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  • 1
    Electronic Resource
    Electronic Resource
    α-olefin oligomers and polymers with metallocene catalystsDedicated to Prof. Dr. rer. nat. Dr.-Ing. E. h. Hansjörg Sinn on the occasion of his 65th birthday (1995)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 227 (1995), S. 159-177 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Metallocen-Katalysatoren eröffnen neue Wege zur Synthese von Olefinoligomeren und -polymeren, deren Molekulargewichte und Schmelzpunkte in weiten Bereichen variieren. Einige wichtige Besonderheiten bei der Herstellung von Oligomeren, von wachsartigen sowie von hochmolekularen Polymeren durch Metallocen-Katalyse werden hier behandelt. Am Beispiel der Oligomerisation von Hexen wird ein einfaches kinetisches Modell entwickelt, das geeignet erscheint, den Reaktionsverlauf und die resultierende Oligomerenverteilung beim Einsatz von Metallocen-Katalysatoren zu beschreiben. Die Herstellung von Propylenpolymeren mit niedrigen und hohen Molekulargewichten durch Metallocen-Katalyse wird hinsichtlich der Reaktionsbedingungen und der Produkteigenschaften mit bekannten Prozessen verglichen. Ferner wurde der Einfluß von verschiedenen Unregelmäßigkeiten der Polymerketten, wie Kettenenden, Regioirregularitäten und Comonomersegmenten auf die Schmelzpunkte untersucht.
    Notes: Metallocenes offer new synthetic routes to olefin oligomers and polymers covering a wide range of molecular weights and melting points. This paper deals with some important features of the preparation of oligomers, wax-like polymers as well as highmolecular-weight polymers via metallocene catalysis. Taking the oligomerization of hexene as an example, a simple kinetic scheme is established, which is suitable to describe the course of the reaction and the resulting oligomer distribution with metallocenes as catalysts. For low and high-molecular-weight polymers, the metallocene route to polypropylene is compared to existent processes in terms of reaction conditions and product properties. An attempt is made to separate the effect of different chain defects like chain ends, regioirregularities and comonomers on the melting point.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1995.052270115
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Optimierung der Produktqualität von Polymeren im Semibatch-BetriebVortrag von CHR.-U. SCHMIDT anläßlich ßThe First ECCEß, 4. Mai 1997 in Florenz (Italien). (1999)
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 71 (1999), S. 832-835 
    Details
    ISSN: 0009-286X
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cite.330710810
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  • 3
    Electronic Resource
    Electronic Resource
    Vergleich von Kalorimetern für die kinetische Untersuchung von PolyreaktionenVortrag von C.-U. SCHMIDT anläßlich des 2. Workshops „Reaktionskalorimetrie“, 4. Apr. 1995 in Frankfurt. (1996)
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 68 (1996), S. 953-958 
    Details
    ISSN: 0009-286X
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cite.330680812
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Absolute propagation rate coefficients in radical polymerization from gel permeation chromatography of polymers produced by intermittent initiation (1997)
    Weinheim : Wiley-Blackwell
    Macromolecular Theory and Simulations 6 (1997), S. 393-426 
    Details
    ISSN: 1022-1344
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The pulsed laser polymerization technique is now a well accepted method to determine propagation rate coefficients for radical polymerization from molar mass distributions resulting from intermittent initiation. A simplified apparatus for the periodic photoinitiation is used which is much less expensive than the laser equipment. The usefulness of the simplified equipment was proved by the determination of kp for styrene at technically relevant temperatures up to 130°C for the first time. Furthermore, careful inspection of the molar mass distribution (mmd) reveals that depending on the reaction conditions, inflection points (Li) can not only be found at integer multiples of kp • to • [M] but also at 0.5i • kp • to • [M], i = 1, 2, 3, … . A rule to find the inflection points leading to correct values for kp is proposed. It is shown that the shape of the mmd inter alia depends on the amount of primary radical termination compared to the termination reaction between growing chains. With dominant primary termination, the maxima of the distribution will give the correct kp, whereas in the absence of primary termination the inflection points should be used. Experimental conditions like initiator concentration, light intensity etc. may influence the position of the Li at least to some extent, and so may give a small but principal error or uncertainty in kp. A new mathematical method for the time-dependent simulation of the resulting mmd is presented which allows the calculations being performed on a PC within an acceptable time.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mats.1997.040060207
