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  • 1
    Electronic Resource
    Electronic Resource
    Ceric ion-initiated polymerization of acrylonitrile in the presence of polyols (1977)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 178 (1977), S. 639-648 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The polymerization of acrylonitrile was studied in aqueous sulfuric acid with the redox initiator system, ceric ammonium sulfate/glycerol at 15-25°C. The initiation was effected by the ceric ion and the radical produced from the reaction of Ce4+ with glycerol. At lower concentrations of Ce4+, the rate of monomer disappearance was proportional to [M]1,5, [G]0,5, and [Ce4+]0,5, and the rate of ceric ion disappearance was directly proportional to [Ce4+] and [G]. The results were explained by a kinetic scheme involving the oxidation of substrate by Ce4+ to give the primary radical and further reaction of the latter with Ce4+ to give the final product, and initiation of polymerization both by Ce4+ and the primary radical. The initiation by Ce4+ was found to be negligible as compared to that by the primary radical. The termination step is postulated to be mutual at lower concentrations of Ce4+ and linear at higher concentrations of Ce4+. The induction period and the rate of polymerization was compared with those of other polyol systems, such as sorbitol and mannitol.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1977.021780301
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  • 2
    Electronic Resource
    Electronic Resource
    Kinetics of inhibited or retarded polymerization. Investigations on the cerium(IV)/toluene/acrylonitrile system (1979)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 953-958 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The kinetics and mechanism of the inhibiting action of toluene on the Ce(IV) initiated polymerization of acrylonitrile were studied together with the effects of [M], [Ce(IV)], [Toluene], [HClO4], [NaClO4], and [Acetic acid] on the rate of polymerization. The values of composite rate constant kkt/kpkoki for toluene (and substituted toluenes) was calculated by plotting [M]/Rp versus [M]-1. A very significant observation in the present study was that the plot of [M]/Rp versus [M]-1 gave a negative intercept, which seems to be a general observation for all inhibiting substrates. On the basis of the experimental data, it could be concluded that the benzyl radical obtained by hydrogen abstraction, and not a chain transfer, is responsible for the inhibition.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1979.021800411
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  • 3
    Electronic Resource
    Electronic Resource
    Vinyl polymerisation of acrylonitrile by the vanadium(V)-glycerol redox system (1976)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 177 (1976), S. 2709-2719 
    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: Gegenstand dieser Arbeit ist die Untersuchung der Kinetik der durch das Redoxsystem V5+ -Glyzerin angeregten thermischen Polymerisation von Acrylnitril in Gegenwart von Schwefel- oder Perchlorsäure im Temperaturbereich von 35-45°C. Polymerisationsgeschwindigkeit und die Geschwindigkeit des V5+ -Verbrauchs wurden hinsichtlich ihrer Abhängigkeit von der Zeit, der Monomer-, Metallion-, Glyzerin- und Säurekonzentration sowie der Ionenstärke untersucht. Die experimentellen Ergebnisse stützen einen Mechanismus, der einen Start über freie Radikale vorsieht, die aus dem Zerfall eines acyclischen V5+ -Glycerin-Komplexes resultieren. Die kinetischen Befunde sind mit der Annahme eines linearen Abbruchs (1. Ordnung bezüglich der Radikalketten) bei höheren V5+ -Konzentrationen vereinbar. Die verschiedenen Geschwindigkeits- und Aktivierungsparameter wurden ermittelt und ein geeignetes Reaktionsschema vorgeschlagen. Die in diesem System auftretenden Induktionsperioden und Polymerisationsgeschwindigkeiten wurden mit den entsprechenden für andere Polyhydroxy-Systeme (Mannit, Sorbit) registrierten Größen vergleichen.
