Atome durch weitergehende Substitution oder durch Addition nach einem Eliminierungsschritt ersetzt. Das IR-Spektrum bestätigt die Anwesenheit von Brom in den Proben.
    Notes: Effects of various reaction conditions on bromination of atactic poly(propylene) (APP) in carbon tetrachloride solution were studied. It was found that with the increase of the reaction time the extent of bromination increases. Also with an increased dilution of APP the rate of bromination increased following a bromination order of 0.66 with respect to APP concentration. This has been ascribed to initial replacement of the hydrogen at the tertiary carbon atoms followed by enhanced ease of abstraction from the neighbouring secondary and primary carbon atoms. The apparent activation energy was found to be 11.9 kcal/mol. The rate of bromination increases with an increase of the APP: Br2 molar ratio up to 1 : 1, beyond which the rate becomes independent of this ratio. Mechanism of bromination appears to be an initial substitution of tertiary H-atoms by bromine radicals followed subsequently by replacement of secondary and primary H-atoms via either progressive substitution or elimination-addition. IR spectra confirm the presence of bromine in the samples.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    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: Es wurden kationische Polyurethane mit Piperazinringen in der makromolekularen Kette hergestellt. Die Polymeren bilden elastische und lichtdurchlässige Filme. Das Verhalten der verdünnten Lösungen in Lösungsmitteln mit verschiedenen Dielektrizitätskonstanten wurde untersucht.
    Notes: Cationic polyurethanes containing piperazine rings on the macromolecular chain were synthesized. The polymers form flexible and transparent films. The behaviour of diluted solutions in solvents of different dielectrical constants was studied.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 147 (1987), S. 113-122 
    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: In der vorliegenden Arbeit werden die Charakteristika von pigmentiertem Polypropylen (PP) untersucht. Die Ergebnisse zeigen, daß die Fließeigenschaften von PP-Schmelzen, die Morphologie und das Zugverhalten der Fasern deutlich von der Anwesenheit verschiedener, in der PP-Matrix dispergierter Pigmente beeinflußt werden. Die Auswirkungen verschiedener, dem PP zugefügten Pigmente zeigen große Unterschiede. Der Fließwiderstand von PP steigt mit Zugabe von Phthalocyaninblau, Ruß und Titandioxid, fällt aber bei der Anwesenheit von “BR red” und “GL orange” Die Strangaufweitungseffekte der PP-Schmelze werden durch Addition dieser Pigmente intensiviert. Die Elastizitätsgrenze von Fasern mit stäbchenförmiger Struktur ist 80-125% niedriger als die von Fasern mit Sphärulitstruktur.
    Notes: In this paper the characteristics of polypropylene (PP) containing pigments are systematically studied. The results show that the flow properties of PP melt, morphological structures, and drawing behaviour of the fibres are obviously affected by the presence of certain pigments dispersed in the PP matrix. The effects of various pigments added in PP display great difference. The flow resistance of PP increases with the addition of phthalocyanine blue, carbon black, and titanium dioxide, but decreases with the presence of BR red and GL orange. The extrudate swell effects of PP melt are intensified by adding these pigments. The yield stress of filaments with rod structure is 80-125% lower than that of filaments with spherulitic structure.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 147 (1987), S. 147-156 
    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 grafting of a liquid acrylic derivative (2-methylenepentane-1,5-dicarboxylic acid diethylester) on the surface of a polyethylene film (HD) was carried out in the presence of benzoylperoxide. The wettability of the surface was investigated with respect to the adhesion properties against aluminium and compared with those of a film of polyethylene grafted in mass with acrylic acid. The mobility of the surface grafted chains may cause the differences in the observed comportment.
    Notes: Le greffage d'un dérivé acrylique liquide (méthylène-2 pentanedïoate-1,5 de diéthyle) est effectué en présence de peroxyde de benzoyle à la surface d'un film de polyéthylène (HD). Les propriétés de mouillabilité de la surface sont examinées en relation avec les propriétés d'adhésion vis à vis de l'aluminium, et comparées avec celles d'un film de polyéthylène greffé dans la masse à l'acide acrylique. La mobilité des chaǐnes greffées à la surface pourrait ětre à l'origine des différences de comportement observées.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 150 (1987), S. 151-159 
    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: Die Polymerisation von Methacrylamid wurde in wäßriger Phase unter Verwendung von Persulfat/Äpfelsäure und Persulfat/Ethanolamin als Redox-Systeme unter Stickstoff untersucht. Bezüglich des Persulfats wurde für beide Fälle eine Reaktion erster Ordnung gefunden, für Äpfelsäure ergab sich die Ordnung 1/2, für Ethanolamin nullte Ordnung. Für Methacrylamid wurde im Ansatz mit K2S2O8/Äpfelsäure erste Ordnung und im Ansatz mit K2S2O8/Ethanolamin die Ordnung 1,5 gefunden. Das mittlere Molekulargewicht wurde viskosimetrisch für die unter verschiedenen Bedingungen erhaltenen Proben bestimmt.
    Notes: The aqueous polymerization of methacrylamide was studied by using persulphate/malic acid and persulphate/ethanolamine redox pairs under nitrogen atmosphere. The order with respect to persulphate was found to be one half with both the redox systems. Malic acid and ethanolamine show half order and zero order, respectively. Methacrylamide has first order dependence on the rate of polymerization initiated by K2S2O8-malic acid system and one and half order dependence on the rate of polymerization initiated by K2S2O8-ethanolamine redox pair. Viscometric average molecular weight was determined for the samples obtained under different kinetic conditions.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 150 (1987), S. 1-11 
    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: Ataktisches Polypropylen wurde durch die Umsetzung mit Dicumylperoxid (8 Gew.-%) und einer Allylverbindung (8 Gew.-%) (Eugenolmethylether, Allylphenylether, Allylharnstoff, N-Allylthioharnstoff, Allylmalonsäurediethylester und N-Allylanilin) bei 170°C funktionalisiert. Bei der Reaktion von tert-Butylazidoformat mit ataktischem Polypropylen wurden maximal 1,8 Gew.-% Carbamatgruppen in das Polymere eingebaut. Die Mechanismen der beiden Reaktionstypen werden diskutiert.
    Notes: Atactic polypropylene was functionalized by reaction with dicumyl peroxide (8 wt.-%) and allyl compounds (8 wt.-%) such as eugenol methylether, allylphenylether, allylurea, N-allylthiourea, diethyl allylmalonate, N-allylaniline at 170°C. Using tert-butyl azidoformate carbamate groups (1.8 wt.-%) were attached to atactic polypropylene. The mechanism of both types of reactions is discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 150 (1987), S. 21-32 
    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: Es wurde die elektrische Leitfähigkeit von Styrol-Butadien-Kautschuk (SBR-1502), der mit unterschiedlichen Konzentrationen von sehr schnell spritzbarem Furnace-Ruß (70, 80, 90 und 100 phr) beladen war, untersucht. Auf der Basis des Modells von Holm wurde eine qualitative Beschreibung für die elektrische Leitfähigkeit durch diese Verbundstoffe gesucht. Der Druckkoeffizient K wurde berechnet und zeigte eine starke Abhängigkeit von den Rußkonzentrationen.
    Notes: The electrical conduction was investigated in styrene butadiene rubber (SBR-1502) loaded with different concentrations of fast extrusion furnace (FEF) black (70, 80, 90, and 100 phr). On the bases of Holm's model, a qualitative description for the electrical conduction through these composites was sought. The pressure coefficient K was calculated and found to be strongly dependent on the carbon black concentrations.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 150 (1987), S. 13-19 
    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: Es wird ein Verfahren zur Bestimmung der niedermolekularen Anteile von Instrumententafel-Folien beschrieben. Die Lösungsmittel-Extrakte der Folien werden mit Hilfe der präparativen Umkehr- bzw. Normalphasen-HPLC fraktioniert und die Fraktionen über ihre IR-Spektren charakterisiert. Vorzüge und Nachteile beider Verfahren werden diskutiert.
    Notes: A procedure to obtain information concerning the low molecular weight compounds of dashboard foils is described. Solvent extracts of the foils were fractionated by preparative reversed or normal phase HPLC, respectively. The fractions were characterized by their infrared spectra. The benefits and the shortcomings of the two methods are discussed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    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: A synergetic model is proposed for the development of the surface structure on UV-Laser irradiated polymers and especially synthetic fibres. It is suggested that thermal contributions to the UV-laser-polymer-interaction produce a very thin, highly heated layer of molten material at the ablation limit. The formation of the typical surface structure is then thought to be caused by Marangoni-convection and shrinkage because of intrinsic stress. The parameters of the effect therefore are the absorption coefficient for the corresponding laser wavelength as a measure of the thickness of the molten layer and the existence of the shrinking behaviour.
    Notes: Ein synergetisches Modell wird vorgeschlagen für die Entstehung der Oberflächenstruktur von UV-laserbestrahlten Polymeren und speziell Synthesefasern. Dabei wird angenommen, daß durch thermische Beiträge zur UV-Laser-Polymer-Wechselwirkung eine sehr dünne, hocherhitzte Schmelzschicht an der Ablationsgrenze entsteht. Das Zusammenwirken von Marangoni-Konvektion und Schrumpfverhalten aufgrund innerer Spannungen ist dann für das Entstehen der typischen Struktur verantwortlich. Parameter für das Auftreten des Effekts sind hierbei der Absorptionskoeffizient für die jeweilige Wellenlänge, der die Dicke der Schmelzschicht bestimmt, sowie die Existenz des Schrumpfes.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 151 (1987), S. 69-83 
    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: Es wurden neue organofunktionelle Siloxane aus γ-Methacryloxypropyltrimethoxysilan (MPTMS) durch Umesterung von Methoxygruppen mit linearen höheren Alkoholen, Etheralkoholen und α-Hydroxysäuren hergestellt. Die Faktoren die die Substitutionsverhältnisse beeinflussen, wurden bestimmt.Diese Siloxane wurden mit Methylmethacrylat (MMA) copolymerisiert und mit Ethylenglykoldimethacrylat vernetzt, um den Einfluß der substituierten Gruppen auf den Sauerstoffpermeabilitätskoeffizienten (Pd) und die Eigenschaften der freien Oberflächenenergie der resultierenden Polymeren zu prüfen.Die Substitution der Sauerstoff enthaltenden polaren Gruppen erniedrigte die Sauerstoffdurchlässigkeit wegen der Wechselwirkungen zwischen den polaren Gruppen, die das freie Volumen erniedrigen. Diese Gruppen jedoch erhohten die polare Komponente der freien Oberflächenenergie (γPS) und somit die gesamte freie Oberflgchenenergie (γS). Die Hydrophilie der Carbitol und 2-Ethoxyethanol enthaltenden Siloxan-Methylmethacrylat-Copolymeren macht sie fur biomedizinische Anwendungen geeignet.
