Incorporation of poly(vinylidene fluoride) in sulfonated poly(ether ether ketone) matrix for membrane mechanical stiffness

Abstract

Development of promising polymer based material for the membrane of the fuel cell was crucial to improve its performance and lifetime. The sulfonated polymer physicochemical properties depend on the degree of sulfonation (DS). High DS of sPEEK exhibits high performance, but poor in mechanical properties due to high water absorption. So, this present study aimed to investigate the effect of incorporating polyvinylidene fluoride (PVDF) at different content toward improvement of high DS sPEEK mechanical properties and ion conduction. The blending approach was used to mix the sPEEK with PVDF (content: 5 wt%; 10 wt%; 15 wt% and 20 wt%). The blended sPEEK/PVDF membrane were prepared by casting and drying the solution using the phase inversion technique. The result showed that the incorporation of PVDF in sPEEK matrix had improved the mechanical properties by reducing water uptake, swelling degree, and dimensional change. Other than that, the tensile strength of blended membranes also higher than neat sPEEK. The proton conductivity of sPEEK/PVDF 15 (7.23 mS/cm) was quite higher and comparable with neat sPEEK (10.31 mS/cm) and Nafion membrane (12 mS/cm). In summary, the incorporation of PVDF in high DS of sPEEK had improved the mechanical properties with promising ionic conduction.