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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 37 (1989), S. 487-498 
    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: A screening study of the solubility of poly(1,1-difluoroethylene) (PVF2, M̄w = 2 × 105) at room temperature in a wide variety of dipolar aprotic species has facilitated the discovery of a series of new solvents (N-methyloxazolidone, cyclic-substituted ureas) and rationalization of the data in a two-dimensional solubility map involving their dipole moment, μ, and their hydrogenx-bond-accepting (HBA) power β (Taft solvatochromic parameter). This map may be used as a predictive tool for the research of new functional classes of solvents, such as N-substituted mixed amideester of phosphoric acid or N-substituted sulfurous diamides. The variations of the intrinsic viscosity of the polymer with solvent polarity may be quantitatively analyzed using a linear multiparametric correlation which emphasizes the two opposite contributions of cavitation effects (Hildebrand solubility parameter δ) and of polymer-solvent interactions (β) on the coil expansion: [η] (dL.g-1) = 0.792 - 1.2 × 10-3δ2(J.cm-3) + 1.59 β. Finally, 1,3-dimethyl-2-oxo-hexahydropyrimidine (N,N′-dimethylpropylene urea) leads to the highest value of the refractive index increment (dn/dc = -0.065 mL.g-1 at λ = 632 nm), and thus appears as the best solvent for light-scattering measurements.
    Additional Material: 3 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 30 (1992), S. 1103-1111 
    ISSN: 0887-6266
    Keywords: sorption of water in poly(ammonium sulfopropylbetaines) ; poly(ammonium sulfopropylbetaines), DSC hydration process in ; polyzwitterions, water sorption in ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The hydration of four amorphous acrylic and methacrylic poly(zwitterions) bearing the ammonium sulfopropylbetaine function as a side-groups () was studied by differential scanning calorimetry over broad ranges of temperature (150-400 K) and water content (weight fraction W1 〈 0.5). Analyses were made of the first-order transitions and heat capacity of sorbed water, glass transition temperature (Tg) measurements. Nonfreezable bound water, about 7.7 ± 0.9 mol/monomeric unit, behaves as a single phase: Its mobility, fairly similar to that of bulk liquid water in viscoelastic systems at T 〉 250 K, decreases with temperature in the glassy systems, but never disappears, even at 185 K. The depression of the glass transition temperature of the hydrated polymers obeys Couchman's equation: Tg = Σi Wi ΔCpi Tgi / Σgi WiΔCpi. Freezable bound water, about 6.7 ± 0.9 mole/monomeric unit, shows multipeak melting endotherms in the range 242-272 K. Because of their charged sites, the hydration process of the poly(zwitterions) appears more similar to that of poly(electrolytes) than to that of uncharged hydrophilic polymers. © 1992 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 30 (1992), S. 1113-1121 
    ISSN: 0887-6266
    Keywords: sorption of water in poly(ammonium sulfopropylbetaines) ; poly(ammonium sulfopropylbetaines), sorption isotherms for water in ; polyzwitterions, water sorption in ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Water sorption by four amorphous acrylic and methacrylic poly(zwitterions) bearing ammonium sulfopropylbetaine side groups () was studied at a constant temperature of 23°C and over a broad range of water activity (0.14-0.90). Whatever the physical state of the hydrated polymer, glassy or viscoelastic, water diffusion is Fickian (average diffusion coefficient D̄s in the range 2-16 × 10-8 cm2 s-1), and the sorption isotherms may be quantitatively analyzed according to the Guggenheim-Anderson-De Boer amended BET equation for multilayer sorption processes. The number of sitebound water molecules per monomeric unit is in the range 1.5-2.0, and apparently there is no great energy difference between direct site binding and indirect binding in the successive solvation layers. The polymer-water interaction parameter (-0.6 〈 χ Flory 〈 0.6) is an increasing function of the water content of the hydrated poly(zwitterions) over the whole composition range (water volume fraction 〈 0.5), without any clear transition from the glassy to the viscoelastic state. Clustering of water molecules (Zimm-Lundberg theory) is never observed, even at high water content. Because of the charged structure of their dipolar units, the poly(zwitterions) show a water sorption process similar to that of the corresponding poly(electrolytes) of the tetra-alkylammonium sulfonate type. © 1992 John Wiley & Sons, Inc.
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  • 4
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 33 (1995), S. 2033-2043 
    ISSN: 0887-6266
    Keywords: sorption of water in poly(ammonioalkoxydicyanoethenolates) ; polyzwitterions ; water sorption in ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Water sorption by amorphous (meth)acrylic poly(zwitterions)-bearing quaternary ammonioalkoxydicyanoethenolate side groups , dipole moment μ(D) = 25.9 and 30.8 for p = 2 and 3, respectively was studied at 23°C over a broad range of water activity a (0.14-0.98). Water diffusion is nearly Fickian (Ds = 5.9 10-7 cm2.s-1 for a = 0.63) and the sorption isotherms may be quantitatively analyzed according to the Guggenheim-Anderson-De Boer equation for a multilayer process characterized by a number of site-bound water molecules per monomeric unit, nm ⋑ 0.7. The Flory χ interaction parameter is a strongly increasing function of the water content in the glassy hydrated systems and it always remains higher than 0.75. Clustering of water molecules (Zimm-Lundberg theory) is never observed. Differential scanning calorimetry allows to quantify nonfreezable bound water (type I) of strong plasticization efficiency, n(I) = 2.8 mol. of water per monomeric unit, and it points out the quasisimultaneous emergence of low amounts of freezable bound water (type II) crystallizing at -40°C and melting at -1°C and of bulkfree water (type III, n(II)/n(III) ⋑ 0.1). All these typical features distinguish these rather hydrophobic poly(zwitterions) from their hydrophilic homologues of the quaternary ammoniopropanesulfonate type . © 1995 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 11 (1973), S. 233-237 
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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