Spectroscopic Investigations of Poly(oxypropylene)glycol-Based Waterborne Polyurethane Doped with Lithium Perchlorate

Polyaddition of isophorone diisocyanate to poly(oxypropylene)glycol (PPG)-Based waterborne polyurethane (WPU) synthesized by a modified acetone process was performed. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), and impedance spectroscopy (IS) were utilized to monitor the phase change of this WPU with the doped lithium perchlorate (LiClO 4 ) concentration. Significant changes occur in the FTIR spectrum of the WPU with the added salt concentration above 1 mmol/g WPU, indicating that an interaction with the lithium cation within the hard segment and between the hard and soft phases occurs. The soft segment T g increases with increasing LiClO 4 through the examination of DSC. XPS results reveal that the component of nitrogen polaron sites (N + ) increases with increasing LiClO 4 and that the saturation level of salt doping is evidenced by the mole ratio of component C−O to C O; meanwhile, a rearrangement in the long chain of the soft domain has also been observed when this WPU is doped with LiClO 4 . IS results indicate an increase in bulk conductivity as the salt concentration is increased.