The effect of isocyanate structure on ionic conductivity of waste cooking oil based polyurethane solid polymer electrolyte

摘要

Polyurethane solid polymer electrolyte (SPE) films was prepared via solvent-free method using waste cooking oil-based polyol, diisocyanate, LiTFSI salt and ethylene carbonate as plasticizer. Two types of diisocyanate were chosen; aromatic 4,4-diphenylmethane diisocyanate (MDI) and aliphatic 1,6-hexamethylene diisocyanate (HDI) and the effect of diisocyanate structure on SPE properties were characterized using Fourier Transform Infrared Spectroscopy (FTIR), Electrochemical Impedance Spectroscopy (EIS), Differential Scanning Calorimetry (DSC) and X-Ray Diffractometry (XRD). The highest ionic conductivity achieved was 5.76 × 10~(-6) S cm~(-1) using MDI. This was supported with lower crystallinity observed by decrease in peaks intensity in XRD. The findings indicated that aromatic diisocyanate is more suitable to produce polyurethane SPE.