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  • 1
    Electronic Resource
    Electronic Resource
    Über die druckabhängigkeit der viskoelastischen und physikalisch-chemischen eigenschaften von polymeren, 2.Teil 1: cf.14. Spezifisches volumen und thermische ausdehnung einiger polymeren beim schmelzen und kristallisieren (1977)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 178 (1977), S. 2037-2047 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Measurements of specific volumes are described as function of temperature and pressure of melting or crystallizing linear polyethylene, isotactic polypropylene, and polyoxymethylene. A pressure range of 50 to 1600 bar permits determination of relative volume changes as function of temperature and pressure. Pressure influence on melting points, temperature hysteresis between melting and crystallization and their volume changes as well as the thermodynamic driving force of phase change have been investigated. Clausius-Clapeyron's equation permits calculation of heats of crystallization.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1977.021780718
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  • 2
    Electronic Resource
    Electronic Resource
    Über die druckabhängigkeit der viskoelastischen und physikalisch-chemischen eigenschaften von polymeren, 3.Teil 2: cf.2. Darstellung des druckeinflusses auf das spezifische volumen im technischen temperatur- und druckbereich (1977)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 178 (1977), S. 2649-2659 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A reduction formula for the calculation of the specific volume v at any temperature T and any pressure P is derived; it consists of the two equations: \documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} {v = {{\left( {v_0 + \zeta \cdot \Delta {\rm P}} \right)} \mathord{\left/ {\vphantom {{\left( {v_0 + \zeta \cdot \Delta {\rm P}} \right)} {\left( {1 + \xi \cdot \Delta P} \right)}}} \right. \kern-\nulldelimiterspace} {\left( {1 + \xi \cdot \Delta P} \right)}}} \\ {T_0 = T - \psi \cdot \Delta P} \\ \end{array}$$\end{document} The parameters ξ, ζ and ψ can be easily calculated from values in the literature, and therefore only a volume-temperature curve at atmospheric pressure has to be measured.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1977.021780916
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  • 3
    Electronic Resource
    Electronic Resource
    Einfluß des temperns auf die negative thermische ausdehnung von polyethylen (1981)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 182 (1981), S. 1787-1799 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The linear thermal coefficient of expansion for high density polyethylene, extended to draw ratios λ = 8 to 16 is α = -24·10-6 K-1 at 20°C. This value results from the orientation of crystallites with an expansion coefficient αc = -12·10-6 K-1 and from stresses in the amorphous phase. Using the model of series coupling of crystalline and amorphous parts the value αam ≤ -50·10-6 K-1 is calculated for a crystallinity xv = 70%. From measurements of Young's modulus the fraction of tie-molecules χtie = 0,4% of the sample is assessed and the expansion coefficient αtie = -90·10-6 K-1. Annealing of the samples leads to shrinkage while the density ρ increases slightly and the expansion coefficient α increases considerably. Samples annealed at temperatures closely below the melting point show a slight decrease of the density at 20°C but a value of α exceeding that of isotropic samples. This effect can be explained by preferred orientation of the crystal a-axis in fibre direction as soon as orientation starts to break down.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1981.021820619
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  • 4
    Electronic Resource
    Electronic Resource
    Differentialthermoanalytische untersuchungen bei verschiedenen drücken an einer molekulargewichtsreihe von polyethylenoxiden (1981)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 182 (1981), S. 3311-3322 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Melt- and crystallization-temperatures were measured of poly(ethylene oxide)s with increasing molecular weight and at various pressures up to 5 000 bar by differential thermal analysis (DTA). Both these temperatures increase with pressure and display a different molecular weight dependence below and above M ≈ 3 000. A similar behaviour is shown by the melt enthalpies, constants a and c of the Simon-equation and by the undercooling ΔT.The transition from a zig-zag- to a helix-structure found by various authors changes to higher molecular weights with pressure, whereas chain folding does not depend upon pressure. The pressure coefficient of the melting temperature and the undercooling as well as the chemical potential are investigated as functions of the molecular weight for poly(ethylene oxide).
