Composite electrolytes comprising polytetramethylene/polypropylene glycol-based waterborne polyurethanes and polyethylene oxide via a mixture design approach

The composite electrolytes (CEs) were prepared by impregnating the ternary composites comprising polypropylene glycol-based waterborne polyurethane (d enoted as WPU(PPG)), polytetramethylene glycol-based waterborne polyurethan e (denote as WPW(PTMG), and polyethylene oxide (PEO) with LiClO4/PC. The da ta of the swollen weight (S-w) and the room-temperature conductivity tots) for CEs were fitted as empirical regression equations by using mixture desi gn. These empirical equations were used to construct contour plots, facilit ating comparisons of synergistic/antagonistic effects among the mixed polym ers. The contour plots show that the maximum S-w (64.3%) appears at point X -3 (PEO 95% and WPU(PPG) 5%), while the maximum sigma(25) (approximate to 1 0(-3) S/cm) appears in a wide region (WPU(PPG) = 5-43%, WPU(PTMG) ( 37%, an d PEO > 27%). Differential scanning calorimetry (DSC) results showed immisc ibility between WPU(PTMG) and PEO and partial immiscibility between WPU(PPG ) and WPU(PTMG)/ PEG. A polarized micrograph (PM) of the composites was als o examined for PEO spherulites. The contour plot results of S-w and sigma(2 5) can be explained by the interactions among polymers on the basis of thei r molecular structures, also evidenced by both DSC and PM results.