Novel crosslinked gum tragacanth electrolyte with enhanced thermal, mechanical and water resistive properties

Abstract

Although electrolytes prepared from natural substances have taken up research towards a greener future, practical difficulties in their mechanical and water resistive properties are yet to be addressed by many. In this current paper, a natural gum tragacanth is graft copolymerized with tertiary butyl acrylate utilising glutaraldehyde as the crosslinker and ascorbic acid and potassium persulfate as the initiators. From the TGA analysis, enhanced thermal stability is observed in the crosslinked membrane. The DSC analysis reveals that the crosslinked gum exhibits a glass transition temperature (Tg) of 66 °C and a melting temperature (Tm) of 86 °C. The water uptake of the crosslinked membrane was found to be lower than the pure non-crosslinked membrane. The stress-strain curves of the crosslinked electrolyte showed a tensile strength of 3.58Mpa and a percent elongation of 302%. The effect of the crosslinker glutaraldehyde and the ionic salt lithium nitrate is studied with the help of XRD and FTIR. The electrolyte is characterised to be a good ionic conductive membrane as its conductivity value is found to be 4.72 ×10−4 Scm−1 through EIS measurements. The Arrhenius behaviour of temperature-dependent conductivity was studied and the activation energy values for all the films were calculated.

Keywords

• Gum tragacanth
• Graft copolymerisation
• Crosslinking
• Solid polymer electrolyte
• Impedance analysis