The Effect of Carboxymethyl Cellulose as Bio Filler on Ionic Conductivity and Physical Property of Waste Cooking Oil Based Polyurethane Composite Polymer Electrolyte

Abstract

Waste cooking oil (WCO) is an under-utilized, highly abundant raw material from food industry. In this study, WCO was used to prepare solid polymer electrolyte (SPE) films via solvent-free method. WCO was first pretreated and converted into polyol using epoxidation and hydroxylation reaction. Then, WCO-based polyol was combined with diisocyanate, LiCF3SO3 and carboxymethyl cellulose (CMC) to obtain polyurethane SPE films. CMC was added to SPE as bio-filler to observe the effect on ionic conductivity and mechanical properties of SPE. SPE films were characterized using Fourier transformed infrared spectroscopy, electrochemical impedance spectroscopy, x-ray diffraction spectrometer (XRD), differential scanning calorimetry and tensile strength. Addition of CMC resulted in increase of ionic conductivity up to 1.19 x 10-5 S/cm for 15% CMC. The ionic conductivity supported with reduced crystalline peaks intensity in XRD to show that the amorphous nature of SPE increased as more CMC added. Tensile strength also increased with addition of CMC and peaked at 10% CMC (34.17 MPa) due to effective hydrogen bond interaction between CMC and PU or salt. However, increased CMC amount further to 15% reduced tensile strength due to agglomeration of CMC particles. As a conclusion, addition of CMC is a viable method to improve both ionic conductivity and mechanical property of SPE.

Polyurethane‐based polymer electrolyte for lithium ion batteries: a review

“…The addition of 15% CMC resulted in an increase in ionic conductivity of 1.19 × 10 −5 S cm −1 . The ionic conductivity was accompanied by a decrease in the strength of crystalline peaks in XRD, indicating that the amorphous nature of the SPE increased when more CMC was added 116 . Additionally, the composite WPU/cellulose nanocrystal (CNC) exhibited a lower T g value compared to the non‐composite WPU due to interactions between WPU and CNC that are thought to prevent soft segment chains from forming crystalline domains, allowing them to move more freely and thus increasing the ionic conductivity value 117 .…”

“…114,115 Carboxymethylcellulose (CMC) was used as a bio-filler for waste cooking oil (WCO) based PU electrolyte. 116 To make PU SPE films, a WCO-based polyol was mixed with diisocyanate, LiCF 3 SO 3 and CMC. The addition of 15% CMC resulted in an increase in ionic conductivity of 1.19 × 10 −5 S cm −1 .…”

“…The ionic conductivity was accompanied by a decrease in the strength of crystalline peaks in XRD, indicating that the amorphous nature of the SPE increased when more CMC was added. 116 Additionally, the composite WPU/cellulose nanocrystal (CNC) exhibited a lower T g value compared to the non-composite WPU due to interactions between WPU and CNC that are thought to prevent soft segment chains from forming crystalline domains, allowing them to move more freely and thus increasing the ionic conductivity value. 117 On the other hand, Cao and co-workers 118 proved that, on increasing the CNC filler content from 0 to 30 wt%, the Young's modulus and tensile strength of WPU/flax CNC increased significantly from 0.51 to 344 MPa and 4.27 to 14.86 MPa, respectively.…”

“…As a result, the reduced crystallinity and T g boost ionic conductivity and rate capability 114,115 . Carboxymethylcellulose (CMC) was used as a bio‐filler for waste cooking oil (WCO) based PU electrolyte 116 . To make PU SPE films, a WCO‐based polyol was mixed with diisocyanate, LiCF 3 SO 3 and CMC.…”