    Notes: New organofunctional siloxanes from γ-methacryloxypropyltrimethoxysilane (MPTMS) were synthesized by transesterification of methoxy groups with linear high alcohols, ether alcohols, and α-hydroxyacids. The factors affecting the substitution ratios were determined.These siloxanes were copolymerized with methyl methacrylate (MMA), crosslinked with ethylene glycol dimethacrylate (EGDM) in order to examine the effect of substituted groups to the oxygen permeability coefficient (Pd) and surface free energy properties of the resultant copolymers.The substitution of the oxygen containing polar groups decreased the oxygen permeability due to the interactions between polar groups decreasing the free volume. However, these groups increased the polar component of surface free energy (γSP) and thus total surface free energy (γS). The hydrophilicity of the carbitol and 2-ethoxyethanol containing siloxane-MMA copolymers was found to be suitable for biomedical applications.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 151 (1987), S. 275-275 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 151 (1987), S. 95-101 
    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: Es wird ein Modell vorgeschlagen, nach dem die Dehnungsviskosität von Blends mit der Theorie des Freien Volumens so korreliert werden kann, daß die Dehnungsviskosität eines Blends für jede Zusammensetzung aus den Dehnungsviskositäten und dem Gewichtsbruch der Komponenten bestimmt werden kann. Die Voraussagen des Modells wurden an experimentellen Daten in vier Fällen überprüft.
    Notes: A model has been proposed to correlate the elongational viscosity of blends with the free volume theory so that the elongational viscosity of a blend at any composition can be determined from the elongational viscosity and the weight fractions of the individual components. The predictions of the model are compared with experimental data in four cases and found to give reasonable good agreement.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 152 (1987), S. 21-31 
    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: Ein Copolymeres aus 3,3′-Bisitaconimido-m,m′-diphenylsulfon und Methacrylsäure wurde in einer radikalischen Polymerisation hergestellt. Das Copolymere wurde charakterisiert und die Copolymerisationsparameter ermittelt. Die durch drei verschiedene Methoden erhaltenen Reaktivitätsverhältnisse stimmen gut überein und lassen auf ein alternierendes Copolymeres schließen. Der thermische Abbau des Bisitaconimidhomopolymeren und des Copolymeren wurden verglichen und das thermische Verhalten diskutiert. Die Aktivierungsenergien für die verschiedenen Stufen des thermischen Abbaus des Homo- und des Copolymeren wurden durch Coats-Redfarn-Diagramme ermittelt.
    Notes: A copolymer of 3,3′-bisitaconimido-m,m′-diphenyl sulfone and methacrylic acid was synthesized by free radical polymerization. The copolymer was characterized and the copolymerization parameters were evaluated. The reactivity ratios determined by three different methods were in good agreement and the values suggest an alternating copolymer. The thermal degradation of the bisitaconimide homopolymer and the copolymer were compared and the structural implications on the thermal behaviour are discussed. The activation energies for the different stages of thermal decomposition of both the homopolymer and the copolymer were evaluated from the Coats-Redfarn plots.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    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 parameters of solubility of HD PE and LD PE were used to calculate the Flory-Huggins-interaction parameter χ12 and, from this, the specific free mixing enthalpy ΔGm/V was determined according to Flory-Huggins for a system of these components. The diffusion rate of the PE molecules was estimated using the reptation model and the Einstein relation.The motive power of diffusion is proportional to the specific free mixing enthalpy. The results show that diffusion controlled segregation does not run in a HD PE/LD PE blend in the state of melt. This means that the morphology of polyethylene blends is only determined by mixing conditions in connection with the flow properties of components.
    Notes: Aus den Löslichkeitsparametern von HD PE und LD PE wurde ihr temperaturabhängiger Flory-Huggins-Wechselwirkungsparameter χ12 und daraus wiederum nach Flory-Huggins die spezifische freie Mischungsenthalpie ΔGm/V eines HD PE/LD PE-Systems berechnet. Unter Zuhilfenahme des „reptation“-Modells und der Einstein-Relation wurde die Diffusionsgeschwindigkeit der PE-Moleküle abgeschätzt. Die Triebkraft dieser Diffusion ist proportional der spezifischen freien Mischungsenthalphie. Die Ergebnisse zeigen, daß diffusionskontrollierte Entmischungserscheinungen in einer HD PE/LD PE-Mischung im Schmelzezustand nicht ablaufen. Das bedeutet, daß die Morphologie der Mischungen im Schmelzezustand nur durch die Mischbedingungen im Zusammenspiel mit den Fließeigenschaften der Komponenten festgelegt wird.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    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: Es wurde der Einfluß der Lösungsmittelzusammensetzung aus Toluol und n-Decanol auf die innere Struktur poröser Copolymerer untersucht.Eine Serie von Copolymeren mit jeweils 50 mol-% 1,4-Di(methacryloyloxymethyl)-naphthalin (1,4-DMN) und Divinylbenzol (DVB) wurde in Anwesenheit unterschiedlicher Anteile Toluol in der Mischung mit n-Decanol hergestellt. Um den Einfluß der Toluolkonzentration auf die innere Struktur der porösen Polymeren zu bestimmen, wurden die spezifische Oberfläche, die Porengrößenverteilung sowie die Polarität des Quellungsmittels untersucht.
    Notes: The influence of diluent composition on the internal structure of porous copolymers of 1,4-di(methacryloyloxymethyl)naphthalene (1,4-DMN) and divinylbenzene (DVB) was studied.A set of copolymers containing 0.5 mole fraction of 1,4-DMN and 0.5 mole fraction of DVB obtained in the presence of various amounts of toluene in the mixture with n-decanol was investigated. In order to establish the influence of toluene concentration on the internal structure of 1,4-DMN and DVB copolymers, surface areas, pore size distributions, and polarities of sorbents were investigated.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    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 solubility parameters of HD PE and LD PE above crystallization temperatures were determined on the basis of gas chromatographical retention data. The method of inverse gas chromatography was used. It showed that the solubility parameters of the types of polyethylene investigated are nearly equal within the margin of error. From the dependence of the solubility parameters on the temperature follows that the thermodynamical behaviour of the polyethylene components in mixtures is determined by their different free volumes.
    Notes: Für HD PE und LD PE wurden oberhalb der Kristallisationstemperaturen die Löslichkeitsparameter auf der Basis gaschromatographischer Retentionsdaten bestimmt. Als Meßverfahren wurde die Methode der Inversen Gaschromatographie angewendet. Es zeigte sich, daß die Löslichkeitsparameter der untersuchten Polyethylentypen innerhalb der Fehlergrenzen nahezu gleich sind. Aus der Beschreibung der Temperaturabhängigkeit der Löslichkeitsparameter folgt, daß das thermodynamische Verhalten der Polyethylenkomponenten in Mischungen durch ihre unterschiedlichen freien Volumina determiniert ist.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 152 (1987), S. 41-53 
    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: Die schwachvernetzten Polyurethane mit Allophanat- und C—C - Bindungen wurden durch die Reaktion von 4,4′-Diphenylmethandiisocyanat mit einer Poly(ethylenadipat)/Poly(ethylenmaleat)-Mischung sowie mit einer Mischung aus Terephthal-Adipinsäure-Copolyesterdiol und niedermolekularen Diolen hergestellt.Die Ergebnisse der isothermen und dynamischen thermischen Analyse in inerter Atmosphäre zeigen, daß die thermische Stabilität der Polyurethane von der Vernetzungsdichte und der chemischen Struktur der Vernetzungsbindungen und der Hart-Segmente unabhängig ist.
    Notes: Polyurethanes slightly crosslinked with allophanate and C—C linkages have been prepared by reaction of 4,4′-diphenylmethane diisocyanate with poly(ethylene adipate) and poly(ethylene maleate) as well as with terephthalic-adipic copolyesterdiol and some low molecular diols.Data obtained from isothermal and dynamic thermogravimetric analysis carried out in an inert atmosphere indicate that the thermal stability of polyurethanes is independent on the crosslinking density and the structural characteristics of crosslinks and hard segments.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 152 (1987), S. 79-91 
    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: Diese Untersuchung befaßt sich mit einigen kinetischen Merkmalen der Reaktion von n-Butylisocyanat mit Polyvinylalkohol ohne jeden Katalysator und unter Verwendung von Triethylendiamin als Katalysator. Die Struktur der resultierenden Polymeren wurde mit Hilfe der IR-, 1H-, und 13C-NMR-Spektroskopie und chemischer Analyse ermittelt. Es wurden Vinylalkohol-Vinylbutylurethancopolymere (VAL-VBU) erhalten. Es ergab sich eine lineare Abhängigkeit der Reaktionsgeschwindigkeit von Polymer-, n-Butylisocyanat- und Triethylendiaminkonzentration. Die Reaktionsgeschwindigkeitskonstante nimmt mit zunehmender Reaktionszeit ab. Das kann mit der sterischen Hinderung durch die Urethangruppen, die entlang der Polymerkette eingebaut sind, erklärt werden. Die Aktivierungsenergie ergab sich zu 49,9 kJ/mol. Eine kinetische Untersuchung der homogenen Hydrolyse von VAL-VBU-Copolymeren wurde durchgefilhrt als Funktion der Basenkonzentration, der Temperatur und des VBU Gehalts. Es zeigte sich, daß die homogene Hydrolyse als Reaktion 1 . Ordnung verliluft, sowohl im Hinblick auf die Hydroxylionen als auch auf den VBU-Gehalt. Die Aktivierungsenergie filr die basenkatalysierte Hydrolyse betragt 79,3 kJ/mol. Die heterogene Hydrolyse von VAL-VBU-Copolymeren im basischen Medium zeigte, daß keine Hydrolyse unter diesen Bedingungen stattfand.
