Structural, thermal, dielectric and modulus studies on magnesium-doped tamarind seed polysaccharide based biopolymer electrolytes

Abstract

We report the X-ray diffraction (XRD) profile, differen-tial scanning calorimetry (DSC) plots and measure-ments of ionic conductivity, dielectric parameters and electric modulus parameters for different compositions of magnesium chloride (MgCl2)-doped tamarind seed polysaccharide (TSP) biopolymer electrolyte films. Dif-ferent compositions of the biopolymer and dopant salt were used in the ratios of TSP: MgCl2 (90: 10, 80: 20, 70: 30 and 60: 40 wt.%). The XRD and DSC plots confirmed the highest amorphous nature for the opti-mum composition TSP: MgCl2 (70: 30 wt.%). AC impedance spectroscopy was used to determine the ionic conductivities of the prepared films. For TSP: MgCl2 (70: 30 wt.%), a maximum conductivity of 1.27 × 10-5 S cm–1 was reported at 303 K and 2.09 × 10–5 S cm––1 at 363 K. The values of the dielectric constant and die-lectric loss were higher at lower frequencies and grad-ually declined with the frequency for all the films. The highest values of the dielectric constant and dielectric loss for the composition TSP: MgCl2 (70: 30 wt.%) were reported to be 3.87 × 104 and 2.08 × 105 respec-tively. Studies of the electric modulus spectra revealed the relaxation process that occurs in biopolymer elec-trolyte systems.