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1981.021821134
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  • 5
    Electronic Resource
    Electronic Resource
    Über die druckabhängigkeit der viskoelastischen und physikalisch-chemischen eigenschaften von polymeren, 6.Teil 5: V.-H. Karl, F. Asmussen, F.-P. Wolf, K. Ueberreiter, Ber. Bunsenges. Phys. Chem. 81, 598 (1977). Anwendung der reduktionsformel auf amorphe polymere (1978)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 179 (1978), S. 1125-1129 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1978.021790427
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  • 6
    Electronic Resource
    Electronic Resource
    Über die Druckabhängigkeit der viskoelastischen und physikalisch-chemischen Eigenschaften von Polymeren, 7.Teil 6: cf.: V.-H. Karl, Makromol. Chem. 179, 1125 (1978). Einfluß des Lösungsmittels para-Xylol auf das Schmelzen und Kristallisieren von Polyethylen (1978)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 179 (1978), S. 1601-1608 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Melting and crystallization of polyethylene (PE) with various amounts of xylene is investigated by pressure dependent volume-temperature curves. These can be calculated by a reduction formula described earlier. Flory's formula for lowering of the melting point of polymers by solvents proves to be applicable also for high pressures.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1978.021790619
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  • 7
    Electronic Resource
    Electronic Resource
    Über die druckabhängigkeit der viskoelastischen und physikalisch-chemischen eigenschaften von polymeren, 8. Die viskosität von polyethylen bis 5000 bar (1979)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 79 (1979), S. 11-19 
    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: A new high pressure viscosimeter is described which permits rheological investigations up to 5000 bar and 200°C. The dependence on pressure and shear rate of the apparent viscosity of polyethylene is measured at 130, 155, and 190°C. Newtonian viscosity is calculated according to the method of Spencer and Dillon, its pressure coefficient decreases with pressure; crystallization induced by flow causes the pressure coefficient to increase abnormally. Free volume decreases in quite the same way as the pressure coefficient when pressure raised. From the slope of the log ηs-PM-curve can be concluded that the pressure coefficient of non-Newtonian flow decreases with increasing pressure and shear rate.
    Notes: Ein neues Hochdruckkapillarviskosimeter wird beschrieben, mit dem rheologische Eigenschaften von Polymeren bis zu einem Druck von 5000 bar und einer Temperatur von 200°C untersucht werden können. Die scheinbare Viskosität von Hochdruck-Polyethylen wird in Abhängigkeit von Druck und Schergeschwindigkeit für 130, 155 und 190°C ermittelt. Anhand der durch das Extrapolationsverfahren nach Spencer und Dillon erhaltenen Newtonschen Viskosität wird gezeigt, daß der Druckkoeffizient der Newtonschen Viskosität mit dem Druck abnimmt; bei Auftreten einer scherinduzierten Kristallisation steigt dieser jedoch sehr stark an. Mit dem Druckkoeffizienten nimmt auch das zum Fließen notwendige freie Volumen mit dem Druck ab. Anhand der Steigung der log ηs,-PM,-Kurve wird festgestellt, daß der Druckkoeffizient der scheinbaren Viskositat im nicht-Newtonschen Bereich sowohl mit steigendem Druck als auch mit steigender Schergeschwindigkeit abnimmt.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1979.050790102
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  • 8
    Electronic Resource
    Electronic Resource
    Einfluß der herstellungsbedingungen auf E-modul und dichte von HD-polyethylen. I. Variation des druckes (1979)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 79 (1979), S. 21-35 
    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: Young's modulus and density of samples, made from high density polyethylene at various pressures up to 1500 bar, have been measured. The samples were crystallized at a cooling rate of 1,14 K/min. All measurements have been carried out at ambient pressure and room temperature. Young's modulus and density are shown to increase with higher values of pressure during crystallization of the material. The increase of Young's modulus with increasing density cannot be described by the wellknown dependence of modulus on the degree of crystallinity. For this reason a relationship has been derived taking into account permanent stresses in the amorphous regions of the samples. By means of this formula agreement between measured values of Young's modulus and density could be achieved.