    Notes: A kinetic study of the thermal polymerisation of acrylonitrile initiated by the redox system V5+ -glycerol in sulfuric acid and perchloric acid was made in the temperature range 35-45°C. The rates of polymerisation and V5+ disappearance wee measured with respect to their dependence on time, monomer, metal ion, glycerol, acid, and ionic strength. Experimental evidences provide support to a mechanism involving initiation by a free radical produced by the decomposition of the acyclic complex between V5+ and glycerol. The kinetics are consistent with a linear termination of polymerisation (1st order in respect of growing radicals) at higher concentration of V5+. The various rate and activation parameters were evaluated and an appropriate reaction scheme is proposed. The induction period and the polymerisation rate of the V5+ -glycerol system were compared with those involving polyhydroxy alcohol systems such as sorbitol and mannitol.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1976.021770913
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  • 4
    Electronic Resource
    Electronic Resource
    Mechanism of the polymerization of acrylamide initiated by the glycerol/Ce(IV) redox system (1977)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 178 (1977), S. 1971-1977 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The mechanism of the polymerization of acrylamide in aqueous medium initiated by the glycerol (R)/Ce(IV) redox system was studied. The rate of monomer disappearance was found to be directly proportional to [M]3/2, and R1/2 at lower concentrations of Ce(IV). The rate of the disappearance of ceric ions was found to be inversely proportional to [M] and directly proportional to [Ce(IV)] and [R]. Consistent with the findings of earlier investigations, a complex formation between monomer, acrylamide, and ceric ion is indicated. The experimental results show the termination to be mutual. On the basis of these and other kinetic results, an appropriate mechanism is proposed. At higher concentration of Ce(IV), a different mechanism seems to operate. The rates of disappearance of both the monomer and ceric ions are retarded on addition of anions like HSO4-, SO4- -, or CIO4-, but they are accelerated on the addition of Mn(II) ions. Interpretations of the above observations are furnished.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1977.021780711
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  • 5
    Electronic Resource
    Electronic Resource
    Substituent parameters for radical reactions: Cerium(IV)-substituted acetophenones-acrylonitrile system (1979)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 17 (1979), S. 3859-3866 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The present investigation describes a new approach for the determination of radical substituent parameters σ. The technique has been developed by an ingenious combination of two equations, one proposed by Yamamoto and Otsu and the other by Streitwieser and Perrin. The σ values for different substituents were first evaluated by application of this newly developed technique to the Ce(IV)-substituted toluenes-acrylonitrile system. The validity of these values was then tested by application to another system, the Ce(IV)-substituted acetophenones-acrylonitrile system, which is the subject of the present study.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1979.170171206
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  • 6
    Electronic Resource
    Electronic Resource
    Substituent effects in polymerization reactions in terms of generalized substituent constants F and R and generalized weighting factors f and r (1980)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 47-51 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this investigation an approach to correlate the composite rate constants of some redox polymerization reactions [acrylonitrile-Ce(IV)-organic substrate] with a new type of multiparameter equation is described. The multiparameter equation is based on Swain and Lupton's F and R, the field and resonance components of the substituents, respectively, and the unique positional weighting factors f and r suggested by Williams and Norrington. The statistical parameters of the correlation involving the substituent constants (fF and rR) and the rate data have been found to be quite satisfactory, the average coefficient of determination being 0.91. The significance levels of the correlation also indicate that the present model is applicable to the kinetics of redox polymerization. The sign and magnitude of the reaction-dependent regression constants α and β suggest that three different types of reaction mechanisms are operative for the substrates benzaldehyde, phenylthiourea, acetophenone, and toluene.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1980.170180104
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  • 7
    Electronic Resource
    Electronic Resource
    Vinyl polymerization: Kinetics of Ce(IV)-acetophenone-initiated polymerization of acrylonitrile in acetic-sulfuric acid mixtures (1978)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 16 (1978), S. 391-397 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polymerization of acrylonitrile (M) initiated by the Ce(IV)-acetophenone (AP) redox pair has been studied in acetic-sulfuric acid mixtures in a nitrogen atmosphere. The rate of polymerization is proportional to [M]3/2, [AP]1/2 and [Ce(IV)]1/2. The rate of disappearance of ceric ion,-RCe, is proportional to [AP], [M], and [Ce(IV)]. The effect of certain salts, solvent, acid and temperature on both the rates have been investigated. A suitable kinetic scheme has been proposed, and the composite rate constants kp 2(k/k/t) and k0/ki are reported.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1978.170160209
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