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  • 1
    Electronic Resource
    Electronic Resource
    A phenomenological master curve for viscosity - structure data for two phase polymer systems in simple shear flow (1983)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 610-613 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: A master curve hypothesis is established based on a mass balance and an assumption of continuous stress through interfaces for well dispersed two phase systems with “defined” zero shear viscosity. The master curve, which is in reasonable accordance with experimental data is represented in a double logarithmic plot of log (ηT/T,0) against log \documentclass{article}\pagestyle{empty}\begin{document}$ \left({\frac{{\eta _{T,0} M_C H\rho}}{{c^2 RT}}\dot \gamma _T} \right) $\end{document}. Mc is the molecular weight between entanglements, H = M̄w/M̄n, ρ is the density, c is the polymer concentration, all defined for the continuous phase. ηT and ηT,0 are the viscosity and zero shear viscosity of the blend, ηT is the apparent shear rate, R the gas constant, and T is absolute temperature.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760231104
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  • 2
    Electronic Resource
    Electronic Resource
    Phase transitions during shear flow of two phase polymer blends. II. Styrene-acrylonitrile/poly(methylmethacrylate) transition to “Homogeneous” melt state (1987)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 27 (1987), S. 351-358 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: An advanced hypothesis derived in Part I (this issue) is tested with selected model blends. Blends of copolymers of styrene and acrylonitrile (SAN) and poly(methylmethacrylate), (PMMA) were studied because they are both amorphous, thermally stable, have large density differences, are easy to cut (in an ultramicrotome) and because comprehensive studies have been reported In the literature on this system. The melt viscosity of the blends were studied using a Rheometrics Mechanical Spectrometer and an Instron capillary rheometer. Light scattering measurements were performed during flow in order to measure the critical transition stress. The phase structure of quenched samples was studied by transmission electron microscopy on ultramicrotome cuts. It was shown that an Interpenetrating co-continuous structure develops when flow is stopped, if a homogeneous phase Is formed during flow. Melt fracture limits the applicability of this approach to nearly compatible blends.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760270508
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Melting of crystallites in polymers with low degree of crystallinity under shear flow conditions I: Poly(vinyl chloride) (1974)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 14 (1974), S. 342-351 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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 aggregates found in dilute solutions of nearly atactic PVC have been shown to consist of 10 to 15 single molecules held together by a crystalline nucleus. Based on the postulate that the last crystallites in a PVC melt have the same structure as found in dilute solution, a relation between the melting temperature in shear (Tdyn), the static melting temperature (Tm) and the shear stress (τ) is found: \documentclass{article}\pagestyle{empty}\begin{document}$$ {1 \mathord{\left/ {\vphantom {1 {T_{{\rm dyn}} }}} \right. \kern-\nulldelimiterspace} {T_{{\rm dyn}} }} - {1 \mathord{\left/ {\vphantom {1 {T_m }}} \right. \kern-\nulldelimiterspace} {T_m }} = \frac{{\tau ^2 }}{{Q \cdot T_{{\rm dyn}} ^2 }} $$\end{document} where Q is a constant. The model predictions are in accordance with data from a Brabender rheometer and a Rheometrics mechanical spectrometer. Q is found to be a constant for samples with weight average molecular weights in the interval between 70,000 and 160,000 corresponding to polymerization temperatures between 40 and 70°C.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760140507
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  • 4
    Electronic Resource
    Electronic Resource
    The viscosity of monomolecular melts of poly(vinyl chloride) (1976)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 20 (1976), S. 2497-2509 
    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: PVC melts are predicted to be homogeneous with single molecules as the stable flow units (monomolecular melts) at corresponding values of high temperatures and/or high shear stresses. Under these conditions, it is found that the zero shear viscosity in simple shearing flow of rigid compounds depends on the average molecular weight by weight to the 3.5 power for molecular weights between 24,000 and 100,000. All data measured under conditions where monomolecular melts are predicted fall on a master curve of reduced viscosity versus reduced shear rate when a relaxation time proportional to η0/c2T is used. It is, therefore, concluded that monomolecular melts of PVC compounds follow the same structure-viscosity relations as found for other linear melts in viscometric flow.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1976.070200918
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    Paper (German National Licenses)
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