Study of solid polymer electrolyte based on biodegradable polymer polycaprolactone

Abstract

In this research, the polymer electrolyte material based on poly caprolactone (PCL) has been synthesized and characterized. Polycaprolactone is non-toxic and biodegradable polymer that is environmentally friendly. The preparation of the polymer electrolyte film was carried out by a casting method whereby the PCL polymer was dissolved in a tetrahydrofuran (THF) solvent. Lithium perchlorate salt (LiClO4) as a source of lithium ions was added to solution with a composition (5-40) % by weight. The solution was slowly evaporated in vacuum oven until the film was formed. The ionic conductivities, crystal structures, morphologies and thermal properties of polymer electrolytes were characterized by impedance spectroscopy, x-ray diffraction (XRD) and Fourier Transformation Infrared Spectrometer (FTIR), Scanning Electron Microscope (SEM) and Differential Scanning Calorimeter (DSC), respectively. The results of the conductivity measurements showed that the PCL conductivity increased from 3.45 x 10-11 Scm-1 to 5.52 x 10-6 Scm-1 with a 30% weight salt content of LiClO4. Observations with XRD showed a more amorphous polymer with more salt addition and FTIR results showed that there was interaction between active groups on polymers with salt. The thermal properties showed that the melting points of polymer became lower with more salt addition.