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  • 1
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 3 (1960), S. 20-25 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: The polymerization of propylene with AlEt3—TiCl4 catalyst was studied in detail. The molecular weight of polymers decreases with the temperature in the range 2-40°C., and increases proportionally to the pressure, but it does not depend on the AlEt3/TiCl4 ratio. The rate is proportional to the amount of catalyst as well as to the propylene pressure. The optimum mole ratio of AlEt3 to TiCl4 is 4. In regard to the temperature, the rate is maximum at 40°C. The apparent activation energy is about 5.7 kcal./mole for the range 2-40°C. The activity of the catalyst decreases with the length of time it is kept at 40-60°C. after its formation, but at 30°C. the activity is retained almost completely for 4 hr. The polymerization rate is observed to decrease as the reaction proceeds, even at constant pressure. It is unreasonable to attribute this fact solely to the deactivation of catalyst observed at above 40°C., because such a decrease in rate occurs even at 30°C.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 55 (1961), S. 285-296 
    ISSN: 0022-3832
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The polymerization of ethylene initiated by di-tert-butyl peroxide is studied in batch system under pressures ranging from 300 to 1700 kg./cm.2, and at temperatures of 110 to 170°C., using reaction mediums of water, ethyl alcohol, and their mixture. An experimental rate equation in water is: \documentclass{article}\pagestyle{empty}\begin{document}$ R = 4.2 \times 10^{17} {\rm exp}\left\{ {{{ - 42,100} \mathord{\left/ {\vphantom {{ - 42,100} {RT}}} \right. \kern-\nulldelimiterspace} {RT}}} \right\}{\rm [}I_0 ]{\rm exp}\left\{ { - k_d t} \right\}P^{1.9} , $\end{document} The rate is proportional to the concentration of radical produced by the first-order decomposition of initiator. A reaction scheme is proposed from which this rate equation can be derived. According to this scheme, the deactivation of radical is kinetically of the first order with respect to the radical concentration. Several relations between the reaction conditions and properties of polyethylene produced are also described.
    Zusätzliches Material: 14 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 55 (1961), S. 321-334 
    ISSN: 0022-3832
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: This study of Al-TiCl4 catalysts for olefin polymerization continues work reported in preceding papers but with the use of aluminum wire under constant pressures. The use of aluminum having a very small surface area was convenient for the kinetic study of the reaction mechanism. The reaction time is divided into four periods. The first and second are connected with active-center formation and are considered to be a kind of induction period. The third is a stationary period in which the rate is proportional to the square of pressure and the activation energy is ca. 16 kcal./mole. In the fourth period the rate is proportional to pressure and decreases gradually owing to a rate-controlling diffusion step through the polymer layer produced. A kinetic consideration is proposed and a reaction scheme formulated for initiation, propagation, transfer, and termination. An ethylene-propylene copolymerization study was also carried out, and lead to the supposition of a cationic mechanism in respect to the present type of polymerization.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 78 (1964), S. 216-223 
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Die Elementarreaktionen der strahlungsinduzierten Polymerisation von 3,3-Bischlormethyloxetan in festem Zustand wurden mit Hilfe von Massenspektrometrie und Gasphasenchromatographie untersucht. Gasförmige und andere Nebenprodukte bei der Polymerisation wurden gemessen. Die bei γ-Bestrahlung entwickelten Gase waren H2, CO und CO2. Es wird angenommen, daß der G-Wert der aktiven Polymerisationszentren wesentlich tiefer liegt als der anderer Elementarreaktionen der Radiolyse. Für den Gesamtvorgang wurde eine Gleichung erster Ordnung gefunden, selbst bei Verwendung einer mikrokristallinen Monomerform. Das Sättigungsphänomen der Polymerausbeute konnte nur bei Zusatz von H2O und sym. Dichloraceton zum Monomeren beobachtet werden.
    Notizen: The elementary reactions in the radiation-induced polymerization of 3,3-bis-chloromethyloxetane in solid state were investigated by mass spectrometry and gas phase chromatography. Gaseous and other by-products of the polymerization were measured. Gases evovled with γ-ray irradiation were H2, CO, and CO2. It was suggested that the G value of the active centers of polymerization is far lower than that of the other elementary reactions of the radiolysis. The overall process was found to follow a first order rate equation even with a monomer of micro-crystalline form. The saturation phenomena of polymer yield could only be observed on addition of water and sym-dichloroacetone to the monomer.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 102 (1967), S. 39-46 
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Es wurde der Einfluß von mehreren anorganischen Verbindungen auf die strahleninduzierte Polymerisation von 3,3-Bis-chlormethyloxetan untersucht. Einige Stoffe erhöhten die Reaktionsgeschwindigkeit des verunreinigten Monomeren, nicht aber die des reinen Monomeren.Die Ergebnisse der Polymerisation des reinen Monomeren zeigen, daß 1. die Anzahl der Polymerenketten unabhängig von der Natur der zugegebenen Verbindung konstant ist, 2. die Bruttopolymerisationsgeschwindigkeit und die Viskositätszahl des Polymeren mit der Bestrahlungsdauer zunehmen. Aus diesen Ergebnissen wird geschlossen, daß die Wirkung der zugegebenen Verbindungen darauf beruht, daß eine durch die Verunreinigungen verursachte Abbruchreaktion unterdrückt wird.
