Casting of Poly Hydroxybutarate/Poly (vinyl alcohol)Membranes for Proton Exchange Fuel Cells

Gamma irradiation was used efficiently for casting poly hydroxybutarate(PHB) and phosphorylated poly (vinyl alcohol)(PVA) with different ratios. The optimum gamma irradiation dose for attaining finally crosslinking was 10 kGy. It was found that adding 0.5% phosphate-terminated silica nanoparticles (SiO2-P NPs) in the cast mixture was enough for membranes reinforcement. Membranes characterizations are carried out using FT-IR and tensile strength for examining their chemical and physical properties. Morphological properties of the casted membranes were studied using scanning electron microscope while their crystallinity was investigated using x-ray diffraction. Thermal characterization was performed using thermal gravimetric analysis. Water uptake and ion exchange capacity are determined as well. The prepared membranes' highest proton conductivity value was 8.6 × 10−2 S/cm while their free volume sizes were measured using positron annihilation lifetime technique (PALS). The casted membranes are strongly recommended to be used into the proton exchange membrane fuel cell (PEMFC) from performance and durability point of view.