    Notes: This study is concerned with some kinetic features of the reaction of n-butyl isocyanate with poly(vinyl alcohol) without any catalyst and using triethylene diamine as catalyst. The structure of the resulting polymers was determined by means of IR, 1H- and 13C-NMR spectroscopy as well as by chemical analysis. Vinyl alcohol-vinyl butyl urethane (VAL-VBU) copolymers were obtained. It has been found a linear dependence of reaction rate on polymer, n-butyl isocyanate, and triethylene diamine concentrations. Reaction rate constant decreases as reaction time increases. It can be explained by steric hindrance phenomena due to urethane groups incorporated along the polymeric chain. The activation energy was found to be 49.9 kJ/mol. A kinetic study of the homogeneous hydrolysis of VAL-VBU copolymers has been made as a function of the base concentration, the temperature, and the VBU content. The homogeneous hydrolysis was found to be first order with respect to both hydroxyl ion and VBU contents. The activation energy for the base catalyzed homogeneous hydrolysis was found to be 79.3 kJ/mol. The heterogeneous hydrolysis of VAL-VBU copolymers in basic medium showed that no hydrolysis takes place under the conditions employed.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 152 (1987), S. 107-119 
    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: Ein mit Ruß gefülltes 50/50 NR/SBR-Blend (Naturkautschuk/Styrol-Butadien-Copolymer) wurde unter Verwendung verschiedener konventioneller Vernetzungssysteme, die durch unterschiedliche Schwefel- und Beschleunigeranteile gekennzeichnet sind, vulkanisiert. Die Vulkanisationscharakteristiken und die Eigenschaften der Vulkanisate wurden verglichen. Das Ausmaß und die Qualität der Vernetzungsstellen wurden für jeden Fall durch chemische Testmethoden ermittelt, um sie mit den Vulkanisateigenschaften zu vergleichen.
    Notes: A carbon black filled 50/50 natural rubber (NR)/styrene-butadiene rubber (SBR) blend is vulcanized using several conventional curing systems designed by varying the amounts of sulphur and accelerator. The cure characteristics and the properties of the vulcanizates are compared. The quantity and quality of crosslinks in each case are evaluated by chemical probes to correlate them with the vulcanizate properties.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    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: Die Arbeit stellt eine Erweiterung der vorhergehenden Untersuchungen hinsichtlich synthetischer Polymerer mit sehr großen Molekularmassen dar. Die Grenzviskositäten und die Viskositätskonstanten von Poly(isobutylmethacrylat) wurden mit den Methoden von Huggins, Kraemer, Martin, Schulz-Blaschke und Fedors in CCl4 und C6H6 bei 25°C erhalten. Es wurde beobachtet, daß die Methode von Fedors nicht sehr sensibel ist bei den möglichen Fehlern, die bei der Bestimmung der relativen Viskositäten in konzentrierten Bereichen auftreten. Diese Methode führt zu Grenzviskositäten, die nahe den mittleren Werten liegen, die mit den anderen fünf Methoden und der Sakai-Mitteilung erhalten wurden. Außerdem wurden die Umwandlungskonzentrationen, die die verdünnt-halbverdünnten Bereiche trennen, sowie die Mark-Houwink-Konstanten bestimmt.
    Notes: The paper extends previous studies on ultrahigh molecular weight synthetic polymers. The intrinsic viscosities and the viscosity constants of poly(isobutyl methacrylate) fractions were obtained by the methods of Huggins, Kraemer, Martin, Schulz-Blaschke, and Fedors in CCl4 and C6H6 at 25°C. It was observed that the method of Fedors is not very sensitive to the possible errors appearing in estimating the relative viscosities in higher concentration domains. This method yields intrinsic viscosity values close to the mean values obtained from the other five methods and to the values calculated according to the averaging procedure suggested by Sakai. The transition concentrations separating the concentration domains (diluted-semidiluted) and the Mark-Houwink constants were obtained.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 152 (1987), S. 133-147 
    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: Die strahleninduzierten Pfropfungen der hydrophoben Monomeren Styrol und Methylmethacrylat sowohl auf gefärbtem Teppich als auch auf gefärbter und ungefärbter Wolle werden ausgeführt. Betont wird die Notwendigkeit des Quellens zur Erzielung einer merkbaren Pfropfausbeute. Es wurde gefunden, daß die Pfropfungsgeschwindigkeit für die gefärbte Wolle wie auch für den Teppich kleiner ist als für die ungefärbte Wolle. Diese Ergebnisse werden erklärt mit der abschirmenden Wirkung der aromatischen Farbstoffmolekülteile. Bei geringen Monomerkonzentrationen wurde ein Umsatz von 97% bezogen auf die eingesetzte Monomermenge gefunden, da die als Nebenreaktion ablaufende Homopolymerisation in Gegenwart von Radikalabfängern fast vernachlässigbar ist. Eine angemessene Hydrophobie wurde erreicht bei mit ca. 80% Styrol und ca. 150% Methylmethacrylat gepfropfter Wolle.
    Notes: Radiation initiated grafting of hydrophobic monomers styrene and methyl methacrylate onto wool (dyed and undyed) and dyed carpet has been carried out. The importance of swelling in obtaining appreciable amounts of grafting has been stressed. The rate of grafting with dyed wool and carpet is found to be less than for undyed wool and the results are explained on the basis of protection offered by aromatic moieties of the dye. Efficiency of monomer utilization has been found to be as high as 98% at low concentrations of the monomer since the accompanying (parasitic) homopolymerisation is almost negligible in the presence of scavengers. Reasonable hydrophobicity is achieved in ca. 80% styrene grafted and ca. 150% methyl methacrylate grafted wool.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 155 (1987), S. 163-175 
    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 flow behavior of bicomponent polymer blends of chlorinated polyethylene (PEC) and poly(methyl methacrylate) (PMMA) is presented in the form of flow curves. The relations between the rheological measurements and the morphology are discussed. The blends (PEC/PMMA, chlorinated up to 40 wt.-%) show the characteristic behavior of incompatible systems, some of them with a second highly dispersed phase. In addition a system of PE/PMMA is examined, the PE being the raw material of the PEC. The influence of the chlorination on flow behavior and the biphase structure is obvious.
    Notes: Das Fließverhalten von Mischungen aus chloriertem Polyethylen (PEC) und Polymethylmethacrylat (PMMA) wird in Form von Fließkurven dargestellt. Die Ergebnisse der rheologischen Messungen werden anhand der sich ausbildenden Morphologie diskutiert. Es zeigt sich, daß die untersuchten Mischungen aus PEC/PMMA mit Chlorierungsgraden bis 40 Gew.-% Cl das charakteristische Verhalten von unverträglichen (2-phasigen) Mischungen mit teilweise fein dispergierter zweiter Phase liefern. Vergleichend wird die Stoffkombination PE/PMMA betrachtet, wobei die PE-Sorten jeweils die unchlorierten Ausgangsprodukte darstellen. Der Einfluß der Chlorierung auf das Fließverhalten und die zweiphasige Struktur ist deutlich festzustellen.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 155 (1987), S. 191-197 
    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: Polystyrol wurde in Lösung mit SbCl3 als Katalysator und 10-Trifluoracetylphenothiazin als Cokatalysator chloriert. Dabei wurde ein Polymeres erhalten, das durch die Formel . beschrieben werden kann. Die aromatische Substitutionsreaktion (x 〉 1) erfolgt vorwiegend and der para-Position; das Verhältnis der para- zur ortho-Chlorierung beträgt 10 - 12. Die Grenzviskositätszahl bei 30°C einer toluolischen Polymerlösung nimmt mit dem Chlorgehalt x des Polymeren ab. Der Brechungsindex nD wächst mit x. Der nD - Wert eines Polymeren mit 25,05 Gew.-% Chlor (x ≃ 1) beträgt 1,6041.
    Notes: Polystyrene has been chlorinated in the liquid phase by SbCl3 catalyst combined with 10-trifluoroacetylphenothiazine to afford a polymer, which is represented by the formula . The aromatic substitution reaction (x 〉 1) occurs predominantly at the p-position, the ratio of p- to o-chlorination being 10-12. The intrinsic viscosity of the toluene solution at 30°C decreases with content of chlorine, x. The refractive index, nD, increases with x. The nD value of a 25.05% chlorine-containing polymer (x ≃ 1) is 1.6041.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    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: Die Wechselwirkungen des Polymergerüsts und die Komplexbildung mit einer Reihe von Schwermetallen wurde für die Methylthioharnstoff als Liganden tragenden Basispolymeren Poly(ethylenimin), Poly(vinylpyrrolidinon) und Poly(acrylamid) in Abhängigkeit vom pH-Wert untersucht.Retentionsstudien in wässriger Lösung unter Verwendung von Membranfiltration wurden zur Bewertung der Wechselwirkungen zwischen Metallionen und Makromolekülen in Abhängigkeit vom pH-Wert herangezogen. Es wurde für die Ionen Na, Co, Ni, Cu, Zn, Cd, Hg, Fe gezeigt, daß die Wechselwirkung sowohl von der Art des Polymergerüsts als auch vom pH abhängt. Während die Retentionswerte von Copolymeren auf der Basis von Poly(ethylenimin) nur schwach vom pH beeinflußt wurden, zeigten die beiden anderen untersuchten Copolymeren eine starke Abhlngigkeit für die einzelnen Metalle. Es wurde eine vorherrschende Wirkung des funktionellen Liganden-Comonomeren hinsichtlich der Wechselwirkung im Vergleich zum Basismonomeren füur den größten Teil der untersuchten Metallionen gefunden.
