Study on Mechanical Behaviors and Electrolyte Uptake of PVDF/PES/TiO₂ Composite Fiber Separators

Abstract In this paper, polyvinylidene fluoride (PVDF)/polyether sulfone (PES) spinning solution with different TiO2 content was obtained by in-situ generation. The prepared spinning liquid was fabricated into PVDF/PES/TiO2 composite membranes via electrospinning. The scanning electron microscopy (SEM), differential scanning calorimetry (DSC), mechanical properties, electrolyte uptake were conducted to test the performance of the obtained separators. The effect of TiO2 contents on the properties of PVDF/PES separators was discussed. The experimental results show that the doping of nano-TiO2 particles will enhance the performance of the separators. DSC test and electrolyte uptakes showed that the enthalpy of the polymer decreased and the electrolyte uptake increased with TiO2 contents. When the separators contents 2 wt% TiO2, the enthalpy changes reach the maximum (28.259 J/g), and the crystallinity is measured to 26.99%. With the TiO2 addition increases, the tensile strength of the membrane also showed the tendency of increasing first and then decreasing. At 6 wt%TiO2, the tensile strength of the membrane was better, reaching 5.606 N/mm2, and the toughness was the best. It shows that the addition of TiO2 helps to enhance its tensile strength as well as toughness When the TiO2 content is 6 wt%, the overall performance of the membrane is the best.