    Notes: E-Modul und Dichte wurden an Proben aus HD-Polyethylen gemessen, die bei verschiedenen Drucken bis 1500 bar nicht-isotherm mit einer Abkühlrate von 1,14 K/min hergestellt worden waren. Die Messungen erfolgten bei Atmosphärendruck und Raumtemperatur. Sowohl E-Modul als auch Dichte steigen mit zunehmendem Herstellungsdruck an. Der Anstieg des E-Moduls mit zunehmender Dichte läßt sich aber nicht durch die bekannte Abhängigkeit vom Kristallisationsgrad beschreiben. Deshalb wird unter der Annahme von Verspannungen im amorphen Bereich eine Formel abgeleitet, die den hier gemessenen Zusammenhang von E-Modul und Dichte bestätigt.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1979.050790103
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  • 9
    Electronic Resource
    Electronic Resource
    Einfluß der herstellungsbedingungen auf E-modul und dichte von HD-polyethylen. II. Variation der kristallisationsgeschwindigkeit (1979)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 79 (1979), S. 37-54 
    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: Young's modulus and density of samples, made from high density polyethylene, have been measured. The samples were processed under pressure of 1 500 bar by means of nonisothermal and isothermal crystallization varying the rates of crystallization. All measurements have been carried out at ambient pressure and room temperature. Density is shown to decrease linearly with increasing logarithm of the rate of crystallization. Young's modulus is falling towards a minimal value with increasing rate of crystallization, but rising again at even higher rates. This rise being at variance with the wellknown decrease of the modulus with lower density (crystallinity) is explained by means of internal stresses of the samples. Consequences of thermodynamical and structural causes of the internal stresses are discussed.
    Notes: E-Modul und Dichte wurden an Proben aus HD-Polyethylen gemessen, die mit verschiedenen Kristallisationsgeschwindigkeiten nicht-isotherm und isotherm unter dem konstanten Druck 1500 bar hergestellt worden waren. Die Messungen erfolgten bei Atmosphärendruck und Raumtemperatur. Die Dichte nimmt mit dem Logarithmus der Kristallisationsgeschwindigkeit linear ab. Der E-Modul fällt mit zunehmender Kristallisations-geschwindigkeit bis zu einem Minimum, um dann wieder anzusteigen. Dieser Anstieg, der im Widerspruch zu der bekannten Abnahme mit abnehmender Dichte (Kristallisationsgrad) steht, wird durch Verspannungen in den Proben erklärt. Die Auswirkung von thermodynamischen und strukturellen Ursachen der Verspannungen wird diskutiert.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1979.050790104
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  • 10
    Electronic Resource
    Electronic Resource
    Untersuchung der negativen thermischen Ausdehnung von verstrecktem Polyethylen (1980)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 92 (1980), S. 89-106 
    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: The linear thermal coefficient of expansion α of high density polyethylen has been determined for temperatures between -15 and +50°C. Isotropic samples yield values of about α = 120 · 10-6 K-1 at 20°C depending on the degree of crystallinity. The values can be calculated from αam = 230 · 10-6 K-1 for amorphous and αkr = 90 · 10-6 K-1 for totally crystalline material. Drawing of samples to ratio λ = 8 to 16 leads to α = -24 · 10-6 K-1 parallel to the fibre axis, whereas for the c-axis of crystals αc = -12 · 10-6 K-1 is found. On basis of a two-phases-model one calculates αam = -52 · 10-6 K-1 for the oriented amorphous phase. This can be explained by entropy elastic behaviour of the stressed tie-molecules. In contrast to this the thermal expansion of volumes both of drawn and isotropic samples is about equal.
    Notes: Der linear thermische Ausdehungskoeffizient α von Polyethylen hoher Dichte wurde für Temperaturen von etwa -15 bis +50°C bestimmt. Bei isotropen Proben erhält man für T0 = 20°C Werte um 120 · 10-6 K-1, die sich je nach Kristallisationsgrad aus den Ausdehnungskoeffizienten αam = 230 · 10-6 K-1 der amorphen und α;kr = 90 · 10-6 K-1 der kristallinen Phase ergeben. Proben mit Verstreckungsgraden λ = 8 bis 16 haben in Faserrichtung α = -24 · 10-6 K-1, während man für Kristallite in Richtung der c-Achse αc = -12 · 10-6 K-1 findet. Ausgehend von einem Zweiphasen-Modell erhält man für die orientierte amorphe Phase etwa αam = -52 · 10-6 K-1. Dies wird auf entropieelastisches Verhalten der gespannten tie-molecules zurückgeführt. Dagegen ist die Volumenausdehnung für verstreckte und isotrope Proben etwa gleich.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1980.050920108
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