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  • 1
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 35 (1988), S. 2193-2200 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Polymerization of methyl methacrylate (MMA) using Ce(IV) as initiator in aqueous nitric acid solution in the presence of sodium lauryl sulphate (NaLS) has been studied kinetically at a temperature range of 25-35°C. The rate of polymerization (Rp) increases with increasing concentration of NaLS, and it was also proportional to [MMA]2; but, in the presence of NaLS, the change of Rp with respect to [Ce(IV)] and [H+] were not linear and similarly the rate of Ce(IV) disappearance was not proportional to its original concentration. The overall activation energy of the polymerization process in presence of 0.01M NaLS was found to decrease by ∼ 7.0 kcal mol-1. The monomer-micelle association constant has been calculated to be 5.135 × 104 mol-1 L. The polymer obtained in surfactant medium is sparingly soluble in benzene and DMSO. From infrared spectra clear evidence of vinyl polymerization was obtained.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 62 (1996), S. 19-25 
    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 acrylonitrile (AN) using the Ce(IV)-citric acid (CA) redox system as an initiator in aqueous nitric acid solution, in the presence of an anionic surfactant, sodium dodecyl sulfate (SDS), has been kinetically studied at a temperature range of 25-45°C. The rate of polymerization (Rp) and disappearance of Ce(IV) (-Rce) increase with increasing concentration of SDS, above its critical micelle concentration (cmc), when the surfactant molecules are organized. Rp was found to be proportional to [AN]1.5 and [CA]0.5. With other organic substrates, Rp follows the increasing order of sorbitol ≥ mannitol 〉 glycerol 〉 CA. But it was found to decrease considerably in the presence of cationic surfactant (CTAB), and nonionic surfactant (Triton-X-100) had no effect on the rate. -Rce varies linearly with [Ce(IV)] and [CA]. Both Rp and -Rce increase with increasing temperature. The overall activation energy was found to be 18.31 and 13.72 kcal/mol in the absence and presence of 0.015M SDS, respectively. The chain length of the polyacrylonitrile has also increased with increasing SDS concentration. © 1996 John Wiley & Sons, Inc.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 27 (1982), S. 3859-3866 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Micellar catalyzed polymerization of acrylonitrile using ceric(IV)-glycerol redox system in aqueous sulfuric acid solution in the presence of sodium lauryl sulfate (NaLS) has been studied. The polymerization experiments were conducted between 15°C and 25°C, under conditions where no oxidation of sodium lauryl sulfate by ceric ion would we expected. The rate of polymerization (Rp) increases with increasing concentration of NaLS. The rate of monomer (AN) disappearance was proportional to [AN]1.5 and [glycerol]0.5, but, however, Rp changes in a nonlinear manner with increase in Ce(IV) concentration in the presence of the surfactant. The rate of Ce(IV) disappearance was not proportional to its original concentration. The chain length of the polymer could not be determined viscometrically, as the polymer obtained in presence of NaLS was insoluble in organic solvents. The activation energy of this polymerization process was calculated by conducting the experiment at different temperatures. The infrared spectra of the polymers in the presence and absence of surfactant have also been examined.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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