    Notes: The interactions of the polymeric backbone and complex formation with a series of metals were investigated for poly(ethyleneimine), poly(vinylpyrrolidinone), and poly-(acrylamide) as basis polymers with methylthiourea as ligand. Retention studies by application of membrane filtration of aqueous solutions were used for the evaluation of interaction between the metal ions and macromolecules as function of pH. It was shown for the Na, Co, Ni, Cu, Zn, Cd, Hg, Fe ions that the interaction depends both on the type of polymer backbone and the pH.Whereas for poly(ethyleneimine)-based copolymers the retention data were influenced only slightly by pH, the two other copolymers investigated showed a strong pH dependency for the individual metals. A dominating effect of the functional ligand comonomer in terms of the interaction over the basis monomer was observed for the majority of metal ions investigated.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    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: Für die in einer pseudostationären Laserpuls-induzierten Photopolymerization entstehenden Polymeren werden Gleichungen für die Zahlen- und den Masenmittelwert der Polymerisationsgrade abgeleitet. Der Kettenabbruch kann dabei, bei vernachlässigbarer Kettenübertragun, in einer Disproportionierung oder einer Rekombination bestehen. Die Analyse der bei verschiedenen Pulsabständen resultierenden Polymerisationsgrade ermöglicht die Bestimmung der Wachstumskonstanten (kp) und des Produkts kt ρ (kt = Geschwindigkeitskonstante des bimolekularen Kettenabbruchs, ρ = Konzentration der pro Laserblitz produzierten Primärradikale). Da überdies k2/kt%/& aus der (pseudostätionaren) Polymerisationsgeschwindigkeit und dem Massenmittel-Polymerisationsgrad des im selben Experiment gebildeten Polymeren berechnet werden kann, ist es, zumindest im Prinzip, möglich, eine vollstähdige Auflösung in die individuellen GröBen kp, kt und ρ zu erreichen. Anhand eines Beispiels läßt sich zeigen, daß die auf diesem Weg für die Styrolpolymerisation bei 25°C gewonnenen Daten gut mit jenen übereinstimmen, die mittels anderer Methoden erhalten wurden.
    Notes: Equations are derived for the number average and the weight average degrees of polymerization for the polymer forming in a laser-initiated photo-polymerization under pseudostationary conditions when termination occurs by disproportionation or recombination and if chain transfer is negligible. Analysis of the degrees of polymerization at various pulse separations leads to information on the rate coefficient of propagation (kp) and on the product kt ρ (kt = rate coefficient of bimolecular chain termination, ρ = concentration of primary radicals produced in each flash). As kp2/kt may be evaluated from the rate and the weight average degree of polymerization P̄w of a single pseudostationary experiment, at least in principle, a complete resolution into individual constants may be achieved. It is demonstrated in an example that the data obtained in this way for the polymerization of styrene at 25°C are well consistent with those originating from other methods.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 155 (1987), S. 199-200 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 27 (1987), S. 1021-1034 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: Equations are derived that relate the orientation of “pseudo-affine” reoriented structural units after a biaxial deformation to the degrees and the directions of the effective drawings. The connection between these drawing parameters and those externally applied is analyzed in detail. It is shown how a comparison of these two sets of drawing parameters allows conclusions regarding the distribution throughout the material of the stresses that cause the deformation, the inhomogeneity of the deformation, and the role of non-orienting flow during deformation. In particular, the orientation of biaxially drawn poly(ethylene terephthalate) films is investigated, and it is shown what general information can be obtained on the deformation behavior of this material on the basis of these considerations.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 27 (1987), S. 1059-1068 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: Scale-up from small laboratory size extruders to large production size extruders is a procedure of great practical importance. Many scale-up rules and theories have been proposed in the past, however it is not always clear how the different scale-up methods will affect extruder performance. A basic analysis of scale-up in plasticating single screw extruders is developed from which the effect of a certain scale-up strategy on extrusion performance can be evaluated in terms of solids conveying, melting, melt conveying, mixing, residence time, heat transfer, power consumption, and specific energy consumption. Various existing scale-up theories are evaluated and compared using the basic analysis. A number of existing scale-up theories have some significant drawbacks, in particular with non-constant specific energy consumption and imbalance between melting rate and pumping rate. Conditions that are desirable to achieve in scale-up are enumerated and ranked in terms of importance. This leads to two new scale-up methods that result in constant mechanical specific energy consumption and high throughput rates. The first scale-up method keeps the specific surface area constant. This scale-up should work well for high values of the Brinkman number. However, at low values of the Brinkman number, the melting rate may be insufficient. The second scale-up method keeps the melting rate at low Brinkman number equal to the pumping rate and, thus, should be useful in cases where the first scale-up method cannot be used.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 27 (1987) 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 27 (1987), S. 1128-1136 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: The plane strain fracture toughness and fracture mechanisms of several tough engineering plastics have been studied and compared with poly(methyl methacrylate) (PMMA), a relatively brittle polymer. The tough polymers all are observed to form a multiple craze zone at the crack tip, which is shown to be the primary source of plane strain fracture toughness in these materials. The multiple craze zone is retained during slow crack growth but is metastable, and at a critical stress intensity and associated crack velocity, the system passes through a transition to a greatly accelerated single craze mode of unstable propagation.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 27 (1987), S. 1148-1155 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: The optical properties of bisphenol-A polycarbonate resin as described by the complex index of refraction, N = n - ik, are derived by Kramers-Kronig analysis of experimental absorption and reflectance data obtained in the range 40μm ≥ λ ≥ 105 nm. Electronic absorption processes in polycarbonate are characterized by two broad absorption peaks centered at ∼200 and ∼100 nm.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 27 (1987), S. 1182-1186 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: Three-layer coextruded blown (either blend or composite) films, made of low-density polyethylene and linear lowdensity polyethylene (1:1 ratio) of identical density, were compared. The tensile properties of both systems are nearly as high as those of the linear polyethylene while high strain rate properties including impact strength and tear resistance of the composite film are superior. Some structural insight was obtained by thermal analysis and thermoelastic measurements. Structure property relationships are discussed in light of the unique behavior, structure, and morphology of linear low-density polyethylene. The two polyethylenes are only compatible to a rather limited extent mainly affecting their blend behavior. However, a strong mutual reinforcement effect was observed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 27 (1987), S. 1203-1208 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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 Viton copolymer containing vinylidene fluoride (VF2) and hexafluoropropylene (HFP), and a terpolymer containing VF2, HFP, and tetrafluoroethylene (TFE) were cross linked using varying amounts of Bisphenol AF to yield two series of fluoroelastomer networks, Stress-strain isotherms in elongation were determined for these samples at several temperatures and at two degrees of swelling with phenyl acetate. Strain-induced crystallization was observed, as evidenced by upturns in the isotherms at high elongations. It appears to be more pronounced in the terpolymer samples, presumably because the TFE units not only can crystallize themselves, but can co-crystallize with the VF2 units. The crystallization was found to persist upon moderate increase in temperature, but was suppressed when the networks were swollen, Thermoelastic (force-temperature) measurements were used to obtain values of the fraction fe/f of the elastic force that is due to energetic effects. Negative values were obtained for both types of samples and, in the case of two samples studied in detail, their magnitudes increased with increase in elongation. The magnitudes were larger and the increases more pronounced in the case of the terpolymer networks, as would be expected from a greater tendency for straininduced crystallization.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 27 (1987), S. 1221-1228 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: The transesterification reaction of molten ethylene and vinyl alcohol copolymers (EVA), in presence of paraffinic alcohols and basic catalysts, leads to high conversion of the ester groups to secondary alcohol in both discontinuous and continuous processing equipment. Various kinds of alcohols and two different catalysts were used. Sodium methoxide is a powerful catalyst for the equilibrated transesterification reaction, but we also observed side reactions, such as cross-linking with low-molecular-weight alcohols and hydrolysis of the catalyst followed by partial saponification of the EVA. Kinetic studies were performed in the presence of dibutyltin dilaurate, an efficient catalyst without any side reactions. The solubility of the main alcohol reagents was verified by diffusion measurements. The general reaction scheme and the related kinetics, corresponding to a homogeneous system, lead to a fair evaluation of the rate constants.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 27 (1987), S. 1252-1257 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: The mechanical properties of polyurethane-unsaturated polyester interpenetrating polymer networks (IPNs) that were prepared by reaction injection molding (RIM) process were measured with variations In composition, cross-link density, and relative reaction rate. From dynamic mechanical analysis (DMA), it was found that the two component polymers had a good compatibility over the whole composition range. The tensile strengths of the blends were greater than those of the pure components and had a maximum value at 50/50 composition. The modulus of elasticity and surface hardness decreased and the impact strength increased as the polyurethane content was increased, but the changes were not high at low polyurethane content, below 50%. For higher cross-link density, the compatibility was enhanced and the mechanical properties were improved. When the reaction rates of the components were different, some extent of phase separation was found in DMA and the properties were affected adversely.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 349-355 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: cis- and trans-PolyacetyleneSystematic name: (Z)- and (E)-poly(viny1ene). films prepared by a rare-earth coordination catalyst were doped with ferric chloride in nitromethane solution. The doped polyacetylene films [CH(FeCl4)y]x exhibit high electrical conductivities which change very little when stored in dry air. Infra-red absorption bands at 900 cm-1, 1300 cm-1 and 1400 cm-1 are typical for cis-and trans-polyacetylenes slightly doped with FeCl3. In the samples with dopant mole fractions y 〈 0,02, two superimposed ESR signals with different g values are observed: one very narrow, the other one extraordinarily broad. 57Fe-Mössbauer effect measurements reveal that Fe(II) and Fe(III) species coexist in freshly doped cis-polyacetylene, appearing in the form of FeCl2 · nH2O and FeCl-4, respectively. Fe(II) species do not interact with the polyacetylene chain; they exist at a site separated from Fe(III) species.