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  • 1
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 101 (1994), S. 7181-7184 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Direct observation of the percolation-to-cluster transition of an off-critical mixture of polybutadiene and polyisoprene was achieved by optical microscopy. According to optical evidence, the transition occurs in a slow and a fast step not revealed in parallel light scattering experiments.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Macromolecules 25 (1992), S. 3624-3628 
    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
    Polymer bulletin 8 (1982), S. 503-510 
    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 By variable temperature proton enhanced magic angle spinning 13C NMR below Tg individual conformational diads could be resolved for glassy phase segments in semicrystalline erythrodiisotactic poly(1,2-dimethyltetramethylene). An assignment based on γ-shift increments associated with antigauche conformational transitions is given. In addition an improved interpretation of conformational effects in the glassy phase solid state spectrum of amorphous threodiisotactic poly(1,2-dimethyltetramethylene) is presented.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Polymer bulletin 6 (1981), S. 93-100 
    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 first results are reported about the conformational analysis of an amorphous polymer in the glassy state by means of proton enhanced variable-temperature magic angle spinning 13C NMR experiments. In amorphous threodiisotactic poly(1,2-dimethyltetramethylene) at 220 K different conformational diads could be resolved and assigned. From the spectrum of the glassy polymer the shift increment associated with a conformational change of main chain bonds from anti to gauche is determined. In addition the populations of the conformations of CH-CH bonds and of CH-CH-CH2 bond pairs of poly(1,2-dimethyltetramethylene)s are determined in the glassy state and energy differences between these conformations are estimated.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Polymer bulletin 6 (1981), S. 113-119 
    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 chain dynamics of an alternating 1,4-trans-butadiene-propene copolymer has been investigated by high resolution 13C NMR spectroscopy in a broad range of concentrations in solution and in the melt. While in semidilute solution all main chain carbon atoms have the same activation energy of motion it is found that, above a concentration of 20 wt%, the activation energy of the aliphatic carbon atoms increases faster with concentration than the activation energy of the olefinic carbon atoms. It is concluded that in dilute and in semidilute solution all carbon atoms are relaxed by localized transitions about methine-methylene bonds, i. e. the bonds with the lowest energy barrier, whereas in concentrated solution and in the melt the relaxation of aliphatic and olefinic carbon atoms is controlled by independent localized transitions about methylene-methylene and methine-methylene bonds, respectively.
    Type of Medium: Electronic Resource
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  • 7
    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 structure analysis of two conductive polymer systems-poly-4-vinylpyridine and poly(butadiene-b-4-vinylpyridine) with 7,7′,8,8′-tetracyanoquinodimethane (TCNQ)-was done by X-ray diffraction, scanning tunneling microscopy (STM) and FTIR. The charge transfer complex formed between the pyridine group and the known electron acceptor, TCNQ, is supposed to be the conductive element in these systems. In order to understand the structure of this complex, a model compound, the complex of 4-ethylpyridine (4EP) with TCNQ, 4EP/TCNQ2, was studied by the mentioned methods. It appears that there are two crystalline modifications of the model compound with different type of stacks of the TCNQ molecules. In polymer systems only one type of the complex is dominant as revealed by joint analysis of X-ray diffraction diagrams, STM and FTIR data. In the STM image of the polymer surface one can distinguish that molecular stacks with periodicities of 4.1 Å in a row are separated (12.5Å) from each other. Such organization is similiar to the one observed in conductive charge transfer complexes such as tetrathiofulvalene (TTF) with TCNQ. The ordered molecular domains are scattered on the polymer surface and take part in the formation of the conductive network.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 261 (1983), S. 215-223 
    ISSN: 1435-1536
    Keywords: Blockpolymers ; stress relaxation ; interphase ; mechanical models ; equilibrium modulus
    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 Stress relaxation of poly(styrene-b-butadiene-b-styrene) thermoplastic elastomers is studied in dependence of molecular weight and degree of hydrogenation in the temperature range between −30° and +80 °C. The influence of these parameters on the structure of the physical network and the degree of partial mixing in the domain boundary is investigated by separating the stress-relaxation modulus into a viscoelastic term and an equilibrium network modulus calculated from the relaxation-time spectrum. The temperature dependence of the one-second relaxation modulus is quantitatively described by use of a modified Kerner model for the simulation of the viscoelastic term. The modification allows the estimation of the volume fraction of interfacial material and its correlation to the parameters which govern phase separation.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 262 (1984), S. 466-469 
    ISSN: 1435-1536
    Keywords: blockcopolymers ; interphase ; phase separation ; thermodynamic theory
    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 From mechanical model calculations the ratio of domain radius and interfacial thickness in SBS-blockcopolymers is obtained. The results for blockcopolymer systems varying in molecular weight and polymer-polymer interaction parameter are compared with predictions of the statistical thermodynamic theory. For the absolute value of the interfacial thickness values of 3 nm and 2 nm are calculated for nonhydrogenated and partially hydrogenated blockcopolymers.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 264 (1986), S. 323-331 
    ISSN: 1435-1536
    Keywords: Block copolymers ; stress induced crystallization ; relaxation behaviour ; crystallization kinetics
    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 Thermoplastic elastomers show considerable flow if they are subjected to large strains. To investigate the influence of stress induced crystallization, elastomers showing stress induced crystallization are synthesized by hydrogenation of poly(butadienes) and poly(styrene-b-butadiene-b-styrene) block polymers. The influence of the methylene sequence length on the crystallization behaviour is evaluated. From stress relaxation experiments, the crystallization kinetic is analyzed. Heterogeneous nucleation and fibrillar crystal growth is detected for all block polymer systems. The kinetic behaviour is described by a preorientation of elastomer chains near the domain surface.
    Type of Medium: Electronic Resource
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