Composite Electrolytes Comprising Polytetramethylene/Polypropylene Glycol-Based Waterborne Polyurethanes and Polyethylene Oxide via a Mixture Design Approach
By Wen, Ten-Chin; Tseng, Hwang-Shin & Cheng, Tsung-Tien
Published in Industrial & Engineering Chemistry Research
2000
Abstract
The composite electrolytes (CEs) were prepared by impregnating the ternary composites comprising polypropylene glycol-based waterborne polyurethane (denoted as WPU(PPG)), polytetramethylene glycol-based waterborne polyurethane (denote as WPU(PTMG), and polyethylene oxide (PEO) with LiClO4/PC. The data of the swollen weight (Sw) and the room-temperature conductivity (σ25) for CEs were fitted as empirical regression equations by using mixture design. These empirical equations were used to construct contour plots, facilitating comparisons of synergistic/antagonistic effects among the mixed polymers. The contour plots show that the maximum Sw (64.3%) appears at point X3 (PEO 95% and WPU(PPG) 5%), while the maximum σ25 (≈10-3 S/cm) appears in a wide region (WPU(PPG) = 5-43%, WPU(PTMG) < 37%, and PEO > 27%). Differential scanning calorimetry (DSC) results showed immiscibility between WPU(PTMG) and PEO and partial immiscibility between WPU(PPG) and WPU(PTMG)/PEO. A polarized micrograph (PM) of the composites was also examined for PEO spherulites. The contour plot results of Sw and σ25 can be explained by the interactions among polymers on the basis of their molecular structures, also evidenced by both DSC and PM results.