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 599-606 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The bilayer structure of the phospholipid L-α-dimyristoylphosphatidylethanolamine (DMPE) was determined by X-ray diffraction fiber methods. This study was carried out on oriented films at different degrees of hydration at room temperature (about 19°C). DMPE molecules pack very closely with their two hydrocarbon chains almost fully extended and coplanar with their polar group, which lies perpendicular to the chains. It was found that the unit cell dimensions of DMPE did not vary appreciably between 0 and 86% relative humidity nor did its longest axis with an excess of water. The methods and techniques used to prepare the specimens and to solve the structure are described.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 593-598 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polyacrylates of monomethoxypoly(ethylene oxide)Systematic name for MePEO: α-hydro-ω-methoxypoly(oxyethylene). (MePEO) were prepared by grafting MePEO on prepolymerized acryloyl chloride polymers of different molecular weights. Copolymers with carboxyl groups were also prepared by the addition of both water and MePEO. The polymers spontaneously form irreversible gels in water as soon as the degree of polymerization exceeds a certain limit. This gel formation confirms preceding results on similar polymers obtained by polymerization of MePEO acrylate and methacrylate macromonomers. It is concluded that the gelification phenomenon is not due to chemical cross-linking but rather to the presence of a high density of strongly interacting grafts of PEO on the polymer backbone. This new type of self-gelling system is considered to be of special interest.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 651-663 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The transition from the nematic melt to the solid state in a rigid rod-like copolymer was found to be characterized by unusual thermodynamic and kinetic properties. The transition occurred with negligible volume changes. The enthalpy and the entropy of the transition were found to be lower by at least one order of magnitude in comparison to the values usually observed for a crystal to nematic transition. The ordered solid state displays a glass transition and its structure is characterized by high symmetry, i.e., an orthorhombic one. Dielectric relaxation studies, investigations on the plastic flow properties of the solid state and studies on the dynamical mechanical properties revealed a high degree of rotational freedom already at room temperature in the solid state. These experimental findings led us to the conclusion that the solid state displays a three-dimensional positional long range order but is rotationally disordered with respect to rotations about the long axes of the rod-like molecules. The structure is similar to those of plastic crystals known for spherical molecules such as cyclopentane, or to smectic E modifications known for rod-like molecules. Also the properties reported above for the rod-like copolymers resemble those reported in the literature for plastic crystals.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Guanylate-rich oligodeoxyribonucleotides d(G4T4), d(T4G4), d(T4G4T4), d(G4T4G4), and d(T4G4T4G4) were synthesized in amounts up to 350 mg using the triester method in solution. These oligonucleotides correspond to fragments of the terminal of macronuclear DNA from hypotrichous ciliates. The protected oligonucleotides were obtained by block-condensation of protected 5′-hydroxyl and 3′-phosphate derivatives. Mixtures of 2,4,6-triisopropylbenzenesulfonyl chloride/N-methylimidazole or 2,4,6-trimethylbenzenesulfonyl chloride/N-methylimidazole were used as condensating agents. Different concepts of protecting the nucleotides were investigated and it was found that yields and purities of the resulting oligonucleotides do not depend essentially on the employed concept. The 36mer d(G4T4G4T4G4T4G4T4G4) was obtained by enzymatic phosphorylation of aliquots of the dodecamers d(G4T4G4) and d(T4G4T4), followed by ligation with T4 DNA ligase.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 1367-1373 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Vinyl monomers containing blocked isocyanato groups were prepared in one step, by blocking the isocyanato group of 2-isocyanatoethyl methacrylate with phenol, propanone oxime, butanone oxime, benzophenone oxime or ε-caprolactam, or in two steps, by blocking one of the two isocyanato groups of 4-methyl-1,3-phenylene diisocyanate with phenol or ε-caprolactam and the second group with 2-hydroxyethyl methacrylate. The 1H NMR and the IR spectra of these monomers are discussed.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 1391-1401 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The miscibility of poly(1,1-difluoroethylene) (1) with poly(N-vinyl-2-pyrrolidone) poly(N-methyl-N-vinylacetamide) and poly(N,N-dimethylacrylamide), containing tert-amido groups, was investigated by differential scanning calorimetry. Amorphous homogeneous blends were obtained whenever the weight fractions of polymer 1 is less than 0,7. The dependence of the single glass transition temperature (Tg) versus composition may be readily analyzed either through the Gordon-Taylor equation (high values of the k parameter, suggesting strong specific interactions between the homopolymers) or by means of the Couchman relation (no adjustable parameter). The broadening of the glass transition range and the variation of the increment of specific heat at Tg for the blends are discussed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 1425-1430 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The electroconductive polymer poly[(2,2′-dithienyl)-5,5′-diylvinylene] (1) was prepared by both electrochemical and chemical methods starting from trans-di(2-thienyl)ethylene (2). The electrochemically prepared material showed electrical conductivities of up to 40 Ω-1 · cm-1; the neutral, chemically prepared polymer was droped with iodine or arsenic pentafluoride but the conductivities were low. The experimental procedures are described and an interpretation of the results is given.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 1447-1463 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Methods for the preparation of macroporous poly(4-vinylpyridine/divinylbenzene) resins with very different structures are described and the process of polymerization is discussed. The resins were prepared by suspension polymerization. The divinylbenzene content was varied between 8 and 25 mol-% and dioctyl phthalate, heptane, toluene, and mixtures of these solvents have been used as porogenic agents. The morphology of the resins was determined by mercury porosimetry, BET surface measurements, and electron scanning microscopy. By the use of aliphatic porogenic agents high pore diameters up to 9000 Å and surface areas of at least 17 m2/g resin were found whereas by the use of aromatic solvents like toluene resins of low pore size and surface areas up to 88 m2/g were obtained.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 1861-1873 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Copolymerizations of glycolide with L,L-dilactide were conducted in chloroform, 1,2-dichloroethane and nitrobenzene. Chlorosulfonic acid, triflic acid, boron trifluoride, triethyloxonium tetrafluoroborate, but mainly methyl triflate, were used as initiators. 50°C was found to be an optimum reaction temperature, because higher temperatures resulted in dark coloured products of low viscosities. The composition of the copolyesters was determined by 1H NMR spectroscopy and the sequences by 13C NMR spectroscopy. Dyad splitting of the carbonyl signals allowed an accurate calculation of average block lengths. Under all circumstances glycolide showed a higher rate of incorporation, and truely random sequences were never obtained. However, the relative reactivities of both monomers largely depend on the nature of the initiator. The best results with regard to random sequences were obtained in 1,2-dichloroethane with methyl triflate (rG = 10,5 and rL = 0,9) and with triflic acid (rG = 14,0 and rL = 0,5). DSC measurements revealed that most samples possess crystalline domains of polyglycolide blocks. Nonetheless, many samples are soluble in hexafluoro-2-propanol and the amorphous samples also in dichloromethane or chloroform.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: 2-Bromoethoxycarbonyl modified amino acids were reacted with pyridine, 4-picoline and poly(4-vinylpyridine) to yield the corresponding 2-(N-pyridinio)ethoxycarbonyl derivatives as water-soluble amino-protecting groups. The kinetics and activation energies of basicly induced cleavage of the amino acids were investigated by 1H NMR spectroscopy in a D2O/NaOD medium. The polymeric salts were found to be more reactive than the low molecular weight pyridinium bromides because of electrostatic polymeric effects. Additionally, the kinetic measurements confirmed a E1cB mechanism for the cleavage of the urethane function. The formation of peptide bonds was performed in the case of poly[2-(N-4-vinylpyridinioethoxycarbonyl)]-protected amino acids in aqueous medium by water-soluble carbodiimides.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 2071-2082 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A poly(allylamine) {poly[1-(aminomethyl)ethylene]} (2) containing covalently bound β-cyclodextrin (CD) residues (3) was synthesized. The inclusion ability of CD was enhanced in this polymer 3. A pronounced catalytic acceleration of the hydrolysis of p- and m-nitrophenyl acetate by 3 as compared with that of 2 indicates the cooperative effect of CD and amino groups on the polymer chains.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 35-45 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: 2,3-Epoxypropyl esters were obtained in two steps from carboxylic acids or in one step from their alkali salts by reaction with 1-chloro-2,3-epoxypropane or from the acid chloride with 2,3-epoxy-1-propanol. The kinetic parameters of these reactions were studied with acetic acid and sodium acetate to evaluate the optimal conditions for the synthesis of these esters with the intention to apply them to polymers containing carboxylic groups.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Styrene/1-hexene copolymers of different chemical composition were prepared with a classical isospecific Ziegler-Natta catalyst, TiCl3(H)-AlEt3. Their structure and the distribution of the monomeric unites was analyzed by GPC double detection and 1H and 13C NMR. The chemical arrangement of isolated and blocked styrene monomeric units between sequences of hexene monomeric units was also investigated. 13C chemical shifts of carbon atoms in the copolymers and in addition in model molecules of the two modes of styrene addition indicate that styrene insertion into carbon-metal bonds of the catalyst proceeds according to a primary mode. Mechanistic implications of these results are discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 455-455 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polymeric phosphonium ion species having different content of phosphonium units (4a and 4b) were prepared from poly[(P-phenyl)trimethylenephosphine] (3). Phase-transfer catalysis of 4 was examined by means of a typical SN2 reaction (1) in a bi-phase system. The apparent rate constant (kobs) was determined, its magnitude being smaller by about one order than that of the corresponding monomeric phosphonium ion 5. Crosslinked polymeric phosphonium ion species were coated on powdery alumina and used as a phase-transfer catalyst for reaction (1) in a triphase system. Due to the inhomogeneous reaction, the kobs value was much smaller (1/5) than that in presence of 4.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A new monomer, 4,5-dihydro-2-[2-(9-anthryl)ethyl]-1,3-oxazole (5) was synthesized and polymerized by cationic ring-opening isomerization. The polymerization was carried out in bulk or in solution, using methyl tosylate, ethylene ditosylate and α-tosyl-ω-tosyloxypoly(oxyethylene) [poly(ethylene oxide)ditosylate] as initiators. The polymers were characterized by IR, 1H NMR and UV spectroscopy.