Development and characterization of poly(oxy-1,4-phenylenesulfonyl-1,4-phenylene) for proton exchange membranes

Proton Exchange Membranes (PEMs) were synthesized from Poly (oxy-1,4-phenylenesulfonyl-1,4-phenylene) (PES), sulfonated for 1 and 2h, and modified with 0, 5, and 10 wt% nanoclays. The membranes were characterized by evaluating their physicochemical properties, such as ion exchange capacity, oxidative stability, porosity and water uptake. PEMs were modified with the sulfonation time and nanoclays addition to favor the mechanical properties and proton conductivity, which were evaluated. The sulfonation time and the concentration of nanoclays directly favored properties such as contact angle, water absorption, porosity, and mechanical properties. However, a higher concentration of nanoclays (e.g., 10 wt%) damaged the mechanical properties of PES membranes specifically. The membrane with 5 wt% of nanoclay and a sulfonation time of 2h achieved the best performance.