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  • 1
    Electronic Resource
    Electronic Resource
    A high-pressure cell for optical microscopy and measurements on the phase diagram of poly(diethylsiloxane) (1998)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 69 (1998), S. 1823-1827 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A new high-pressure cell as useful equipment for a polarizing microscope is described. Measurements in a temperature range between −40 and +270 °C under hydrostatic pressures up to 300 MPa allow for example the observation of polymer morphology and phase transitions. In addition to a documentation on video and photograph, respectively, the computer-controlled light intensity measurement offers the possibility of a quantitative analysis. Investigations on the phase diagram of poly(diethylsiloxane) have been carried out and show, that the transition temperature from mesophase to isotropic melt decreases with increasing pressure for pressures above 160 MPa. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1148848
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  • 2
    Electronic Resource
    Electronic Resource
    Motion of segment dislocations as a model for glass relaxation (1982)
    Springer
    Polymer bulletin 7 (1982), S. 413-416 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The meander model of polymer melts assumes nearly parallel packing of molecular chains and therefore invites to describe shear deformation processes by “dislocation” motion in analogy to metals. Examination of the glass relaxation data for 12 amorphous polymers leads to reasonable values for the energy and the Burgers vector of segment dislocations which are also consistent with thermal properties of the glass transition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00266735
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  • 3
    Electronic Resource
    Electronic Resource
    Eine niedermolekulare Modellsubstanz für lineares Polyäthylen. Vorschlag des „Kinkenmodells“ zur Deutung des γ- und α-Relaxationsprozesses (1963)
    Springer
    Colloid & polymer science 189 (1963), S. 14-22 
    Details
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Zusammenfassung Aus Schubmodulmessungen an linearem Polyäthylen werden die Aktivierungsenergien der drei Dispersionsgebiete α,β, γ bestimmt. Zur Deutung desα und γ Relaxationsprozesses wird ein Baufehlermechanismus vorgeschlagen. Experimentelle Untersuchungen an Paraffinmischungen (komplexer Schubmodul und röntgenographische Messungen) erhärten diese Vorstellung.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01500283
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  • 4
    Electronic Resource
    Electronic Resource
    Versetzungstheorie des Schmelzens auf der Grundlage der Cluster-Entropie-Hypothese (CEH) (1982)
    Springer
    Colloid & polymer science 260 (1982), S. 248-257 
    Details
    ISSN: 1435-1536
    Keywords: phase transition ; dislocation theory of melting ; cluster-entropy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Abstract As a model for the melting of densely packed atomic crystals (as well as for the “true” melting of molecular and polymer crystals) the formation of tilt boundaries by dislocation loops inside a “melt-grain” with parallel glide planes is proposed. The dislocation arrangement is allowed to fluctuate in time and in space (from grain to grain). Taking lines of atoms (atomic dislocations) perpendicular to the tilt boundaries as statistical elements, and using the cluster-entropy-hypothesis (CEH), a cooperative treatment of the melt-transition and of the defect-contribution to the thermal properties as well as an estimate of the activation energy of the viscosity are achieved.