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 527-536 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The theory of slow-initiation-no-termination polymerization has been extended to take account of transfer by added or adventitious transfer agents (T), giving equations relating the number-average molecular weight (M̄n) to the ratios of concentrations of transfer agent to monomer ([T]0/[M]0) and of transfer to propagation rate constants (ktr/kp). The equations are shown to give a fair description of the M̄n values found in the polymerization of butyl cyanoacrylate by pyridine and by tetrabutylammonium acetate in presence of known concentrations of cyanoacetic, chloroacetic and acetic acids. Approximate values are yielded for the rate constant ratios, viz. 102(ktr/kp) ≈ 15,5 and 0,3, respectively (in tetrahydrofuran at 20°C). Conversely, the theory is shown to explain variations in M̄n values found in polymerizations of five different samples of this monomer, permitting characterization of the unknown concentrations of transfer-causing impurity.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 155-170 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The steady state of reversible polymer-analogous reactions is simulated by Monte Carlo methods. Two types of sets of relative rate constants were investigated, first, K1 = K2 = K3, K1 · K3 = (K2)2, and second, K1 ≠ K2, K1 ≠ K3, K2 ≠ K3, K1 · K3 = (K2)2. For both cases a detailed balance was found. The sequence probabilities depend on dimensionless relative rate constants Kn only, while the rates of sequence flow depend on reaction probabilities p and ordinary rate constants k. For the first case, the sequence probabilities obey a Bernoullian statistics, while for the second case a first-order Markov statistics is found.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 189-199 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In order to evaluate copolymerization rates from dilatometric measurements, the relationship between volume contraction and conversion (dilatometric constant) must be investigated. This can be done gravimetrically or by means of density measurements. In cases where one of the monomers is not able to homopolymerize, both methods lead to different values. Equations necessary for this evaluation were derived and verified in the systems diethyl maleate-methyl methacrylate and diethyl maleate-styrene. In some cases, the dependence of the dilatometric constant on feed composition may be predicted taking into account the contributions to volume contraction of the different bond types present in the copolymer. An expression was derived for describing this dependence in cases where one of the monomers does not homopolymerize. Its validity for the system diethyl maleate-styrene was experimentally verified.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 217-226 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A phenomenological model is proposed which considers the polymer as an aggregate of units. The units are composed of two distinct phases  -  amorphous and crystalline. The thermal conductivity of a unit is calculated in terms of those of its constituents. In the undrawn state these units are distributed randomly, and the isotropic thermal conductivity of the bulk results. The development of strong anisotropy in thermal conductivity is explained in terms of the preferred orientation of these units. The structural features of this model are similar to those employed for the interpretation of the mechanical properties. The change in orientation of the units was deduced from the experimental data of birefringence. Finally, the results obtained from the composite model for several semicrystalline polymers are compared with the experimental data and other existing calculations. The model is found to give a fair overall description of the thermal conductivity in the cases of polypropylene, polyoxymethylene, low and high density polyethylene, and polychlorotrifluoroethylene.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 227-238 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The study concerns the potentiometric behaviour of statistical copolymers of 2-dimethylaminoethyl methacrylate with 2-hydroxyethyl methacrylate, acrylamide, methacrylamide, 2-methacryloyloxyethyltrimethylammonium methylsulfate, and of copolymers arising by the partial quaternization of poly(2-dimethylaminoethyl methacrylate) with methyl iodide in various water-ethanolic solutions. The potentiometric properties of poly(4-dimethylaminobutyl methacrylate) and poly(6-dimethylaminohexyl methacrylate) are also reported. The course of modified titration curves and the differences between pK0 values of copolymers and pK values of low-molecular weight model compounds are discussed. Side chains of copolymers of 2-dimethylaminoethyl methacrylate have a cyclic conformation (similarly to the homopolymer); the carbonyl and amine group interact with each other. Copolymers formed by the partial quaternization of poly(2-dimethylaminoethyl methacrylate) with methyl iodide in a water-ethanolic medium (Menshutkin's reaction) have a block structure, which suggests a zip mechanism of the quaternization reaction.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 3060-3060 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 749-762 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Biological materials, rich in hemicelluloses (birch and pine wood, wheat straw and rice hulls) were disintegrated batchwise in a flow reactor with pure water at elevated temperatures and pressures. The resulting extractives and residual fibre compounds were characterized. Because of rapid removal of carbohydrate based extractives from the hot reaction zone, the degradation of pentosans and hexosans to furfural and hydroxymethylfurfural could be limited to only a small amount. Contrary to normal prehydrolysis conditions employing a sealed batch reactor, temperatures of 190 to 210°C and residence times of goods of 60 min are the optimum. Thus, hemicelluloses are dissolved and isolated with up to more than 90% yield. At temperatures above 225°C severe destruction of hemicelluloses and solvolysis of cellulose starts. Depending on disintegration temperatures, pentosan average molecular weights (M̄w) vary in case of birch wood between 3800 at 150°C and 900 at 225°C. The content of monomers rises with temperature and reaches a maximum of 45% at 225°C. DPw of residual cellulose is also temperature dependent and varies in case of birch wood and wheat straw between 1500 and 450. Lignin, which is mostly not dissolved, can be removed almost quantitatively by further treatment of the residue with ethanol/water at 250°C, thus allowing the isolation of relatively pure cellulose.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 783-789 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Anion exchange and ring-opening reactions of cyclic quaternary ammonium salt end groups of poly(tetrahydrofuran) [poly(THF)] were studied. The counter anion exchange reaction of the quaternary ammonium triflate to the sulfonate or to the carboxylate, was found to take place by precipitation of the starting poly(THF) prepolymer from an aqueous solution containing the corresponding sodium salt. The azetidinium salt 1 was found to undergo ring opening reaction with its carboxylate counter ion at ambient temperature, whereas the pyrrolidinium salt 2 needs heating up to 100°C. The ring-opening reactivities of the cyclic ammonium salts of poly(THF) chain ends were compared with those of model systems.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 811-820 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The synthesis of the liquid crystalline polysiloxanes 8a-c is reported. In these polymers carbazolyl groups are incorporated in the mesogenic units. 8a-c were prepared from the Schiff's bases 7a-c and poly(hydrogenmethylsiloxane) in a polymer analogous reaction. The liquid crystalline polymers were characterized by DSC and polarizing microscopy. The Schiff's bases 7a-c are nematic, whereas the polysiloxanes 8a-c exhibit smectic mesophases within a broad temperature range. Unfortunately, the polymers show no remarkable increase of conductivity upon illumination.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 1047-1054 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The alkaline hydrolysis of some methyl methacrylate-ethyl acrylate copolymers in alkaline dimethyl sulfoxide leads to products containing carboxyl groups and having molecular weights which are significantly lower than those of the original copolymers. Size exclusion chromatographic (SEC) investigations provide detailed information on the degree of degradation and the influence of hydrolysis rate on degradation. Comparing the reactivities of structural units it is assumed that the degradation reaction occurs at the ethyl acrylate units.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 1085-1093 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A rhodium complex was anchored upon three types of phosphinated polystyrene which were crosslinked with divinylbenzene or ethylene dimethacrylate. Glass transitions were separately observed for the flexible polymer supports and their polymer-anchored rhodium complex catalysts using differential scanning calorimetry. Discontinuous activity drops in the Arrhenius plot for the ethylene hydrogenation reaction were observed for these flexibe polymer catalysts, while, for the rhodium complex anchored on a highly crosslinked rigid polymer, neither glass transition nor such a discontinuity in the catalytic activity could be detected. This reversible activity drop is discussed in terms of changes in the stability and the coordination state of the ethylene complex influenced by the micro-Brownian motion of the polymer network.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 1129-1136 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The flow properties of concentrated solutions of polyarylate from bisphenol A/50:50 isophthalic acid: terephthalic acid in m-cresol are studied. The results are discussed in terms of critical concentration Cc and critical molecular weight Mc for the onset of entanglements. Values of Cc = 8,2 wt.-% and Mc ≈ 3500 are obtained. The dependence of the Newtonian viscosities with temperature allows to obtain different energies of activation of flow for each polyarylate/m-cresol system, ranging from 9 to 13 kcal/mol (= 37,7 to 54,4 kJ/mol). The following free-volume-additivity equation is proposed to fit these data: \documentclass{article}\pagestyle{empty}\begin{document}$ E_{\rm a} = \frac{{V_{\rm p} \cdot \alpha _{\rm p} \cdot E_{{\rm ap}} + V_{\rm d} \cdot \alpha _{\rm d} \cdot E_{{\rm ad}} }}{{V_{\rm p} \cdot \alpha _{\rm p} + V_{\rm d} \cdot \alpha _{\rm d} }} $\end{document} where Ea, Eap, and Ead are the activation energies of the solution, the polymer and the solvent, respectively. Vp and Vd are the polymer volume fraction and the diluent volume fraction, respectively, and αp and αd represent the differences between the volume coefficients of expansion above and below the corresponding glass transition temperatures for the polymer and the solvent.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 2481-2488 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: 1,3-Butadiene was copolymerized with a mixture of divinylbenzene isomers containing ethyl-vinylbenzene isomers. The crosslinked copolymers were degraded in a cross metathesis reaction with (Z)-2-butene or (E)-3-hexene using the catalyst WCl6/Sn(CH3)4. The low-molecular-weight products were investigated by gas chromatography/mass spectrometry coupling. Products containing the crosslinks were found. Others were attributable to copolymer units resulting from butadiene and ethylvinylbenzene. Characteristic mass spectra of the products are discussed.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 2517-2522 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: New polysulfide polymers were prepared by a new process from vinyl monomers, elemental sulfur, and sodium metal in THF. The kinetic study of the reactions at -40°C has shown that the overall process can be described by the competition between a slow reaction (initiation of the monomer by the alkali metal) and a fast reaction (deactivation of the carbanion formed by elemental sulfur). These reactions lead to the establishment of a carbanion stationary state. From this data, the orders of magnitude of the apparent deactivation rates of the different carbanions were obtained: ca. 105 1·mol-1·s-1 for the styrene carbanion and 103-104 1·mol-1·s-1 for the butadiene carbanion.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 74
