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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Macromolecules 25 (1992), S. 4996-5001 
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Macromolecules 25 (1992), S. 4414-4424 
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 31 (1996), S. 2563-2567 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Hollow spheres of lead zirconate titanate (PZT) [chemical formula Pb(Zr0.52Ti0.48)O3)], with outer diameter of 1–2 mm and a wall thickness of about 100 μm, were fabricated by gellation of a PZT sol inside solid polymer spheres and then burning the polymer out. Monomodally sized polyacrylamide spheres, with diameter 1.40–1.90 mm, were soaked in a PZT sol, prepared by dissolving Pb(NO3)2, zirconiumn-butoxide and titanium isopropoxide inN, N-dimethylformamide. The absorbed sol was then gelled beneath the surface of the polymer sphere by the action of NH3. Upon calcination of the spheres at 850 °C for 4 h in air, hollow spheres of pure PZT perovskite phase (as identified by X-ray diffraction patterns) were obtained. The density of the hollow spheres was 1.13gcm−3, while that of the wall of the spheres was 3.10g cm−3. The scanning electron microscopic examination of the broken spheres showed that the inner surface of the spheres contained rib-like structures, which provided strength to the hollow spheres. The planar coupling factor,k p, of six hollow spheres, placed at a close-packed arrangement in a plane, was 0.22, indicating the possibility of fabrication of low-density transducer arrays.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 32 (1997), S. 4661-4671 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A new sol–gel processing technique has been developed for preparing Nb-doped lead zirconate titanate (PZT) with the composition Pb0.99Nb0.02(Zr0.52Ti0.48)0.98O3. The sol was prepared from Pb(NO3)2, NbCl5, Ti(OC3H7)4 and Zr(C4H9O)4, dissolved in N, N-dimethyl-formamide with stirring at ambient atmosphere. The gel was calcined at 500°C for 30 min and pressed pellets were sintered in air at 1000°C for 2–20 h. The average grain size in the pellets sintered for 4 h was about 1.4 μm, which was smaller than that in undoped PZT pellets. Nb doping decreased angle α in the rhombohedral crystal structure, thereby enhancing electromechanical coupling.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 1817-1827 
    ISSN: 0887-624X
    Keywords: polymer blends ; hydrogen bonding ; miscibility ; phase behavior ; equilibrium constants ; hexafluoroisopropanol groups ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dimensionless equilibrium constants describing the self-association of the hexafluoro-2-alkyl-2-propanol group have been determined from infrared spectroscopic data. Corresponding values of these equilibrium constants for a fully modified polyisoprene containing the hexafluoroisopropanol group (PHFPI) were calculated by taking into account differences in the molar volume of the model and the specific repeat unit of the polymer. Equilibrium constants describing the inter-association of PHFPI with methacrylate, acrylate, and acetoxy type carbonyl groups were obtained from spectroscopic studies of miscible PHFPI blends with poly(n-butyl methacrylate), poly(methyl acrylate), and an ethylene-co-vinyl acetate copolymer containing 70 wt% vinyl acetate. The set of equilibrium constant values were then used to calculate theoretical miscibility windows for the complete range of PHFPI blends with poly(n-alkyl methacrylate)s and four copolymers, ethylene-co-methyl methacrylate, styrene-co-methyl acrylate, ethylene-co-methyl acrylate, and ethylene-co-vinyl acetate. Experimental infrared studies confirm the general validity of the predicted miscibility windows. © 1994 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 2039-2056 
    ISSN: 0887-624X
    Keywords: blends ; hydrogen bonding ; miscibility ; phase behavior ; equilibrium constants ; fluoropolymers ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Theoretical calculations of miscibility windows for binary polymer blends in which one component is an essentially alternating copolymer of tetrafluoroethylene and vinyl alcohol (FVOH) are reported. FVOH has an inherently low solubility parameter [≈ 6.2 (cal. cm-3)0.5] that is outside the range commonly encountered in miscible polymer blends and thus represents a stringent test of the predictive capabilities of an association model we have used in previous work. The application of this model requires that we determine dimensionless equilibrium constants describing the self-association of a model compound 3,4-pentafluorobutan-2-ol (PFB) at 25°C from infrared spectroscopic data. Analogous equilibrium constants for FVOH were scaled from those of PFB by taking into account differences in the molar volume of the model and the specific repeat of the copolymer (see M. M. Coleman, J. F. Graf, and P. C. Painter: Specific Interactions and the Miscibility of Polymer Blends, Technomic, Lancaster, PA, 1991). Equilibrium constants describing the inter-association of FVOH with ester type carbonyl groups were obtained from spectroscopic studies of miscible blends with poly(ethyl methacrylate). These equilibrium constant values were then used to calculate theoretical miscibility windows for the complete range of blends of FVOH with polymethacrylates, ethylene-co-methyl acrylate, styrene-co-methyl acrylate, and ethylene-co-vinyl acetate copolymers. Experimental results performed in our laboratories confirm the general validity of the predicted miscibility windows. © 1993 John Wiley & Sons, Inc.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
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