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  • 1
    Electronic Resource
    Electronic Resource
    Statistical thermodynamics of polydisperse polymer systems in the framework of lattice fluid model: Effect of molecular weight and its distribution on the spinodal in polymer solution (2002)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 116 (2002), S. 5892-5900 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: With the aid of thermodynamics of Gibbs, the expression of the spinodal was derived for the polydisperse polymer-solvent system in the framework of Sanchez–Lacombe Lattice Fluid Theory (SLLFT). For convenience, we considered that a model polydisperse polymer contains three sub-components. According to our calculation, the spinodal depends on both weight-average (M¯w) and number-average (M¯n) molecular weights of the polydisperse polymer, but the z-average molecular weight (M¯z) dependence on the spinodal is invisible. The dependence of free volume on composition, temperature, molecular weight, and its distribution results in the effect of M¯n on the spinodal. Moreover, it has been found that the effect of changing M¯w on the spinodal is much bigger than that of changing M¯n and the extrema of the spinodal increases with the rise of the weight-average molecular weight of the polymer in the solutions with upper critical solution temperature (UCST). However, the effect of polydispersity on the spinodal can be neglected for the polymer with a considerably high weight-average molecular weight. A more simple expression of the spinodal for the polydisperse polymer solution in the framework of SLLFT was also derived under the assumption of υ*=υ1*=υ2* and (1/r10)−(1/r2i0)→(1/r10). © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1424320
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  • 2
    Electronic Resource
    Electronic Resource
    Pressure dependence of the miscibility of poly(vinyl methyl ether) and polystyrene: Theoretical representation (1997)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 107 (1997), S. 2597-2602 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The present calculations were performed on the basis of the Sanchez-Lacombe-Balasz lattice fluid theory. The two system specific parameters cursive-epsilon12* and δcursive-epsilon* required for that purpose have been obtained from the spinodal temperatures measured (SANS) for mixtures of poly(vinyl methyl ether) (PVME) and deuterated polystyrenes (d-PS) by Schwahn and coworkers. The experimental data reported for atmospheric pressure and six representatives of the present system are well described theoretically, where cursive-epsilon12* does not depend on molar mass and δcursive-epsilon* decreases only slightly as the chain length of d-PS is raised. The measured pressure influences on the spinodal conditions correspond to an approximately linear reduction of δcursive-epsilon* with increasing P; this observation should reflect the volume changes associated with the formation of specific interactions. According to the present calculations the critical composition shifts markedly towards pure PVME as P is raised. Since experimental data are commonly expressed in terms of the Flory-Huggins theory, the current results were also translated into Flory-Huggins interaction parameters and evaluated with respect to the contributions of enthalpy and of entropy. The agreement between experimental information and that calculated from the Sanchez-Lacombe-Balasz lattice fluid theory is reasonable. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.474571
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  • 3
    Electronic Resource
    Electronic Resource
    Tensile and transformational behavior of poly(ether sulfone)/polycarbonate blends (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 243 (1996), S. 1-10 
    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: Polyethersulfon/Polycarbonat-Blends wurden durch Schmelzemischen hergestellt und mit Dichtemessungen, Zugversuchen, Differentialkalorimetrie, dynamisch-mechanischer Analyse und Transmissionselektronenmikroskopie (TEM) untersucht. Die Resultate zeigen, daß die Blends aus zwei Phasen bestehen; eine zwischen den beiden Phasen gebildete Grenzflächenschicht wurde durch TEM nachgewiesen. Die untersuchten Blends zeigen eine Synergie zwischen Reißdehnung und Zugmodul. Die Abhängigkeit der mechanischen Eigenschaften von der Zuggeschwindigkeit wurde für Blends mit unterschiedlichen PES/PC-Gewichtsverhältnissen diskutiert.
