Synthesis and characterization of polyvinyl alcohol/cationic polyurethane binder blend as solid polymer electrolyte

In the present study, we have fabricated the blends of polyvinyl alcohol (PVA) and cross linked chain extended cationic polyurethane binder (PUB). X-ray diffraction (XRD) reveals that the crystallinity decreases with PUB loading. The hydrogen bonding of PVA and PUB are confirmed by shifting of C=O (1750–1700 cm−1) and N-H resign (1400–1380 cm−1) of Fourier transform infrared spectroscopy (FTIR) spectra. The optical properties of the blend system such as direct and indirect band gap were evaluated by UV absorption spectra. The band gap decreases with the loading of PUB. The miscibility of PUB and PVA blend has been confirmed by differential scanning calorimetry (DSC). It shows a decrease in glass transition (Tg) and decomposition temperature (Td), and increase in melting temperature (Tm) with PUB loading. The plane morphology of blend was confirmed by scanning electron microscopy (SEM) with better homogeneity (for 50 % PUB loading). The frequency-dependent AC conductivity seems to follow Jonscher power law in which power factor (s) varies in the range 0.74 < s < 0.89. The DC electrical conductivity was calculated from Cole-Cole plot across broadband frequency (50 Hz–10 MHz) and high temperature range (40–120 °C). The temperature-dependent DC conductivity of PVA/PUB blends obey Vogel-Tamman-Fulcher (VTF) equation which demonstrates the electrical conduction in polymer blends was thermally activated.