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  • 1
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 1487-1506 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A mathematical model for describing the particle size distribution (PSD) in emulsion copolymerization system is developed by analogy to that in emulsion homopolymerization system as proposed by Lichti and co-workers. By use of the appropriate combinations of the kinetic parameters of the comonomers, the complicated equations for copolymerization systems can be reduced to simpler equations identical to those of homopolymerization systems. The two calculation examples, styrene-methyl methacrylate and styrene-butadiene systems, are given to demonstrate the applicability of the proposed theory. The conditions for producing bimodal PSD from a seeded emulsion polymerization are discussed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 1143-1155 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In emulsion polymerization, the polymer particles generated exhibit a size distribution. Broadness of the distribution is usually characterized by the uniformity (Dp), a ratio of weight to number average particle sizes, and is found to decrease with reaction time despite the fact that the particle volume distribution is usually broadened. Based on the mathematical model proposed by Lichti, Gilbert, and Napper, detailed analysis using the method of moment shows that standard deviation of the particle volume distribution increases with time, while that of the particle diameter distribution decreases with time. Dp's of both volume and diameter distributions all show decreasing with reaction time. These results are in agreement with those found experimentally. The present analysis indicates that, in the characterization of the broadness of the PSD in the emulsion polymerization, one has to be aware of the difference in meanings among these parameters related to the broadness of the PSD.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 3
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 28 (1990), S. 2857-2866 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: For emulsion polymerization in the zero order region (Interval II) a relation between the average number of free radicals per particle, n̄(t), and the particle number average volume of a particle, v̄n(t), is derived as dv̄n(t)/dt = Kn̄(t), where K is volume growth rate of a particle containing one free radical and is constant. This relation is also extended to copolymerization systems with an appropriate modification of the definition of K. By use of the data of particle size distribution (PSD), n̄ can be calculated without knowing the total number of particles. In conjunction with this relation, the recently developed light-scattering technique for measuring the PSD in addition to the conventional transmission electron microscope technique can provide a quick route for determination of n̄. Styrene and methyl methacrylate emulsion homopolymerizations are taken as calculation examples.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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