    Notes: Blends of a poly(ether sulfone) (PES) and a polycarbonate (PC) were prepared by melt-mixing and were studied by tensile tests, differential scanning calorimetry, dynamic mechanical analysis, density measurements and transmission electron microscopy (TEM). The blends were found to be two-phase systems and an interfacial layer was presumed to be formed between two phases, which was verified by TEM. A synergism of elongation at break and tensile modulus was shown in PES/PC blends. The effects of the crosshead speed on the mechanical properties were discussed for blends with different PES/PC weight ratios.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1996.052430101
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  • 4
    Electronic Resource
    Electronic Resource
    Periodic radial growth in ring-banded spherulites of poly(ε-caprolactone)/poly(styrene-co-acrylonitrile) blends (1998)
    Weinheim : Wiley-Blackwell
    Macromolecular Rapid Communications 19 (1998), S. 131-133 
    Details
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The isothermal crystallization process of a PCL/SAN blend (90/10 wt.-%) was investigated by using real time image analysis and hot stage optical microscopy. It was found that the growth rate of ringbanded spherulites in the isothermal crystallization process is not constant. Slow growth occurs in the bright bands, while fast growth is found in the dark bands. The radially unequal growth rate of ring-banded spherulites in PCL/SAN blends may be related to the convex band structure on the surface. This new discovery gives us the idea that rhythmic growth is effective in the growth process of ring-banded spherulites.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Statistical thermodynamics of polydisperse polymer blends with strong interaction (1993)
    Basel : Wiley-Blackwell
    Die Makromolekulare Chemie, Theory and Simulations 2 (1993), S. 263-268 
    Details
    ISSN: 1018-5054
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A statistical thermodynamics theory of polydisperse polymer mixtures with strong interaction between dissimilar components based on a lattice fluid model is formulated. Expressions for the free energy, equation of state, phase stability and spinodal for a polydisperse, binary polymer mixture with strong interaction are derived.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mats.1993.040020208
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  • 6
    Electronic Resource
    Electronic Resource
    Mechanical properties and miscibility of polyethersulfone/phenoxy blends (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 59 (1996), S. 1843-1847 
    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: The blends of polyethersulfone and phenoxy were prepared by melt mixing in a Brabenderlike apparatus. The specimens for measurements were made by compression molding and then were water-quenched at room temperature under pressure. The tensile strength, tensile modulus, elongation at break and yield, density, thermal analysis, and dynamic mechanical properties were each measured. The dependence of tensile strength, tensile modulus, elongation at break and yield, and density on composition was obtained. The relationship between tensile modulus and elongation at break and yield and speed of the crosshead at different weight ratios of the blends is shown. The effects of composition and miscibility on the mechanical properties are discussed. © 1996 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Statistical thermodynamics in the framework of the lattice fluid model, 2Part 1: cf. ref.(22). Binary mixture of polydisperse polymers of special distribution (1994)
    Weinheim : Wiley-Blackwell
    Macromolecular Theory and Simulations 3 (1994), S. 751-780 
    Details
    ISSN: 1022-1344
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In this paper, the Gibbs free energy, the equation of state and the chemical potentials of polydisperse multicomponent polymer mixtures are derived. For general binary mixtures of polydisperse polymers, we also give the Gibbs free energy, the equation of state and the chemical potentials and derive the stability criteria and spinodal. Furthermore, binary polydisperse polymer mixtures of special distribution, i.e., Flory distribution, uniform distribution and Schulz distribution, are discussed and the influence of polydispersity on the interaction energy parameter is considered. For these special-distribution systems, the spinodal curves are simulated and the influence of chain length and polydispersity on the spinodal curves is discussed. The results suggest that the spinodal temperature of the mixture with a given volume fraction of one component decreases with increasing polydispersity and the extent of the shift decreases with increasing degree of polymerization when η = M̄w/M̄n is given. In addition, the variations of the spinodal curves with polydispersity and chain length are shown and they are qualitatively compared with the experimental results.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mats.1994.040030410
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  • 8
    Electronic Resource
    Electronic Resource
    Statistical thermodynamics in the framework of the lattice fluid model, 1. Polydisperse polymers of special distribution (1994)
    Weinheim : Wiley-Blackwell
    Macromolecular Theory and Simulations 3 (1994), S. 743-750 
    Details
    ISSN: 1022-1344
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Gibbs free energies and equations of state of polymers with special molar mass distributions, e.g., Flory distribution, uniform distribution and Schulz distribution, are derived based on a lattice fluid model. The influence of the polydispersity (or the chain length) on the close-packed mass density, the close-packed volume of a mer and the mer-mer interaction energy or the scaling temperature is discussed. The diagrams of the Gibbs free energies as a function of temperature and chain length are simulated with a computer. The results suggest that a polydisperse polymer is thermodynamically more stable than the corresponding monodisperse polymer and that the thermodynamical properties of a polydisperse polymer are identical with those of the corresponding monodisperse polymer when the average degree of polymerization is sufficiently high.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mats.1994.040030409
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  • 9
    Electronic Resource
    Electronic Resource
    Statistical thermodynamics in the framework of the lattice fluid model, 3Part 2: cf. ref.(20). Binary mixture of polydisperse polymers of special distribution with strong interactions (1994)
    Weinheim : Wiley-Blackwell
    Macromolecular Theory and Simulations 3 (1994), S. 781-793 
    Details
    ISSN: 1022-1344
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: For a binary mixture of polydisperse polymers with strong interactions, the free energy, the equation of state, the chemical potentials and the spinodal are formulated on the basis of the lattice fluid model. Further, the spinodal curves for the system with strong interactions are simulated by using mixtures of special-distribution polymers, i.e., Schulz distribution and uniform distribution. From comparison with the experimental results, it can be seen that the shift of the spinodal curves with the polydispersity and the strong-interaction energy parameter is qualitatively identical with the conclusions of Nishi and Kwei, and Goh, Paul and Barlow.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mats.1994.040030411
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  • 10
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    Point-to-set dynamic length scale in binary Lennard-Jones glass-formers (2017)
    American Institute of Physics
    Details
    Publication Date: 2017-09-21
    Print ISSN: 0021-9606
    Electronic ISSN: 1089-7690
    Topics: Chemistry and Pharmacology , Physics
    Published by American Institute of Physics
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