Synthesis of waste cooking oil based polyurethane solid polymer electrolyte: the effect of metal salts / Marina Abu Husin

Polyurethane (PU) based on polyol, derived from waste cooking oil has been synthesized and characterized for potential use as a base material for electrolytes. One-pot epoxidation and hydroxylation process of waste cooking oil formed a polyol with %FFA value of 10.4%, acid value of 20.7 mg KOH/g and iodine value of 45.72 I2/ 100g. Polyols, metal salts, plasticizer and solvent together with 2, 4' -diphenylmethane diisocyanate were used to synthesize the polyurethane solid polymer electrolyte via solution casting technique. Three types of metal salts used are lithium chloride (LiCI), lithium perchlorate (LiCIO4) and sodium chloride (NaCl). Ethylene carbonate (EC) plasticizer was used to enhance the ionic conductivity of the polymer electrolytes. The formation of urethane linkages and the chemical interaction between segmented PU and cation/anion from metal salts were confirmed by Fourier transform infrared (FTIR) analysis. Thermal studies carried out by Thermogravimetric analysis (TGA) and Differential scanning calorimetry (DSC) has proven the occurrence of polymer-salt complexation as well as gave information about the polymer chain dynamics and plays a vital role in ionic conduction. The highest ionic conductivity value is 3.02x10-5 S/cm recorded by PU-LiCl electrolyte. These observations indicated the synthesized PU possessed favorable properties to act as a base material in polymer electrolytes.