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 2553-2557 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Chloroprene rubber (CR) was allowed to react with 3-aminopropyltriethoxysilane (APS) and then cured by soaking in hot water. The moisture-cured rubber showed a network-chain density of 3,6·10-4 mol·cm-3 and a tensile strength at break of 10 MPa. The reaction of CR with APS was found to be a Menshutkin reaction. The activation energy and the frequency factor were 59 kJ·mol-1 and 4,3·104 l·mol-1·s-1, respectively.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 75
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Mechanism and kinetics of the reactions of N-(2,3-epoxypropyl)-N-methylaniline (1) with aniline or 4,4′-sulfonyldianiline (3) were investigated using high performance liquid chromatography and 13C FT NMR under different conditions (110-172°C). Comparison of 1 with its derivatives shows that the activity of the 2,3-epoxypropyl group in such epoxides depends on the structure and the substituents at the benzene ring; etherification may occur already before the secondary amine is consumed.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 76
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 1383-1389 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The formation of carboxylic acid groups (carboxyl + ester groups) was found in a threephase reaction of crosslinked poly(chloromethylstyrene) beads with an excess amount of sodium nitrite in immiscible solvents of benzene and water with tetrabutylammonium bromide as a phase transfer catalyst (PTC), and the dependence of carboxylic acid yield on the experimental conditions was studied. The product contains hydroxyl groups and ester bonds besides carboxyl groups. It was tentatively considered that the carboxyl groups are produced by direct oxidation of chloromethylstyrene groups by nitrous anions. Nitrous anions do not only act as a nucleophile but also as an oxidative reagent in this case.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 77
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 1641-1650 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The synthesis of monomeric and polymeric 5-methacryloylaminosalicylic acid derivatives is described. The interaction of these ligands with Fe(III), Ti (IV) and Ca(II) ions was investigated by photometric, conductometric and viscosimetric measurements.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 78
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 1683-1688 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The kinetics of hydroxymethylation of melamine (2,4,6-triamino-1,3,5-triazine) with formaldehyde to form N-(hydroxymethyl)melamine (2,4-diamino-6-hydroxymethylamino-1,3,5-triazine) was investigated in aqueous hydrogen phosphate/phosphate buffer solutions in the range of pH 10,51 to 12,20 at 20°C, determining unreacted melamine by means of HPLC. As a result, this reaction is subject to a general base catalysis, and the second order rate constant k is expressed by k = k′ + kA - [A-] + kp″[A-]2/[HA] (or kp‴ [A-][OH-]), where HA and A- denote acid and basic constituents of the buffer, and k′ is the rate constant in unbuffered media. This rate equation is compared with those reported previously.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 79
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 1501-1509 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dielectric relaxation properties of a combined main-chain/side-chain liquid-crystalline polymer were investigated. It was found that the rotation of the side chain about the main chain (δ-process) is not as strongly restricted as in side-chain liquid-crystalline polymers. This is attributed to the facts that the side chain is attached to the flexible spacer within the chain backbone and that the concentration of the side chains is comparatively small. Two low-temperature relaxation processes were observed to occur in the glassy smectic and the crystalline state. They are attributed to intramolecular motions with in the mesogenic groups.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 80
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 1597-1611 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The synthesis and characterization of liquid crystalline side chain polymers with mesogenic groups laterally attached to the polymer main chain are described. By variation of the terminal group, mesogenic moiety or spacer length, a change in the glass transition temperature, the nematic to isotropic transformation temperature and the stability of the nematic phase can be achieved. With increasing length of terminal groups, a distinct odd-even effect of the nematic to isotropic phase transformation temperature and also a strong decrease of the glass transition temperature is observed. Macroscopic homeotropic alignment can be achieved in an electric or magnetic field. Conoscopic investigations show optical biaxial behavior of the nematic phase. A chiral nematic copolymer is the first example of a thermotropic biaxial cholesteric phase.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 81
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Three active p-aminobenzenesulfonic acid derivatives, 1-(p-aminobenzenesulfonyl)imidazole (4a), 1-(p-aminobenzenesulfonyloxy)benzotriazole (4b), and 2-phenyl-4-(p-aminobenzenesulfonyl)-1,3,4-oxadiazoline-5-thione (4c) were synthesized by reacting p-isocyanatobenzenesulfonyl chloride (1) with stoichiometrical quantities of water in the presence of dibutyltin didodecanoate and subsequently with imidazole, 1-hydroxybenzotriazole and 2-phenyl-1,3,4-oxadiazoline-5-thione, respectively. The self-polycondensation of 4a-c, leading to poly(p-benzenesulfonamide) (7), was carried out in solution using polar aprotic solvents, N-methyl-2-pyrrolidone (NMP) and hexamethylphosphoric triamide (HMPA), and acidic media, dimethyl sulfoxide (DMSO) and m-cresol, with or without an appropriate acid catalyst or acid acceptor under mild conditions. Poly(p-benzenesulfonamide) having the highest reduced viscosity of 0,14 dl·-1 was obtained almost quantitatively from 4c by using m-cresol as a solvent without any acid catalyst and acid acceptor at 25°C. The polymers are soluble in polar aprotic solvents such as NMP, HMPA and DMSO and in aqueous sodium hydroxide. These poly(p-benzenesulfonamide)s are less thermally stable than completely aromatic polyamides, because the initial weight-loss started at 250-350°C. Aminolysis of three benzenesulfonic acid derivatives, 1-benzenesulfonylimidazole (5a), 1-benzenesulfonyloxybenzotriazole (5b), and 2-phenyl-4-benzenesulfonyl-1,3,4-oxadiazoline-5-thione (5c), with the same leaving groups was also carried out as a model reaction of self-polycondensation to determine the reaction conditions.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 82
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 2847-2856 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Optically active poly(styrene-co-methyl methacrylate) and poly(styrene-co-methacrylonitrile) were obtained by means of asymmetric copolymerization of 3,4-cyclohexylidene-D-mannitol-1,2; 5,6-bis{O-[(4-vinylphenyl)boronate]} (1) with methyl methacrylate and methacrylonitrile, respectively, removal of the D-mannitol template and splitting off boric acid from the resulting copolymers. By polymer analogous reactions, various functional groups were introduced to obtain optically active functional vinyl copolymers. The polymers were characterized by spectral and other analytical methods.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 83
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A series of rigid rod polyimides 1a-f derived from pyromellitic anhydride (PMDA) and 2,5-di-n-alkoxy-1,4-phenylenediamine containing flexible alkoxy side chains with 4 to 16 carbon atoms was prepared by solution polycondensation. As demonstrated by model experiments full conversion to the imide structure is achieved by reaction of PMDA with 2,5-dialkoxyphenylene diisocyanate, the latter compound being blocked by imidazole. The best solvent for the polycondensation, found in the course of the model reaction, is 1,3-dimethyl-2-oxo-perhydro-pyrimidine together with 4-dimethylaminopyridine as an accelerator. Wide-angle X-ray diffractograms showed that all polyimides under consideration here are highly crystalline at room temperature. The occurrence of a sharp reflection at the region of low angles together with its higher orders demonstrates the presence of a layered structure. The layer spacing was found to increase linearly with the length of the alkyl side chains. Polyimides bearing long side chains (n ≥ 10) exhibit two broad endotherms in the DSC analysis. As is revealed by wide-angle X-ray analysis the first transition is related to a disordering process of the side chains. The second transition leads to a layered high-temperature phase akin to the modification (B) found in a recent study of a similar rigid polyester bearing flexible side chains.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 84
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 2885-2893 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The flow of an electric current through an aqueous solution of acrylamide and NaNO3, using an activated iridium electrode as anode, induces the polymerization of the monomer in solution. The influence of the chemical and electrochemical variables on monomer conversion was studied. The experimental results point to the production of initiating radicals by charge transfer between the electrolyte and the electrode, followed by desorption of these radicals from the electrode into the solution. The electrode process is a mixed process in which all the species present take part. Electrode activation depolarizes the NO-3 discharge and increases the polymerization rate.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 85
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 2921-2934 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The thermodynamical properties of poly(dimethylsiloxane) (PDMS) were studied in the theta-solvent styrene. Moderately diluted and semidiluted solutions of three PDMS samples with weight-average molecular weights M̄w = 23 500, 160 000, and 860 000 were investigated by means of light scattering near the theta-temperature. The dependency of the interaction parameter X on temperature and concentration was established for the three samples. The study of the third virial coefficient A3 showed that A3 is independent of molecular weight and temperature as predicted by theory. However, the experimental value of A3/(A22M) was higher than expected. The critical properties, i.e., critical point and spinodal, were considered.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 86
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 2951-2961 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Phenethyl 2-(methoxycarbonylmethyl)acrylate (methyl penethyl itaconate) (1) was prepared and its polymerization with dimethyl 2,2′-azoisobutyrate (2) was investigated kinetically in benzene. The polymerization rate (Rp) was found to be expressed by Rp = k·[2]0,5·[1]1,8 (at 50°C). Further, a higher dependence of Rp (2nd order) on the concentration of 1 was observed at 61°C. The overall activation energy of the polymerization was calculated to be a low value of 50,3 kJ/mol. The initiator efficiency (f) of 2 was determined to be 0,48 to 0,22 at 50°Cand 0,50 to 0,28 at 61°C. f decreases with increasing monomer concentration due to the high viscosity of 1. The poly(1) radical is stable enough to be observable by ESR at high temperatures (50-60°C). Rate constants of propagation (kp) and termination (kt) were estimated using the poly(1) radical concentration determined by ESR. kp [6,0 to 121/(mol·s) at 50°Cand 7,1 to 15 1/(mol·s) at 61°C] shows a trend to increase with the concentration of 1. On the other hand, kt [2,9·104 to 17·1041/(mol·s) at 50°Cand 6,9·104 to 45·1041/(mol. s) at 61°C] decreases with increasing MPI concentration. This behavior is responsible for the high order with respect to monomer concentration. Copolymerization of 1 (M1) with styrene (M2) at 50°Cgave the following results: r1 = 0,36, r2 = 0,40, Q1 = 0,82 and e1 = + 0,59. Using the above results, the rate constants of the cross-propagations were estimated to be k12 = 22 1/(mol·s) and k21 = 308 1/(mol·s) at 50°C.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 87
