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  • 1
    Electronic Resource
    Electronic Resource
    Theoretical description of phase separation in flowing polymer solutions (1980)
    Basel : Wiley-Blackwell
    Die Makromolekulare Chemie, Rapid Communications 1 (1980), S. 231-234 
    Details
    ISSN: 0173-2803
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/marc.1980.030010409
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  • 2
    Electronic Resource
    Electronic Resource
    Phenylalkanes as theta-solvents for polystyrene (1982)
    Basel : Wiley-Blackwell
    Die Makromolekulare Chemie, Rapid Communications 3 (1982), S. 17-21 
    Details
    ISSN: 0173-2803
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/marc.1982.030030104
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  • 3
    Electronic Resource
    Electronic Resource
    On the factors governing the pressure dependence of the viscosity of moderately concentrated polymer solutionsPart of theses of H. G. and J. R. S. (1982)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 27 (1982), S. 1277-1291 
    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: Viscosity measurements were carried out as a function of pressure and temperature with solutions of polystyrene in eight (endothermal) θ-solvents at the respective critical composition by means of a Searle-type apparatus. A rolling-ball viscometer was used for the investigation of the pure solvents. In all cases the viscosity coefficient increases in a more or less exponential manner when the pressure is raised. For θ-conditions, the volumes of activation of the solutions exceed that of the pure solvent by typically 10-15%. The exact amount of this extra efffect stemming from the presence of the polymer and its variation with temperature can be qualitatively correlated with the heats of mixing. The ratio of the viscosity of the solution at 1000 and 1 bar, respectively, can be varied for a given solvent power (θ-temperature) by the choice of the solvent from ca. 2 (cyclopentane) to 4 (trans-decalin). Within a given system, the maximum effects that can be realized by a change of the solvent power via the variation of temperature ranges from ca. 3 to 6 (tert-butylacetate).
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1982.070270417
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  • 4
    Electronic Resource
    Electronic Resource
    Oligomer-oligomer incompatibility, 3.Part 2: cf. Ref.2. End-group effectsDedicated to Professor G. V. Schulz on the occasion of his 75th birthday (1981)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 182 (1981), S. 1801-1818 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In order to investigate the influences of different end-groups on oligomer miscibility with other substances, oligo(propylene glycol)s bearing —OH groups (OPG-OH) studied in the previous paper2, were acetylated at both ends (OPG-AC). The limits of miscibility of OPG-AC with oligo(dimethylsiloxane) (ODMS) were measured turbidimetrically. A simple and reliable method for the determination of the critical points from turbidity data is presented. The observed upper critical temperatures (Tc) increase with degree of oligomerization of ODMS (ranging from 1 to 5), whereas Tc shows a minimum when the degree of oligomerization of the OPG-AC is raised (from 1 to 57,5). For lower mol. wt. oligoglycols, the Tc-values of ODMS/OPG-AC are lower by ca. 50 K as compared with those of ODMS/OPG-OH. The different end-groups play a minor role with respect to the pressure influences (up to 1 500 bar the miscibility increases in all cases). For OPG-AC the chain length of optimum miscibility with a given ODMS is found at considerably lower values than for OPG-OH. The theoretical evaluation of the experimental material on the basis of the lattice theory yields a reduction in the enthalpies of mixing up to 10% and an increase in the volumes of mixing (〈0) up to 50% when —OH is replaced by —AC. For the treatment of end-group effects, the solubility parameter theory, when combined with the concept of molar attraction constants, presents several advantages: In particular it is possible to describe the phase separation behaviour of the different oligomer mixtures simply by means of solubility parameters and molar volumes of the different segments and end-groups and to forecast the presence or absence of a chain-length of optimum miscibility.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1981.021820620
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  • 5
    Electronic Resource
    Electronic Resource
    Rheological studies of moderately concentrated polystyrene solutions. I. A new method for the extrapolation of the zero-shear viscosity (1983)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 21 (1983), S. 1205-1216 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Measurements of the viscosity coefficient η of solutions of polystyrene (Mw = 6.0 × 105 and 1.77 × 106) in trans-decalin (TD, θ solvent) and toluene (TL, good solvent) as function of shear rate (11-104 s-1), concentration (4.24-11.21 wt %), and temperature (10-50°C) are reported. As a new theoretically grounded method for the determination of the zero-shear viscosity η0 it is proposed to plot η as a function of $\left({\eta \dot \gamma} \right)^3$. The intercepts of the straight lines obtained by this procedure give η0 in good agreement with directly measured values.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1983.180210719
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  • 6
    Electronic Resource
    Electronic Resource
