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  • Polymer and Materials Science  (6)
  • Wiley-Blackwell  (6)
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  • Wiley-Blackwell  (6)
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  • 1
    Electronic Resource
    Electronic Resource
    Zur kinetik der anionischen polymerisation von methyl-methyacrylat in tetrahydrofuran bei -75°C (1973)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 172 (1973), S. 137-149 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The anionic polymerization of methylmethacrylate (MMA) in tetrahydrofuran (THF) at -75°C with cumylcesium or α-methylstyrylcesium as initiators proceeds without any detectable side reactions and in analogy to the anionic polymerization of nonpolar monomers in polar solvents. The argument for this statement mainly is the narrow molecular weight distribution of the poly(methyl methacrylates) which were obtained under these conditions.At -75°C the rate constants of the monomer addition for the ionpair are kw(±) = 80 dm3 mol-1 s-1 and for the free anion kw(-) ≍ 6 · 104 dm3 mol-1 s-1, resp. Conductivity measurements reveal that the dissociation constant of polymethylmethacrylcesium at this temperature is approximately 10-9 mol dm-3.
    Notes: Die anionische Polymerisation von Methylmethacrylat (MMA) in Tetrahydrofuran (THF) verläuft bei -75°C mit Cumylcäsium bzw. oligomerem α-Methylstyrylcäsium als Initiatoren ohne erkennbare Nebenreaktionen analog der anionischen Polymerisation von unpolaren Monomeren in ätherischen Lösungsmitteln. Als Beweis wird hauptsächlich die enge Molekulargewichtsverteilung der unter diesen Bedingungen hergestellten Polymethylmethacrylate angeführt.Bei -75°C betragen die Geschwindigkeitskonstanten für die Monomeranlagerung an das Ionenpaar kw(±) = 80 dm3 mol-1 s-1 und an das freie Anion etwa kw(-) ≍ 6 · 104 dm3 mol-1 s-1. Leitfähigkeitsmessungen ergeben, daß die Dissoziationskonstante des Polymethylmethacrylcäsiums bei dieser Temperatur bei 10-9 mol dm-3 liegt.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1973.021720113
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  • 2
    Electronic Resource
    Electronic Resource
    Estimation of the rate constant of termination by the monomer in the anionic polymerization of methyl methacrylate (1974)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 175 (1974), S. 497-505 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Unter der Voraussetzung, daß der Abbruch bei der anionischen Polymerisation von Methylmethacrylat in Tetrahydrofuran mit Cumylcäsium als Initiator ausschließlich durch das Monomere verursacht wird, wird die Abbruchsgeschwindigkeitskonstante kt± für die Ionenpaare des Polymethylmethacrylcäsiums aus der Molekulargewichtsverteilung von Polymeren, die bei verschiedenen Temperaturen unter sonst gleichen Bedingungen hergestellt wurden, abgeschätzt. Die Abbruchreaktion hat eine Aktivierungsenergie von etwa 11 kcal/mol (46 kJ/mol). - Die relativ große Breite der Verteilung der nicht desaktivierten Ketten („interne Uneinheitlichkeit“) zeigt deutlich die Existenz von verschieden reaktiven Ionenpaararten.
    Notes: Based on the assumption that the termination reaction in the anionic polymerization of methyl methacrylate in THF with cumyl cesium as initiator is exclusively caused by the monomer, the termination rate constant kt(±) for the ion-pairs of polymethylmethacrylcesium is estimated by analyzing the molecular weight distribution (MWD) of polymer samples prepared at different temperatures under otherwise identical reaction conditions. The activation energy of the termination reaction of the ion-pairs is found to be about 11 kcal/mol (46 kJ/mol). - The relatively broad MWD of the non-deactivated chains (the so called internal nonuniformity) reveals the existence of ion-pairs with different reactivity.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1974.021750213
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  • 3
    Electronic Resource
    Electronic Resource
    An automatically controlled reaction vessel suitable for the kinetic investigation of polymerization processes with half life periods of 2 seconds and greater (1978)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 179 (1978), S. 2211-2219 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A reaction vessel automatically controlled by magnetic valves is described which allows kinetic measurements of reactions with half lives t1/2≥2s by gravimetric determination of the conversion. Thus, it covers the gap between the flow tube and the conventional reaction vessel.The influence of mixing time and filling time on the molecular weight distribution of an anionically prepared polymer is discussed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1978.021790910
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  • 4
    Electronic Resource
    Electronic Resource
    Utilization of aerosolspectroscopy for determination of the particle size distribution of aqueous dispersions in the submicroscopic rangeDedicated to Prof. Dr. R. Sammet on the occasion of his 60th birthday (1980)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 85 (1980), S. 181-195 
    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: Ein kürzlich entwickeltes Aerosolspektrometer bietet eine neue Methode, um die Partikelgröße wäßriger Dispersionen im submikroskopischen Bereich zu bestimmen. Diese Technik verbindet einfaches Präparieren der Probe und schnelles Messen mit ausge zeichneter Auflösung. Die Brauchbarkeit der Methode wird an einigen typischen Beispielen demonstriert.
    Notes: A recently developed aerosolspectrometer offers a new method for particle size analysis of aqueous dispersions in the submicroscopic range. This technique combines simple sample preparation and quick measurement with excellent resolution. The usefulness of the method is demonstrated by some typical examples.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1980.050850113
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  • 5
    Electronic Resource
    Electronic Resource
    Über den einfluß der monomerkonzentration auf die geschwindigkeitskonstante kw(±) der monomeraddition an das ionenpaar eines „lebenden“ polymerenHerrn Prof. Dr. F. PATAT zum 60. Geburstag gewidmet (1966)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 96 (1966), S. 283-289 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The rate constant kw(±) for the addition of monomer to the ion pair of a „living“ polymer was measured by workers in Mainz and in Syracuse. Their results lack agreement. It was assumed that this disparity is caused by the different monomer concentrations used which differed by some orders of magnitude. In this work we assume a faster polymerizing complex between the ion pair and the monomer. The corresponding kinetical scheme is evoluated.
    Notes: Für den Zahlenwert der Geschwindigkeit skonstante kw(±) fanden die Arbeitsgruppen in Mainz und Syracuse voneinander abweichende Werte. Es wurde angenommen, daß die Ursache dieser Diskrepanz die um Größenordnungen verschiedenen Konzentrationsbereiche sind, in denen die Messungen ausgeführt wurden. Nachfolgend wird ein Reaktionsschema vorgeschlagen und kinetisch durchgerechnet, welches eine schneller polymerisierende Komplexverbindung zwischen dem Ionenpaar und dem Monomeren voraussetzt.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1966.020960123
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  • 6
    Electronic Resource
    Electronic Resource
    Rate constants for ion-pair dissociation and association in the anionic two-state polymerization of styrene in THF (1965)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Letters 3 (1965), S. 985-991 
    Details
    ISSN: 0449-2986
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1965.110031203
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