Spectroscopic and thermal analyses for the effect of acetic acid on the plasticized sodium carboxymethyl cellulose

Abstract

© 2020 Elsevier B.V. Solid polymer electrolytes (SPEs) based on sodium carboxymethyl cellulose (CMC) mixed with different percentages of acetic acid and constant percentage of glycerol (Gly) as a plasticizer, to enhance electrical properties, are prepared using casting technique. Then, the prepared SPE films are characterized using Ultraviolet-Visible spectroscopy (UV–Vis.), Fourier Transform Infrared spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR), Scanning electron microscope (SEM) and Electrical Impedance Spectroscopy (EIS). Also, thermal properties of the studied SPEs are studied using Thermo Gravimetric Analyzer (TGA) and its derivative (DTA). The obtained results of UV–Vis. study indicated that the prepared samples possesses three optical band gaps and that the optical band gaps decreased due to increasing acetic acid concentration up to 5 wt.%. FTIR results predict the presence of new absorption band around 1693 cm-1. Acetic acid/CMC interaction is further described by 1HNMR indicating chemical shift in carbonyl carbon (C = O) in some samples and disappearing of it in another samples. Meanwhile, EIS results indicated that the highest ionic conductivity obtained equals 7.64E-06 S/cm at room temperature for sample A3. Finally, TGA curves showed that the thermal stability is changed with changing acid concentration and three stages of weight loss are observed. The obtained results indicated that CMC-Gly-acetic acid SPEs is a perfect choice to be used as a solid polymer electrolyte since the electrical properties of CMC are improved.