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  • 1
    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: Beginning with the current theories concerning the solid state structure of bisphenol-A-polycarbonate, the effect of chemical substitution of the bisphenol upon the thermal, mechanical, and dynamic mechanical properties will be discussed in detail. The observed mechanical properties of the various polycarbonates is considerably influenced by their chemical structure. Among all of the polycarbonates, bisphenol-A-polycarbonate is unique, particularly with respect to its low temperature properties. The ductile-to-brittle transition as a function of temperature correlates to the high temperature region of Gamma relaxation (G′′). Any theoretical approach to completely characterize and describe the experimentally observed phenomena must take into consideration as a fundamental parameter the conformational flexibility of the polycarbonate chain.
    Notes: Ausgehend von den bisher erarbeiteten Vorstellungen über die Festkörperstruktur des Bisphenol-A-Polycarbonats wird die Auswirkung einer chemischen Substitution des Bisphenols auf die thermischen, mechanischen und mechanisch-dynamischen Eigenschaften diskutiert. Innerhalb der Substanzklasse der Polycarbonate zeigt sich dabei hinsichtlich der beobachteten mechanischen Phänomene ein erheblicher Einfluß der chemischen Struktur. Vor allen Polycarbonaten ist das Bisphenol-A-Polycarbonat besonders hinsichtlich seiner Tieftemperatur-Eigenschaften ausgezeichnet. Der Spröd/Zäh-Übergang als Funktion der Temperatur korreliert mit der Hochtemperaturflanke des mechanischen Nebenrelaxationsgebietes. Eine die experimentell beobachteten Phänomene vollständig charakterisierende Theorie muß als wesentlichen Parameter die konformative Beweglichkeit der Polycarbonat-Ketten berücksichtigen.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 30 (1990), S. 1133-1139 
    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: Birefringence is an important substrate property for optical data storage media. The basic definitions of birefringence and its relation to the chemical nature of polycarbonate are outlined. The polarizability of the monomer unit, expressed in the rheo-optical constant and the degree of remaining polymer chain orientation, determines the level of birefringence in polycarbonate disk substrates. Based on this theory, the theory of blending materials with positive and negative rheo-optical constants Is developed, and the current work with polycarbonate/polystyrene blends is reviewed. The biggest disadvantage of the reviewed system Js that only binary systems with low LCST (lower critical solution temperature) (〈240°C) can be formulated. Finally, we report on successful development work of a single-phase blend of a modified polycarbonate with a special styrene-acrylonitrile copolymer. The experimental results are compared with the theoretical expectations, and the implications on the injection molding of disk substrates are discussed.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 162 (1988), S. 87-107 
    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 continuous growth of polycarbonate and the increasing variety of applications make it necessary to improve the basic physical understanding and to transfer the main physical ideas also into the more commercial fields. The present paper tries to give an overview about the most important physical aspects which are the basis for nearly all of the technological properties. The following items are discussed: deformation mechanisms, dynamic mechanical relaxation, stress strain behaviour, ductile/brittle transition, influence of sample thickness, physical aging, orientation behaviour, environmental stress cracking. A qualitative model for the solid state structure is discussed.
    Notes: Die sich ausweitenden Einsatzbereiche des PolycarbonatsPolycarbonat auf Basis von Bisphenol A (im Text als BPA-PC oder einfach als PC bezeichnet). (PC) machen es notwendig, das Verständnis für die physikalischen Grundlagen auch in die mehr anwendungsorientierten Bereiche hineinzutragen. Der vorliegende Artikel macht den Versuch, die wichtigsten polymerphysikalischen Aspekte, auf denen eine Vielzahl von technologischen Eigenschaften beruht, in Form einer Übersicht darzustellen. Behandelt werden: Deformationsmechanismen, dynamisch-mechanisches Relaxationsverhalten, Spannungs-Dehnungsverhalten, Zäh/Spröd-Übergang, Einfluß der Probendicke, physikalische Alterung, Orientierungsverhalten, Spannungsrißbildung in Medien.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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