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The investigation of poly(propylene glycol) (PPG)-based waterbornepolyurethane (WPU(PPG)) consisting of PPG, dimethylolpropionic acid (DMPA)and isophorone diisocyanate (IPDI) as solid polymer electrolyte has beendone in this thesis. The swelling behavior of WPU(PPG) impregnated with 1 M lithiumperchlorate (LiClO4) in propylene carbonate (PC) solution was first studied,because the extent of liquid electrolyte is considered to be responsible forthe ionic conductivity of polymer electrolytes. Afterwards, conductivitiesof the corresponding WPU(PPG) electrolytes were obtained by using alternatingcircuit (AC) impedance. A good conductivity of 10-2~10-3 S/cm can be achievedfor WPU(PPG) electrolyte containing 84% LiClO4/PC, which possesses a poormechanical strength. On the other hand, the composite electrolyte (CE),by means of mixing WPU(PPG), PEO and LiClO4/PC, which contains littleLiClO4/PC, possessing both a high conductivity of ca. 10-3 S/cm and a goodmechanical strength. Furthermore, in order to clarify the interaction between WPU(PPG) andLiClO4 for its further application, fourier-transform infrared spectroscopy( FTIR), X-ray photoelectron spectroscopy (XPS), differential scanningcalorimetry (DSC), and electrochemical impedance spectroscopy (EIS) wereutilized to monitor the phase change of this WPU with the doped LiClO4concentration. Significant changes occur in the FTIR spectrum of the WPUwith the added salt concentration above 1 mmol/g WPU, indicating that aninteraction with the lithium cation within the hard segment and between thehard and soft phases occurs. The soft segment Tg increases with increasingLiClO4 through the examination of DSC. XPS results reveal that the componentof nitrogen polaron sites (N+) increases with increasing LiClO4, and that thesaturation level of salt doping is evidenced by the mole ratio of componentC-O to C=O; meanwhile, a rearrangement in long chain of the soft domain hasalso been observed when this WPU is doped with LiClO4. EIS results indicatean increase in bulk conductivity as the salt concentration is increased. Thepresent study concluded that the characteristic phase separation of the WPUis altered as a result of the interaction of lithium cations within the polarhard domains, and that the phase intermixing is promoted by the coupling ofthe hard and soft phases.
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