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  • 1
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 30 (1992), S. 2025-2031 
    ISSN: 0887-624X
    Keywords: poly(propylene glycol) ; poly(methyl methacrylate) ; LiCF3SO3 ; compatibility ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Stable to atmospheric moisture, adhesive and transparent polymer electrolytes have been prepared by blending poly(methyl methacrylate) (PMMA) with poly(propylene glycol)-425/LiCF3SO3 complexes. The blending of the polymers has been achieved by a method developed in our laboratory: free radical polymerization of methylmethacrylate in the polyether/salt matrix. A series of polymer blend complexes varying in PMMA content (up to 20% by weight) and oxygen/metal ratios (25, 16, and 8) have been synthesized and their properties studied. All the samples prepared in this study were found to be optically clear unlike the higher molecular weight poly(propylene glycol)-2000 (PPG-2000) system which required a minimum salt concentration to compatibilize a specific amount of PMMA with PPG. The mechanisms by which the salt holds the otherwise incompatible polymers together in a single phase have been investigated by FT-IR. Our studies show a weak coupling of the ether oxygens in the PPG with the ester groups of the PMMA through the lithium cations. Discrete changes has been observed in the FT-IR spectrum of PMMA when doped with the lithium salt hitherto unnoticed with other dopants. Gel permeation chromatography results of the PMMA samples isolated from the solid electrolytes indicate the molecular weight to vary between 43000 and 121000 with relatively narrow distributions, 1.6-2.0. The ionic conductivities of the polymer blend electrolytes were fairly high (10-5 S/cm) at room temperature. The PMMA neither significantly influenced the Tg of the blend complexes nor effected the ionic conductivities drastically. The ionic conductivity as a function of temperature followed the empirical Vogel-Tammann-Fulcher equation. The blending of PMMA with PPG/LiCF3SO3 complexes was found to impart good adhesiveness to the solid electrolytes while making them stable to atmospheric moisture. © 1992 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 2
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 32 (1994), S. 2221-2233 
    ISSN: 0887-6266
    Keywords: poly(ethylene glycol) ; ethylene oxide-propylene oxide copolymer ; blends ; poly(methyl methacrylate) ; LiCF3SO3 ; ionic conductivity ; effective medium theory ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Highly conductive solid polymeric electrolytes based upon low molecular weight poly(ethylene glycol) and ethylene oxide/propylene oxide copolymers blended with up to 50% by volume of poly(methyl methacrylate) have been synthesized using LiCF3SO3 (25:1 ether oxygen to cation ratio). Room-temperature ionic conductivities were measured to be in the range 10-4 to 10-5 S/cm for poly(methyl methacrylate) concentrations up to 30% by volume. In some cases, the addition of the poly(methyl methacrylate) enhanced the conductivity. All of the electrolytes studied were either amorphous or crystallized below 0°C. The variation of conductivity with temperature and polymer composition was measured and the results were analyzed in terms of effective medium theory and semiempirical considerations. Ionic transport is coupled to the structural relaxation of the polymer segments. At lower temperatures activated processes were required. Both charge carrier mobility and charge concentration were found to contribute to conduction. The effective medium theory quantitatively describes conductivities of amorphous heterogenous systems of limited miscibility (microphase separation) quite well. For miscible or partially crystalline systems other effects not incorporated in this theory play an important role, and conductivities are measured to be higher than theoretically predicted. © 1994 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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