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  • 1
    Electronic Resource
    Electronic Resource
    Self-assembly of the electroactive complexes of polyaniline and surfactant (1995)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 196 (1995), S. 2443-2462 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: An electroactive material with remarkable solubility, processibility as well as mechanical properties has been developed by complexation (thermal doping) of polyaniline (PANi) emeraldine base with dodecylbenzenesulfonic acid (DBSA) in the solid state. Isothermal treatment of such a mixture was found to promote the complex formation. Optimum conditions of complexation were established with respect to the formation of layered structure, electrical conductivity and solubility. The optimal temperature for the doping process was found to be in a range of 100-120°C while the best ratio of DBSA to PANi was between 3:1 and 4:1 by weight, a nearly stoichiometric equivalence of aniline repeat units and DBSA molecules. The time of isothermal treatment should be controlled within 30 min. Thermal doping induced orientation to polymer chains in a layered structure, whereby the hydrophobic tails of the surfactants function as spacers between parallel stacks of the main chains. This anisotropy was achieved by the self-assembly during the thermal doping rather than ordinary drawing or stretching of the polymers. A unique liquid crystalline mesophase with a smectic-like optical texture was observed for the soluble portions of some specimens. The excess DBSA in the samples is considered to function as a solvent and to give rise to the liquid crystalline fluidity of the phase. The scanning tunneling microscopy (STM) image 5000 × 5000 Å on a submicrometer scale obtained from a PANi/DBSA thin film exhibits a surface morphology with a granular size of 200-300 Å. The image of 150 × 150 Å on a molecular scale obtained from multilayer PANi/DBSA deposited on a highly oriented pyrolytic graphite (HOPG) surface provides a direct observation of a self-assembled structure and close layer packing of the polymer backbone with dimensions in accord with the results found by X-ray diffraction. Our results indicate that the thermal doping process of polyaniline by DBSA offers new possibilities to obtain optimal structures through a self-assembly.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1995.021960803
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis of new smectic C* liquid-crystalline block copolymers (1996)
    Weinheim : Wiley-Blackwell
    Macromolecular Rapid Communications 17 (1996), S. 813-824 
    Details
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A series of smectic C* liquid-crystalline (LC) block copolymers were successfully synthesized via the living anionic polymerization of polystyrene with optically active methacrylate monomers containing (S)-2-methylbutyl 4-(4-hydroxyphenylcarbonyloxy)-biphenyl-4′-carboxylate mesogens. These materials are the first reported smectic C* block copolymers. Anionic polymerization in tetrahydrofuran (THF) at -70°C leads to LC block molecular weights of approximately twenty repeating units. The number-average molecular weight of the polystyrene block was varied from 7000 to 20000 to adjust the composition in the block copolymers. Differential scanning calorimetry and optical microscopy indicate that the smectic C* phase is present in the systems over broad temperature ranges.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/marc.1996.030171109
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  • 3
    Electronic Resource
    Electronic Resource
    Studies on the transesterification of polycarbonate/poly(ethylene terephthalate) blends. I: Mechanisms and extent of reaction (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 34 (1994), S. 301-306 
    Details
    ISSN: 0959-8103
    Keywords: polycarbonate/poly(ethylene terephthalate) blends ; transesterification ; reaction mechanism ; reaction extent ; 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: Transesterification of polycarbonate/poly(ethylene-terephthalate) (PC/PET) blends and the reaction extent were investigated by DSC, FTIR, 1H NMR and Soxhlet extraction. A new characteristic peak appeared in the FTIR spectrum of PC/PET blends after heat treatment, which indicates that new copolymers were formed in the transesterification of the PC/PET blends. The reaction extent was characterized by the absorbance ratios of the FTIR characteristic bands. The reaction extent was associated not only with the reaction conditions but also with the composition of the blends. These results were confirmed by chemical analysis of the extracted products in CH2Cl2 solvent and FTIR analysis. For all the blends studied, the blend with 50/50 wt% had the highest reaction extent. The reaction mechanisms and extent were also confirmed by 1H NMR analysis.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1994.210340309
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  • 4
    Electronic Resource
    Electronic Resource
    Studies on the transesterification of polycarbonate/poly(ethylene terephthalate) blends. II: Effect of transesterification on the compatibility and crystallization behaviour of the blends (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Polymer International 34 (1994), S. 307-311 
    Details
    ISSN: 0959-8103
    Keywords: PC/PET blends ; transesterification ; compatibility ; crystallization behaviour ; melting behaviour ; 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: The effect of transesterification on the compatibility of polycarbonate poly(ethylene terephthalate) (PC/PET) blends and the crystallization and melting behaviour of PET was studied. The results show that with increase of the reaction extent, the compatibility of the blends was enhanced during melt-processing, from completely incompatible to partially compatible, then to complete compatibility. In addition, with the increase of reaction extent, the crystallization ability and crystallinity of PET decreased. A new endotherm peak was discerned in DSC thermograms and its position and peak area were closely related to the reaction conditions, which was explained by the changes in the crystalline regions in the PC/PET blends. The effect of transesterification on the multiple melting behaviour of PET in PC/PET blends is also discussed.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pi.1994.210340310
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  • 5
    Electronic Resource
    Electronic Resource
    Preparation of polymer-protected Pt/Co bimetallic colloid and its catalytic properties in selective hydrogenation of cinnamaldehyde to cinnamyl alcohol (1996)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 7 (1996), S. 719-722 
    Details
    ISSN: 1042-7147
    Keywords: Pt/Co bimetallic colloid ; selective hydrogenation ; cinnamaldehyde ; 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
    Notes: A polymer-protected Pt/Co bimetallic colloid with a molar ratio of 3:1 has been prepared by a polyol process. Over the above Pt/Co bimetallic colloid catalyst, cinnamaldehyde can be selectively hydrogenated to cinnamyl alcohol with 99.8% selectivity at 96.2% conversion.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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