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  • 1
    Electronic Resource
    Electronic Resource
    Untersuchungen zur Plasmaätzung von Polymeren. Teil I: Strukturänderungen von Polymeren nach Plasmaätzung (1979)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 30 (1979), S. 470-477 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: In the plasma of electrical discharges polymer samples are subjected to oxidation causing reactive sites or to degradation. Further, a significant volume (depth) effect in a 5 to 10 μm surface layer was observed which was caused by plasma UV radiation. These photolytical effects result in changes of the polymer structure, as crosslinking, change of crystallinity, radical formation etc. Therefore, the etching patterns reflect the features of secondary structures formed by these processes.
    Notes: Polymere werden im Plasma einer elektrischen Entladung an der Oberfläche funktionalisiert (oxydiert) bzw. abgebaut. Daneben wurde jeweils ein signifikanter, auf eine 5 bis 10 μm starke Schicht an der Oberfläche beschränkter Volumeneffekt („Tiefeneffekt“) beobachtet, der durch die Plasma-UV-Strahlung verursacht wird. Diese photolytischen Erscheinungen führen zu Änderungen im Polymergefüge wie Vernetzung, Veränderung der Kristallinität, Radikalbildung usw. Abbildungen von Polymerätzstrukturen spiegeln deshalb in gewissem Umfang die solchermaßen veränderte Sekundärstruktur wider.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1979.010300802
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  • 2
    Electronic Resource
    Electronic Resource
    Reaktionen polyfunktioneller Cyansäureester mit polyfunktionellen Glycidethern. 2. ReaktionsmodellTeil 1: siehe [1] (1989)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 40 (1989), S. 397-401 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: A model of the reaction between glycidylethers and aromatic cyanates is established. It was found that the trimerization of cyanates, the insertion of glycidylethers, the isomerisation of alkylcyanurates, the oxazolidinone build up, the abstraction of the phenols, and the phenol/glycidylether-addition are the main reactions.
    Notes: Ein Reaktionsmodell der Umsetzung von Glycidethern mit aromatischen Cyansäureestern wird begründet. Als Hauptreaktionen wurden die Trimerisierung der Cyansäureester, die Einschubreaktion der Glycidether in die Cyanuratstruktur, die Isomerisierung der Alkylcyanurate, die Oxazolidinonbildung, die Phenolabspaltung und die Phenol/Glycidether-Addition gefunden.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1989.010400608
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  • 3
    Electronic Resource
    Electronic Resource
    Kinetics and modelling of thermal polycyclotrimerization of aromatic dicyanates (1986)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 37 (1986), S. 715-719 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Kinetik der thermischen Polycyclotrimerisierung von 2,2-Bis(4-cyanatophenyl)propan wurde mit Hilfe von DSC und IR-Spektroskopie untersucht. Der autokatalytische Charakter der Reaktion wurde durch Modellierung der Umsatz-Zeit-Kurven bei Zusatz difinierter Mengen der nachgewiesenen Zwischenprodukte aufgeklärt. Weiterhin wurden quantitative Beziehungen zwischen Reinheitsgrad des Dicyanats, Geschwindigkeit der Bruttoreaktion, Lage des DSC-Maximums und B-Zeit gefunden.
    Notes: The kinetics of polycyclotrimerization of 2,2-bis(4-cyanatophenyl)propane was analyzed by differential scanning calorimetry and IR spectroscopy. The autocatalytic character of the reaction was elucidated by modelling the conversion-time curves of systems with definite admixtures of the found intermediate products. Furthermore, quantitative relations between the purity of the dicyanate, the rate of the brutto reaction, the temperature of the DSC maximum, and the B-time of the resin were found.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1986.010371112
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  • 4
    Electronic Resource
    Electronic Resource
    A new approach of characterizing the hydrolytic degradation of poly(ethylene terephthalate) by MALDI-MS (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 2183-2192 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The hydrolytic degradation of technical poly(ethylene terephthalate) (PET) was investigated by means of different methods such as size-exclusion chromatography (SEC), viscometry, light-scattering, thin-layer chromatography, end-group titration, and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The long-term degradation was simulated by exposing PET filament yarns to aqueous neutral conditions at 90°C for up to 18 weeks. By means of MALDI-MS and thin-layer chromatography, the formation of different oligomers was obtained during polymer degradation. As expected, an ester scission process was found generating acid terminated oligomers (H-[GT]m-OH) and T-[GT]m-OH and ethylene glycol terminated oligomers (H-[GT]m-G), where G is an ethylene glycol unit and T is a terephthalic acid unit. Additionally, the scission of the ester bonds during the chemical treatment led to a strong decrease in the number of cyclic oligomers ([GT]m). The occurrence of di-acid terminated species demonstrated a high degree of degradation. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2183-2192, 1997
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Analytik von Prepolymeren und Polymeren aromatischer Cyansäureester. 1. IR-Spektroskopie (1986)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 37 (1986), S. 218-220 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: It is shown that the CN stretching band in the region 2200 to 2300 cm-1 is suitable for fast and reliable evaluation of the OCN-conversion in soluble and gelled trimerisates of aromatic cyanic acid esters. As an internal standard the aromatic CH-stretch band is used.
    Notes: Es wird gezeigt, daß die charakteristische CN-Valenzschwingungsbande im Bereich von 2200 bis 2300 cm-1 zur schnellen und sicheren Bestimmung des OCN-Umsatzes in löslichen und gelierten Trimerisierungsprodukten aromatischer Cyansäureester geeignet ist. Als innerer Standard findet dabei die aromatische CH-Valenzschwingungsbande Verwendung.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1986.010370408
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  • 6
    Electronic Resource
    Electronic Resource
    Die katalysierte Umsetzung substituierter Harnstoffe mit Isocyanaten zu Biureten (1981)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 32 (1981), S. 27-30 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: A model system consisting of isocyanate and substituted urea is chosen to demonstrate the ability of ethyl- and butyltintrichloride as well as bis(tributyl-tin) oxide to accelerate biurete formation. These reactions are quantified by means of second order rate constants. The activation energy is determined for the reaction in the presence of butyl-tin-trichloride.
    Notes: An einem Modellsystem Isocyanat/substituierter Harnstoff wird gezeigt, daß Ethyl- und Butylzinntrichlorid sowie Bis(tributylzinn)oxid die Biuretbildung beschleunigen können. Die Reaktionen werden mit Geschwindigkeitskonstanten zweiter Ordnung quantifiziert, und für die Umsetzung in Gegenwart von Butylzinntrichlorid wird die Aktivierungsenergie bestimmt.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1981.010320107
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