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  • Polymer and Materials Science  (3)
  • Inorganic Chemistry
  • 1980-1984  (3)
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Keywords
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  • 1
    Electronic Resource
    Electronic Resource
    Mikrophasen und LC-strukturen von aliphatischen blockcopolyethern in gegenwart von wasserVortrag anläßlich der Tagung der Fachgruppe “Makromolekulare Chemie” der Gesellschaft Deutscher Chemiker über “Polymere und Wasser” am 2. und 3. April 1984 in Bad Nauheim (1984)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 123 (1984), S. 189-216 
    Details
    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: Blockcopolyethers of ethylene oxide (EO) and propylene oxide (PO) are molecular homogeneous in the dry state. When water is added most of it is physically bonded to the EO blocks. This leads to a considerable increase of the viscosity. At higher water concentrations the system forms a thermoreversible gel. It could be demonstrated by quantitative Small Angle X-Ray Scattering that a progressive microphase separation takes place. In this process a stochimoetric 1 : 1-complex of ethylene oxide and water plays an important role. The gelation ist correlated with the appearance of a lamellar order, i.e. an amphiphilic liquid crystalline phase. This long range supermolecular structure has to be regarded as the reason for the elastic behavior of the systems at high water concentrations.
    Notes: Blockcopolyether aus Ethylenoxid (EO) und Propylenoxid (PO) bilden im wasserfreien Zustand einphasige Systeme. In Gegenwart von Wasser findet eine weitgehend selektive Solvatisierung der EO-Blöcke statt. Diese führt zu einem starken Viskositätsanstieg und bei höheren Wassergehalten zur Bildung eines thermoreversiblen Gels. Durch quantitative Röntgenkleinwinkelmessungen konnte gezeigt werden, daß sich mit steigendem Wassergehalt in zunehmendem Maße eine Mikrophasenbildung vollzieht, wobei dem 1 : 1-Komplex aus Ethylen-oxid und Wasser eine besondere Bedeutung zukommt. Die Gelbildung ist verknüpft mit dem Auftreten einer lamellaren Struktur, die eine amphiphile LC-Phase darstellt. Diese weitreichende übermolekulare Ordnungsstruktur ist als Ursache für die elastischen Eigen-schaften solcher Systeme anzusehen.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1984.051230108
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  • 2
    Electronic Resource
    Electronic Resource
    On the structure of polyurethane hard segments based on MDI and butanediol-1,4: X-ray diffraction analysis of oriented elastomers and of single crystals of a model compoundDedicated to Professor Herbert Grunewald on the occasion of his 60th birthday. (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 22 (1984), S. 163-173 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Single-crystal x-ray diffraction analysis is performed on a model compound (bisurethane of diphenylmethane-4-monoisocyanate and butanediol-1,4) for the thermoplastic polyurethane (TPU) hard segment formed from diphenylmethane-4,4′-diisocyanate and butanediol-1,4. The resulting structure is compared to structure models of corresponding TPU hard segments, especially to the structure proposed by Blackwell and Ross. Our results confirm this structure model showing a planar zigzag of the (CH2)4 group and planar hydrogen bonding between the urethane groups of adjacent molecules. X-ray diffraction analyses of polymeric TPU hard segments and of TPU elastomers with noncrystallizing soft segments lead to a revision of the dimensions of the proposed lattice cell, resulting in a more plausible value of 1.3226g/cm3 for the crystal density.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.180220202
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  • 3
    Electronic Resource
    Electronic Resource
    Elektronenbeugungsuntersuchungen an Polyethylenschichten auf Quarz (1982)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 33 (1982), S. 408-412 
    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: HD-PE layers formed on quartz monocrystal surfaces from dilute solutions were investigated by electron diffraction to test the influence of the substrate on the polymer structure. The PE chains proved to be arranged parallel to the quartz surface and epitaxial intergrowth is possible. Both orthorhombic and monoclinic modifications of PE were observed. Epitaxy relations are derived and discussed, and the influence of annealing on the layer structure was investigated.
    Notes: Aus verdünnten Lösungen auf Quarzeinkristallen abgeschiedene Filme von HD-PE wurden mit Hilfe der Elektronenbeugung untersucht, um zu überprüfen, welchen Einfluß die Unterlage auf die Polymerstruktur besitzt. Es wurde festgestellt, daß sich die Polymerketten parallel zur Quarzoberfläche ausrichten und epitaktische Verwachsungen auftreten können, wobei neben der orthorhombischen auch die monokline Modifikation in Erscheinung trat. Epitaxiebeziehungen werden abgeleitet und strukturell diskutiert. Außerdem wird der Einfluß einer Temperbehandlung auf die Schichtstruktur untersucht.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1982.010330702
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