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  • Polymer and Materials Science  (3)
  • isomorphous substitution  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of thermal analysis and calorimetry 54 (1998), S. 901-911 
    ISSN: 1572-8943
    Keywords: cobalt ; isomorphous substitution ; manganese ; tetraalkylammonium cations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Pure silica zeolite ZSM-5 has been synthesised in a slightly acidic aqueous fluoride medium which produces the protonated form of the zeolite ZSM-5 [1]. Tetrahalometallate [2] species of cobalt and manganese have been synthesised and increasing mole fractions incorporated into the zeolite synthesis gel. The products have been analysed and characterised using simultaneous thermogravimetric-derivative thermogravimetric analysis (TG-DTG). The thermal decomposition, under nitrogen of the associated tetraethylammonium (TEA+) and tetrapropylammonium (TPA+) cations occluded within the zeolite channels is indicative and characteristic of the incorporation of the heteroatoms into the zeolitic framework. Analysis by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray fluorescence (XRF), and Fourier transform infrared spectroscopy (FTIR) has confirmed the reliability of thermogravimetric (TG) and derived thermogravimetric analysis (DTG) as a diagnostic tool.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of thermal analysis and calorimetry 63 (2000), S. 329-338 
    ISSN: 1572-8943
    Keywords: copper ; fluoride ; isomorphous substitution ; nickel ; ZSM
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The synthesis of pure silica ZSM-5 has been modified to produce highly crystalline material in the protonated form, necessary for catalytic activity, directly from a low water fluoride gel. Tetrahedrally co-ordinated divalent species of nickel and copper have been synthesised as salts of large organic cations and increasing mole fractions incorporated into the zeolite gels. The products have been analysed and characterised using simultaneous thermogravimetric and derivative thermogravimetric analysis (TG-DTG). The thermal decomposition under nitrogen of the metal associated cations, tetraethylammonium (TEA+), occluded within the zeolite channels is indicative and characteristic of the incorporation of heteroatoms into the zeolite framework. Anomalous losses in the systems can be explained by Jahn–Teller distortions. The mass losses increased with increased metal loading and were consistent with those reported in full water system, analysis also confirmed that the material was hydrophobic and thermally stable. Analysis by X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray fluorescence (XRF), Fourier transform infrared spectroscopy (FTIR) and Atomic Absorption Spectroscopy (AAS) has confirmed the reliability of TG-DTG as a diagnostic tool. The maximum levels of substitution achieved were (mass%) Ni 3.93 and Cu 4.38.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 5 (1994), S. 79-89 
    ISSN: 1042-7147
    Keywords: Copolymers bropylene-7 methyl 1-6 octadiene ; Sulfonation ; Ionomers aggregation state ; Mechanical properties ; 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: Polypropylene ionomers have been prepared by sulfonation of copolymers of propene and 7 methyl, 1-6 octadiene, followed by neutralization to cesium salts. Both WAXS and SAXS were used to study the morphology of the samples, while their thermal properties were studied by DSC and their mechanical properties by DMTA. The sulfonation process is shown to cause a further drop in crystallinity in addition to the effect of comonomer incorporation. Ion clustering is observed when the extent of sulfonation is high enough, the limit being dependent on the copolymer composition. The ion pairs which are not incorporated into the cluster cause a small-angle upturn in the WAXS pattern. The mechanical properties are strongly affected by the drop in crystallinity, but may be partly recovered due to ion clustering. No disruption of the ion clusters is observed before thermal decomposition of the polymer.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 28 (1990), S. 1979-1986 
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Block copolymers consisting of long styrene midblocks and much shorter 4-vinyl pyridine end-blocks were quaternized with n-iodo alkanes (2 ≤ n ≤ 10) to give block ionomers of a novel architecture. The name “bottlebrush” seems appropriate for these materials. A preliminary investigation of the morphology of these systems, prepared by in situ quaternization, is reported here. The morphology is dependent on both the length of the iodo alkane and the relative sizes of the blocks. Even with identical sample histories, two distinct morphologies are seen. One of these is characterized by a single broad SAXS peak, while the other shows a much narrower peak and higher-order features. The latter morphology is associated with the higher ionic to nonionic ratios and long side chains.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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