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  • 5
    Electronic Resource
    Electronic Resource
    Application of Markov chains to copolymerizationsDedicated to Professor Hiroshi Inagaki on the occasion of his 70th birthday (1995)
    Weinheim : Wiley-Blackwell
    Macromolecular Theory and Simulations 4 (1995), S. 773-800 
    Details
    ISSN: 1022-1344
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Binary copolymerization is treated as a Markov chain process to calculate the distribution of the degree of polymerization for three different copolymerization models. The results for the terminal model according to Melville and Walling show considerable differences compared to the models according to Russo and Munari and Inagaki and Fukuda. Although these latter models start from different assumptions, one considering a penultimate effect in termination reactions, the other one a penultimate effect in propagation reactions, the results for these two models differ only slightly.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mats.1995.040040412
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  • 6
    Electronic Resource
    Electronic Resource
    Study of the nature of radical polymerization of methyl methacrylate with “aged” chromium(II) acetate/benzoyl peroxide (1983)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 184 (1983), S. 1423-1439 
    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 methyl methacrylate (MMA) in DMF with “aged” chromium (II) acetate (Cr(Ac2)) and benzoyl peroxide (BPO), previously formulated as a living radical polymerization, was investigated. The reaction between Cr(Ac)2 and BPO gives besides N-methylformamidomethyl benzoate (3) the N-methylformamidomethylchromium(III) cation (6) as intermediate, which itself may react with BPO with the formation of additional free radicals as compared with the thermolysis of BPO. Thus, the polymerization of MMA in this system could be shown to be a normal radical one with free and uncomplexed radicals. The increase of the degree of polymerization with aging and monomer conversion is explained by the decreasing rate of the radical forming reactions and the onset of the gel effect.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1983.021840710
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  • 7
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    Determination of reactivity ratios for acrylic acid and its dimer from classical parameter estimation and Bayesian approach (2021)
    Details
    Publication Date: 2023-05-12
    Description: The reactivity ratios of acrylic acid (AA, M1) and its dimer beta-acroyloxypropionic acid (diAA, M2) are determined from cumulative copolymerization data by two different methods: classical parameter estimation (PE) by minimizing the objective function and a Bayesian analysis. Classical PE gives r1 =0.74 and r2 = 1.23 at the minimum of the residual. From the Bayesian analysis, the probability distribution of the parameter sets is obtained, revealing the existence of parameter sets with rather the same probability. The influence of the number of data and the size of the measurement error are discussed.
    Language: English
    Type: article , doc-type:article
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  • 8
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    Deterministic and Stochastic Parameter Estimation for Polymer Reaction Kinetics I: Theory and Simple Examples (2021)
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    Publication Date: 2023-05-12
    Description: Two different approaches to parameter estimation (PE) in the context of polymerization are introduced, refined, combined, and applied. The first is classical PE where one is interested in finding parameters which minimize the distance between the output of a chemical model and experimental data. The second is Bayesian PE allowing for quantifying parameter uncertainty caused by experimental measurement error and model imperfection. Based on detailed descriptions of motivation, theoretical background, and methodological aspects for both approaches, their relation are outlined. The main aim of this article is to show how the two approaches complement each other and can be used together to generate strong information gain regarding the model and its parameters. Both approaches and their interplay in application to polymerization reaction systems are illustrated. This is the first part in a two-article series on parameter estimation for polymer reaction kinetics with a focus on theory and methodology while in the second part a more complex example will be considered.
    Language: English
    Type: article , doc-type:article
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