Blends of hexanoyl chitosan/epoxidized natural rubber doped with EMImTFSI

Hexanoyl chitosan soluble in THF is prepared by acyl modification of chitosan. Epoxidation natural rubber (ENR25) (25 mol%) is chosen to blend with hexanoyl chitosan. Films of hexanoyl chitosan/ENR25 blends containing lithium bis(trifluoromethanesulfonyl)imide (LiN(CF₃SO₂)₂) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMImTFSI) are prepared by solution casting technique. FTIR results suggested that LiN(CF₃SO₂)₂ salt interacted with hexanoyl chitosan, ENR25, and EMImTFSI. EMImTFSI interacted with hexanoyl chitosan and ENR25 to form EMIm⁺-hexanoyl chitosan and EMIm⁺-ENR25 complexes, respectively. The effect of EMImTFSI on the morphology and thermal properties of the blends is investigated by polarized optical microscopy (POM) and differential scanning calorimetry (DSC), respectively. The ionic conductivity of the electrolytes is measured by electrochemical impedance spectroscopy (EIS). Upon addition of 12 wt% EMImTFSI, a maximum conductivity of 1.3 × 10^?6 S cm^?1 is achieved. Methods based on impedance spectroscopy and FTIR are employed to study the transport properties of the prepared polymer electrolytes. The ac conductivity was found to obey universal law, σ(ω)?=?σ _dc ?+?Aω ^S . The temperature dependence of exponent s is interpreted by the small polaron hopping (SPH) model.