    Rheological studies of moderately concentrated polystyrene solutions in the vicinity of the θ temperature. II. Shear-rate dependence for different thermodynamic conditions (1983)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 21 (1983), S. 1217-1226 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The viscosity data of moderately concentrated polystyrene solutions in trans-decalin (TD) (θ solvent, θ temperature 21°C) and toluene (TL) (good solvent) reported in Part I are discussed in terms of Graessley's entanglement theory. Under good solvent conditions, Graessley's master curve provides an excellent fit up to high shear rates, whereas in the vicinity of the θ conditions the data have to be modified by a parameter ηfric introduced by Ito and Shishido. The characteristic time of mechanical response to flow of chains approximately given by the shift factor τ0 is found in good solvents to be on the order of the Rouse relaxation time. In poor solvents, close to demixing, τ0 tends to much higher values, indicating a reduced chain mobility. The influence of temperature on the viscosity decreases with increasing shear. The resulting apparent energy of activation of flow shows very small or even negative values at high shear rates. This behavior can be explained by the modified Graessley theory, however, in a quite natural way.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1983.180210720
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  • 7
    Electronic Resource
    Electronic Resource
    High temperature demixing of poly(decyl methacrylate) solutions in isooctane and its pressure dependenceHerrn Prof. Dr. H.-J. Cantow mit den besten Wünschen zum 60. Geburtstag gewidmet. (1983)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 184 (1983), S. 1303-1309 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Solutions of poly (decyl methacrylate) in isooctane (2,2, 4-trimethylpentane) show lower critical solution temperatures (LCST) that lie well below the thermal degradation of the polymer. The corresponding exothermal theta-temperature (from the Shultz-Flory plot) amounts to 210°C. The increase in solvent quality by pressure turns out to be very pronounced (d Tc/dp ≈ +1 K/bar). With solutions of the polymer in motor oils, high temperature demixing is unlikely to occur below their boiling point. The theoretical evaluation of published experimental data for 11 different systems exhibiting LCSTs demonstrates the following: Under the equilibrium vapour pressure of the solution high temperature demixing is generally observed withing the temperature interval between Tb, the boiling point of the pure solvent (1 bar), and 1,5 Tb. As Tc - Tb increases, the heats of mixing and the pressure influence on Tc increase, too.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1983.021840621
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  • 8
    Electronic Resource
    Electronic Resource
    Vapour pressures of the system tert-butyl acetate/polystyrene (1984)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 185 (1984), S. 2161-2167 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: An apparatus is presented for the precise measurement of vapour pressures. It is tested with diethyl ether and applied to the system tert-butyle acetate/polystyrene (weight-average molecular weight Mw = 110000) up to polymer concentrations of ca. 60 wt.-% in the temperature range from 10 to 90°C; by means of the Redlich-Kister equation the results can well be described analytically. The data are evaluated to yield the Flory-Huggins parameter in the subsequent article in conjunction with other experimental information.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1984.021851011
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  • 9
    Electronic Resource
    Electronic Resource
    Non-newtonian flow behaviour of poly(decyl methacrylate) solutions (1983)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 184 (1983), S. 2539-2551 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The viscosity of solutions of poly(decyl methacrylate)s, PDMA, in 1-pentanol (thermodynamically poor solvent) and in toluence or isooctane (good solvents) was measured up to shear rates of 3 · 104s-1 by means of rotational viscosimeters. The observed pronounced shear thinning is for all solutions well described by the theory of Graessley, with the extension, introduced by Ito. Two parameters, resulting from the evaluation of the flow curves on the basis of the above theory, are discussed: τ0, a characteristic relaxation time of the polymer chain, is found to be in the range of ms. ηfric, a frictional parameter, independent of shear rate, amounts upto 50% of the zero-shear viscosity for the measured solutions. Both, τ0 and ηfric, increase with decreasing solvent quality, increasing molecular weight, and increasing concentration, in accord with theory. A comparatively sharp downward bend, separating two power-law regimes, shows up with moderately concentrated solutions, as the shear rate exceeds about 103 to 104 s-1. This transition is tentatively interpreted as an orientation of the long side chains of PDMA.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1983.021841214
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  • 10
    Electronic Resource
    Electronic Resource
    Concentration dependence of the Flory-Huggins parameter at different thermodynamic conditions (1984)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 185 (1984), S. 2169-2181 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: By means of data from critical demixing and vapour pressure measurements and by inverse gas chromatography, including the results of published light scattering measurments, a consistent picture is obtained for the entire dependence of the Flory-Huggins parameter χ on the weight fraction w2 of the polymer and on the temperature T for the system tert-butyl acetate/polystyrene. Within the entire T-range (ca. 0°C - 140°C), χ increases stronger than exponentially with w2, the rise being the larger the larger χH (the enthalpy contribution to χ) becomes in the limit of infinite dilution. At sufficiently high temperatures (≳ 50°C), χH changes its sign from negative to positive as w2 is raised. This behaviour, as well as the general shape of χ(w2) is in qualitative accord with the results of the corresponding-states theory as developed by Flory et al.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1984.021851012
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