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  • 1
    Electronic Resource
    Electronic Resource
    Emulsion co- and terpolymerization of styrene, methyl methacrylate, and methyl acrylate. I. Experimental determination and model prediction of composition drift and microstructure in batch reactions (1996)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 34 (1996), S. 935-947 
    Details
    ISSN: 0887-624X
    Keywords: emulsion copolymerization ; terpolymerization ; composition drift ; chemical composition distribution ; gradient polymer elution chromatography ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In Part I of this series the reactivity ratios of the comonomer pair methyl acrylate-methyl methacrylate were determined with low-conversion bulk polymerizations. It was shown that the binary reactivity ratios of the systems styrene-methyl acrylate, styrene-methyl methacrylate, and methyl acrylate-methyl methacrylate describe composition drift in low-coversion bulk terpolymerizations with these monomers reasonably well. A computer model was developed to simulate the composition drift in emulsion co- and terpolymerizations. The composition drift in two batch emulsion copolymerization systems (styrene-methyl acrylate and methyl acrylate-methyl methacrylate) and one emulsion terpolymerization system (styrene-methyl acrylate-methyl methacrylate) was investigated both experimentally and with the model. Experimental results were compared with model calculations. The copolymer chemical composition distributions (CCD) were determined with gradient polymer elution chromatography (GPEC®). This technique was also used for the first time to obtain information about the extent of composition drift in emulsion terpolymerizations. Cumulative terpolymer compositions were determined with 3H-NMR as a function of conversion and with this information the three-dimensional CCD was obtained. The composition drift was analyzed with respect to free radical copolymerization kinetics (reactivity ratios) and monomer partitioning. It was shown that in most emulsion copolymerizations the composition drift is mainly determined by the reactivity of the monomers and to a lesser extent by monomer partitioning, except in systems where there is a large difference in water solubility. The model predictions for cumulative terpolymer composition as a function of conversion and the three-dimensional terpolymer CCD showed excellent agreement with the experiments. The GPEC® elution chromatogram of the terpolymer was found to be in accordance with the predicted CCD and the experimentally determined CCD. © 1996 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 2
    Electronic Resource
    Electronic Resource
    Emulsion co- and terpolymerization of styrene, methyl methacrylate and methyl acrylate. II. Control of emulsion terpolymer microstructure with optimal addition profiles (1996)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 34 (1996), S. 949-955 
    Details
    ISSN: 0887-624X
    Keywords: emulsion terpolymerization ; control of microstructure ; monomer addition profile ; chemical composition distribution ; gradient polmer elution chromatography ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An optimal addition profile for the preparation of a chemically homogeneous emulsion terpolymer of styrene, methyl methacrylate, and methyl acrylate was determined using a recently developed model for describing composition drift in emulsion co- and terpolymerizations. TRISEPS, described in Part I of this series. The model uses recently published simplified equations to describe monomer partitioning and the terminal model for describing terpolymer composition. The optimal addition rate profile was determined from the calculated optimal addition profile with a purely empirical and iterative method. With gradient polymer elution chromatography (GPEC®) the homogeneity and/or heterogeneity of the terpolymers prepared in the iterative series of experiments could be determined and compared to the heterogeneity of the corresponding batch terpolymer described in Part I. It was shown that a homogeneous terpolymer could be obtained indicating that the simplified equations for monomer partitioning and the terminal model for terpolymer composition describe the system adequately. It was also shown that GPEC® was useful in the determination of the optimal addition rate profile. © 1996 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
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