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  • Industrial Chemistry and Chemical Engineering  (1)
  • ddc:000  (1)
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  • 1
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An automatic stirred tank reactor of laboratory scale has been developed for on-line measurement of conversion, viscosity, and molar mass distribution of homogeneous polymerizations. For these on-line measurements, a fraction of the reaction mixture is bypassed through a densimeter and a viscometer. Samples are taken at intervals of 15 min, diluted semi-automatically, and then injected into a high performance gel permeation chromatograph for determination of the molar mass distribution of the polymers. A microcomputer collects the measured data, calculates the monomer conversion and the output data for different control units. In this study, methyl methacrylate is polymerized batch- and semi-batchwise with ethyl acetate as solvent and in the presence of different initiators. The semi-batch polymerizations are carried out at constant reaction rate by feeding the initiator and at a given increase in viscosity by feeding the solvent.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Publication Date: 2014-02-26
    Description: Modeling of free radical polymerization leads to very large and usually stiff systems of ordinary differential equations which cannot be solved directly in an efficient way. This paper presents the application of a new approach called discrete Galerkin method to a realistic example - the polymerization of methyl methacrylate(MMA). The method is characterized by a Galerkin approximation on the basis of orthogonal polynomials of a discrete variable which represents the polymer degree. It allows the efficient computation of solutions of complete kinetic schemes with time- or moment-dependent reaction coefficients by reducing the complexity to a few differential equations. The approximation error can be controlled by an error estimation. In the case of MMA polymerization a reduction of computational effort by a factor of about 25 compared to a standard method can be obtained for the quasi-steady-state approximation of the model. In addition solutions of the instationary kinetic scheme can be easily computed.
    Keywords: ddc:000
    Language: English
    Type: reportzib , doc-type:preprint
    Format: application/pdf
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