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 2983-2993 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polymers with pendent p-dialkylaminobenzylideneracetophenone (PABA) groups were prepared by copolymerization of 4-(4-dimethylaminobenzylidenemethylcarbonyl)phenyl methacrylate (1) with alkyl methacrylates and by the substitution reaction of poly(chloromethylstyrene-co-methyl methacrylate) with sodium 4-(4-dimethylaminobenzylidenemethylcarbonyl)phenolate (3). The polymers having PABA groups become insoluble upon photodimerization of PABA. Furthermore, the photosensitivity of the polymers increases considerably when mixed with vinyl monomers and diphenyliodonium hexafluorophosphate (DPI) during irradiation. The photocrosslinking may involve graft polymerization initiated by PABA which sensitizes the decomposition of DPI to form radicals. Introduction of unsaturated groups like maleate or crotonyl groups into the PABA polymer depresses the shrinkage of the photocured polymer film when the polymer was mixed with DPI. Sensitivity characteristics of PABA polymers toward Ar laser emitting 488 nm light are mentioned.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 88
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The inhibition constants (KI) of aliphatic and aromatic amide derivatives of phenylalanine and proline for GS1 and GS2 of the enzyme system gramicidin S synthetase were determined. These compounds act as competitive inhibitors. Some of these compounds (spacer/ligand compounds) were reacted with epoxy-activated Sekpharose 6B or with crosslinked poly(vinyl alcohol). The resulting - for GS1 or GS2 more or less specific - adsorption materials, were used for the purification of these multi-enzyme systems.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 89
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 2231-2239 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The morphology and the texture of thin films of ethylene/propylene copolymers with crystallizable polypropylene blocks was investigated by optical and electron microscopy as a function of both molecular composition and crystallization conditions. The thermal and melting behaviour was also studied. It was found that variables such as the observed melting point as well as the enthalpy and the entropy of fusion are composition dependent. Contrary, the equilibrium melting temperature seems to be invariant with composition in agreement with the block type of the investigated copolymers.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 90
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: 1-Vinyl-4,5,6,7-tetrahydroindole in the presence of Brønsted acids (HCl, H2SO4, HOAc) and Lewis acids (BF3 · OEt2, FeCl3, TiCl3, SnCl4, SiCl4, Et3SiCl, Me2, PhMeSiCl2) undergoes an alternative oligomerization involving both the double bond and the α-position of the pyrrole ring to form the dimer 1-vinyl-2-[1-(4,5,6,7-tetrahydro-1-indolyl)ethyl]-4,5,6,7-tetrahydroindole in a yield up to 68% and oligomers of the same backbone, soluble (major product) and insoluble (minor product) in hot hexane, the latter being enriched by oxidized and hydrolyzed tetrahydroindole units. The molecular weights of the former oligomers were assessed from 1H NMR spectra to range from 1000 to 2000.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 91
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Protected nucleic acid components were coupled to eight differently functionalized bead copolymers, prepared from methyl acrylate and 1,4-bis(vinyloxy)butane, via amid-, urea-, phosphotriester- or carboxylic acid ester linkages. The immobilization was performed by methods used in nucleic acid chemistry. The obtained gels carry 1 to 300 μmol per gram of nucleoside or nucleotide derivatives. The yield of derivatization was found to be first of all determined by steric effects of the gel matrix, the size of the nucleic acid component and the route of synthesis selected. Anchor groups, arranged via long spacers, were not effective for the immobilization of nucleic acid components. A “carboxylate-gel” which can immobilize 300 μmol per gram of a nucleoside derivative may serve as support in the solid phase synthesis of oligonucleotides in large scale.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 92
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 2293-2300 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Poly(N-tert-butyliminoethylene) was quaternized with several agents. Only the very reactive methyl trifluoromethanesulfonate allowed to attain relatively high quaternization degrees after short reaction times. The maximum degree of quaternization was 0,44. This was attributed to the complete lack of reactivity of amino functions which have a quaternized neighbour. By means of 1H NMR spectroscopy it was possible to measure the fractions of the different triads and . Analysis, by means of Monte Carlo calculations, of the relative amount of these triads as a function of the degree of quaternization lead to the conclusion that the reactivity of the first, second and third nitrogen next to an ammonium function is 0,0,20 and 0,57, respectively, the reactivity of a nitrogen in an ammonium-free chain being 1. This shows that the electrostatic deactivation exerts its action to at least nine atoms away from the charged atom. The quaternized polymer is unstable even at room temperature. After a few days the formation of isobutene is observed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 93
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 2353-2370 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A theory was developed for predicting the self-diffusion coefficients Dp of macromolecules and of oligomers in solution and in the melt. For moderate-concentration ranges account was taken of decreasing intramolecular hydrodynamic interaction with increasing concentration. In the high-concentration range the scaling theory was used. The dependence of Dp on concentration, molecular weight, and quality of the solvent was described by a common relationship as a function of √c[η] with mass concentration c and intrinsic viscosity [η]. If the dependence is considered in the form Dp ∝ cβ, then the value of the exponent β varies between 0 and 2. If the dependence of the local viscosity is taken into account, then β is greater than 2. An analysis of the relationships of Dp for oligomers and polymers in melts was also conducted. The theoretical results obtained describe quantitatively the available experimental data. These results were used for the interpretation of the decreasing decay rate of macroradicals with increasing conversion (gel effect).
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 94
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 119-133 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: New trans- and cis-polydecaorganocyclohexasiloxanes of intermediate tacticity between transtactic and cistactic and atactic were prepared by heterofunctional polycondensation of the trans- and cis-isomers of 2,8-dichlorodecaorganocyclohexasiloxanes with the corresponding dihydroxydecaorganocyclohexasiloxanes. Composition and molecular structure of polymers obtained were determined by means of elemental analysis, IR and 29Si NMR spectroscopy, intrinsic viscosity, and molecular weight analysis. Using DSC, X-ray and optical analysis the influence of chain tacticity on the formation of a mesophase and on the crystalline state was determined. All the polymers studied exhibit a mesophase state the temperature interval of which is dependent on chain tacticity.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 95
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polymerizable N2-(4-chloro-2-methylphenyl)-N1-methylformamidine derivatives of (N-demethyl-chlordimeform) (2) were prepared, bearing either 4-vinylbenzyloxy- or 2-methacryloyloxyethoxycarbamoyl groups (5 and 7), and in addition, a triazatriphosphorine derivartive of 2 (8). The carbamoyl groups and the P-N linkages in the monomers, respectively, were specifically designed to release the insecticide 2 under the particular microenvironmental conditions on cotton leaves by hydrolytic cleaveage, triggered by the pH 8-10 of the leaf surface. Biossaying experiments using larvae of the Egyptian Cotton Leafworm (Spodoptera littoralis) on cotton plants confirmed methacrylate 7 as the only compound with sufficient bioactivity. Corresponding homo- and copolymers of 7, containing covalently bound pendent moieties of 2, showed advantageous physiochemical properties with regard to improved efficiency and reduced environmental and handling risks in conventional foliar applications. The biological data suggest that the release rates of the active agent from the polymers vary significantly, depending on the hydrophilicity of the comonomers and the type of formulation used.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 96
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 333-339 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A mathematical procedure is developed to deal with the kinetics of ionic polymerization with impurity transfer and instantaneous initiation. Besides the technique of variable transformation, the integration of an implicit function is applied. The expressions of the molecular size distribution function and other molecular parameters are derived regorously, and several examples for numerical computations are given.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 97
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 1195-1204 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A method of obtaining good quality ultrathin sections from nylon 6 bulk samples has been developed by using a special embedding technique and cryo-ultramicrotomy. The morphologies of nylon 6 processed by compression and injection molding and of reaction injection molded nylon 6 were studied in ultrathin sections of bulk samples by means of transmission electron microscopy. It was established that the spherulites of nylon 6 in bulk are built up from long flat ribbonlike lamellae. The thickness of the lamellae is in the range 50-60 Å. The width varies from 150 to 600 Å and depends on the type of nylon 6 and the method of processing. The length of the lamellae is relatively large approaching spherulite radii, extending often from the point of their origin up to the spherulite borders. Three or four neighboring lamellae within spherulites usually show similar orientation of their flat faces and form domains which can easily be mistaken for fibrils in light microscopy or low resolution electron microscopy.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 98
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 1273-1279 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Functional polypropylenes having vinyl, phenyl or hydroxyl groups at the chain end were prepared by adding common monomers as butadiene, styrene and 1,2-epoxypropane, respectively, at -78°C during the living coordination polymerization of propene with a soluble V(acac)3/Al(C2H5)2Cl catalyst. In addition, polypropylene with hydroxyl functions was prepared by an alternative method based on the hydrogenation of a polypropylene containing aldehyde functions with LiAlH4. These new types of terminally functionalized polypropylenes were well-characterized by 1H NMR analysis.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 99
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The relative affinity of various mono and difunctional sulfoxides for lithium picrate in toluene was investigated by a competition method utilizing immobilized linear polyethers (glymes). In general, the difunctional sulfoxides were found to bind more strongly than the monofunctional sulfoxides. However, difunctional ligands which would result in eight-membered ring chelated structures bound lithium ion more strongly than those which would result in six-membered ring chelated structures.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 100
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 188 (1987), S. 1651-1658 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The propagation reaction of 4′-methylenespiro[2-benzofuran-2,2′-(1,3-dioxolane)] (2), initiated by a free radical initiator, was studied by analysis of the polymer structure and by kinetic investigation. The results indicate that the polymer has the structure of poly [methylene-spiro[2-benzofuran-2,2′-(1,3-dioxolane)]-4′-ylidene-co-(2-oxotrimethylene)] (10). A reasonable propagation mechanism is proposed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...