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  • 1
    Electronic Resource
    Electronic Resource
    Changes in the reactivity of functional groups during polyesterification: A new approach to polymerization in fatty-acid-modified polyesters (alkyd resins) (1967)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 11 (1967), S. 1593-1602 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    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: Gel-point calculations based on the theory of polyesterification proposed by Flory do not agree with the experimental values even when Bobalek's concept of gel point as the first formation of infinite molecules (microgel) is used. Resins covering the range 30-60% oil length were prepared and examined by electron microscopy for the presence of microgel particles. The extent of reaction at which microgel forms is discussed in relation to the concept of equal reactivity. The conditions necessary for the formation of microgel particles and the significance of these observations to the basic assumptions used in developing the theory of polyesterification are discussed.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1967.070110820
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Reactions catalyzed by minerals. Part II. Chain termination in free-radical polymerizationsProd. No. 1653 (1967)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 11 (1967), S. 2567-2575 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    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: The influence of aluminosilicates and magnesium silicates on the free-radical polymerization of methyl methacrylate is discussed. The relationship between the structure of the mineral and its ability to inhibit radical reactions is considered, and it is concluded that aluminum in octahedral coordination is mainly responsible for the inhibition. Mechanisms which account for the termination reaction are proposed and supported by studies of the reaction of stable free radicals with the minerals.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1967.070111216
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Reaction of α, α-diphenyl-β-picrylhydrazyl with acids (1965)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A: General Papers 3 (1965), S. 3107-3116 
    Details
    ISSN: 0449-2951
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The action of dilute aqueous mineral acids on α,α-diphenyl-β-picryl hydrazyl (DPPH) has been studied and shown to result in the rapid loss of the characteristic color of the radical. Hydrobromic and hydrochloric acids yield α,α-diphenyl-β-picryl hydrazine (DPPH-H) and the corresponding halogen-substituted α,α-diphenyl-β-picryl hydrazine. Hydroiodic acid gives DPPH-H, iodine, and a small quantity of DPPH. A number of organic acids cause similar reactions. Kinetic studies on the hydrobromic acid system indicate that the reaction is first-order with respect to: hydrogen ion concentration, DPPH concentration, and anion concentration. The ability of the anion to undergo one-electron transfer and to dimerize are also important, and the strongest nucleophile gives the fastest reaction. A mechanism which involves ionic attack is proposed to account for the reaction of DPPH with acid. The limitations of DPPH in studying reaction mechanisms are then discussed in relation to the proposed ionic mechanism.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1965.100030906
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    Paper (German National Licenses)
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