    Notes: Zusammenfassung Für das Schmelzen dichtgepackter Atomkristalle (und auch für die „eigentliche“ Schmelzumwandlung von Molekül- und Polymerkristallen) wird die Bildung von Wänden aus Versetzungsringen in einem „Schmelzkorn“ paralleler Gleitebenen vorgeschlagen. Diese Versetzungsstruktur kann zeitlich und räumlich (von Korn zu Korn) fluktuieren. Mit Atomreihen senkrecht zu den Versetzungswänden (Atomversetzungen) als statistischen Elementen und aufgrund der Cluster-Entropie-Hypothese (CEH) gelingt eine kooperative Behandlung der Schmelzumwandlung und des Defektanteils der thermischen Eigenschaften sowie eine Abschätzung der Aktivierungsenergie der Viskosität.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01447961
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  • 5
    Electronic Resource
    Electronic Resource
    Phase behavior and elastic properties of a slightly crosslinked liquid crystalline main-chain polymer (1990)
    Springer
    Colloid & polymer science 268 (1990), S. 222-229 
    Details
    ISSN: 1435-1536
    Keywords: Liquidcrystallinepolymers ; crosslinkedpolymers ; mechanicalproperties ; rubber-likeelasticity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A liquid crystalline main-chain polymer was slightly crosslinked by a reaction withα, ω-difunctionalized oligo-siloxanes. Crosslinking does not disturb the liquid crystalline phases, which are identified by x-ray measurements as smecticB and smecticA phases. Measurements of the elastic properties of the crosslinked sample show rubber-like elasticity, even in the liquid crystalline phases. A difference of 7 K was found between cooling and heating for the smecticA/isotropic transition from DSC and mechanical measurements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01490246
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  • 6
    Electronic Resource
    Electronic Resource
    Laudatio (1990)
    Springer
    Colloid & polymer science 268 (1990), S. 597-597 
    Details
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01410398
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  • 7
    Electronic Resource
    Electronic Resource
    Dielectric relaxation of rod-like labels in polyisoprene (1992)
    Springer
    Colloid & polymer science 270 (1992), S. 219-228 
    Details
    ISSN: 1435-1536
    Keywords: Dielectric measurements ; label ; polyisoprene ; glass process ; rod-likemolecules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Rod-like molecules with a strong dipole in the long axis were mixed with synthetic polyisoprene (IR305) in low concentrations (0.1–5 wt%) and measured dielectrically in the frequency range 10−2–106 Hz and the temperature range −60°–0°C (glass relaxation range). The measurements showed an additional symmetrical relaxation process slower than the glass process by a factor ranging from 10 to 100 times, depending on the length and structure of the label. The label relaxation process was characterized by a narrow distribution of relaxation times and its strong coupling with the segmental motion. For the labels with only a longitudinal dipole moment, no relevant part of the label relaxation was observed in the relaxation frequencies of the glass process; this may be attributed to the parallelism and compactness of the polyisoprene chains. In contrast, the labels with an additional vertical dipole component showed an additional relaxation process superimposed on the glass relaxation with also almost the same distribution of relaxation times. The slow label relaxation could be attributed to a diffusion or rotational diffusion relaxation process through a multistep relaxation mechanism determined by the segmental motion of the matrix.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00655473
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  • 8
    Electronic Resource
    Electronic Resource
    Meander model of polymer melts and networks (1987)
    Springer
    Colloid & polymer science 75 (1987), S. 23-44 
    Details
    ISSN: 1435-1536
    Keywords: Shear compliance ; mechanical relaxations ; polymer melts ; polymer networks ; meander model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract After reviewing the basic ideas of the meander model together with a short comparison with the coil model, the mechanical relaxation processes in polymer melts – fractions and mixtures — are discussed. This is done by decomposition of master curves of the dynamic shear-compliance into (a) glass relaxation with its plateau complianceJ eN, (b) the shearband process δJ B ∞ and the rearranged shearband process δJ B 0 , and finally (c) flow relaxation and viscous flow. It will be shown how crosslinking decreases the relaxation strengthsJ eN and δJ B 0 .
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01188356
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  • 9
    Electronic Resource
    Electronic Resource
    Relaxation of label molecules in polyisoprene (1986)
    Springer
    Colloid & polymer science 264 (1986), S. 185-188 
    Details
    ISSN: 1435-1536
    Keywords: Label molecules ; dielectric relaxation ; polyisoprene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01414848
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  • 10
    Electronic Resource
    Electronic Resource
    The high temperature transition of polyethylene into a Condis phase, described on the basis of the cluster-entropy hypothesis (CEH) (1986)
    Springer
    Colloid & polymer science 264 (1986), S. 415-422 
    Details
    ISSN: 1435-1536
    Keywords: Condis phase ; high temperature transition of polyethylene ; cluster-entropy hypothesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract On the basis of atomistic calculations a rotator model of the high temperature Condis phase of polyethylene is proposed. Its cooperative statistical treatment (using CEH for the lateral packing of chains) explains the first order transition from the all-trans crystal as well as the transition dataT t ,ΔS t ,ΔV t . We found that the normal melting (i. e. at pressures below the triple point) is also governed by the onset of the Condis phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01419545
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