    Notizen: The effects of solid additives on the radiation-induced polymerization of 3,3-bis-(chloromethyl) oxetane were studied. Some of the additives which acelerate the polymerization rate of the unpurified monomer, showed no effect with the purified monomer. The results obtained with the pure monomer, showed, that (1) the number of polymer chains under the same conditions was independent of the kind of solid additive, and was constant; (2) the rate of polymerization and the intrinsic viscosity of the polymer increased with irradiation time. From these results, it was concluded that the role of the additive was to depress a termination reaction by trapping the poison for polymerization.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 37 (1959), S. 353-362 
    ISSN: 0022-3832
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: A novel high polymerization of ethylene by Al-TiCl4 catalyst is studied. The polymer yield increases with higher TiCl4 concentration and with larger amount of Al metal used. With an Al/TiCl4 mole ratio larger than 10, the conversion slightly decreases. The highest conversion is gained at 180°C., and higher reaction temperatures decrease remarkably the yield of solid polymer. The molecular wight of polymers increases with the Al/TiCl4 ratio, but it remains constant at Al/TiCl4 ratios larger than 3. It is highest at 180°C. With respect to the Al/TiCl4 mole ratio, the melting point has a relation similar to that of the molecular weight. It is also maximum at 180°C. The rate equation is determined by some kinetic studies, obtaining the formula -dP/dt = 4.37 [TiCl4] exp{-4800/RT}P for a certain range of reaction conditions. A possible cationic mechanism for this polymerization is suggested.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    ISSN: 0022-3832
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The high polymerization of ethylene and propylene is studied by a novel catalyst which consists of metals and metal halides. Titanium halides with metallic aluminum, magnesium, or zinc are able to accelerate the polymerization of ethylene to produce a high polymer at 50-250°C. and under the pressure of 1-200 atoms. In the presence of metallic aluminum, the activity of titanium halides descreases with the valency of titanium. The effect of milling of metals in titanium halide solution is also studied. This treatment is found to lower the rate of reaction. An extremely high molecular polyethylene is synthetized by an appropriately chosen mixed halides catalyst. Polyethylene produced has melting point ranging from 120-135°C., molecular weight being as high as some hundreds of thousand. Tensile strength is 100-250 kg./cm.,2 specific gravity is 0.94-0.95. The number of CH3 groups as well as of C—C double bonds in small and crystallinity is considerably higher than high pressure polyethylene. This catalyst is also applied to the polymerization of propylene. A solid polypropylene melting at 140-155°C. is produced.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    ISSN: 0022-3832
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The polymerization of ethylene initiated by 2,2,-azobisisobutyronitrile in water was studied at 70-120° C. and at 100-1500 kg./cm.2 pressure. The following relations between the reaction conditions and the properties of polyethylene produced were obtained (1) the density decreases with temperature, and (2) the molecular weight increases with pressure, independent of the amount of initiator. The reaction begins with an incubation period for which the overall rate Ri is represented by Ri = const. × I0P0, in which I0 and P0 are the amount of initiator used and the initial pressure, respectively. In the main period of reaction the overall rate was found to be R = k′I0 exp {-αt}P1.8. A reaction mechanism is proposed from which this rate equation can be derived. The proposed mechanism implies that the deactivation and the termination of radicals is first order with respect to the radical concentration.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 45 (1960), S. 305-312 
    ISSN: 0022-3832
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: A theory related to the molecular size distribution and gel point in the polymerization by successive formation of terfunctional interunit junctions is presented. This type of polymerization may be realized in three-dimensional networks containing isocyanuric and s-triazine rings from polyisocyanate and polynitrile compounds, respectively. The gel point is obtained as αcrit equals; 1/2(f - 1), while in the polymerization due to bifunctional interunit junction it had been given by Flory and Stockmayer as αcrit equals; 1/(f - 1), where αcrit is the fraction of reacted groups at the gel point and f is the number of functional groups borne by a monomeric unit.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Letters 3 (1965), S. 871-873 
    ISSN: 0449-2986
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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