부산대학교 도서관

In this study, chloromethylated polysulfones (CPS) were used as precursors to synthesize two kinds of sulfonated polysulfones with flexible side chains, namely PS-BS (The end of the side chain contains a sulfonic acid group) and PS-BDS (The end of the side chain contains two sulfonic acid groups). This was achieved through nucleophilic substitution reaction using sodium 4-hydroxybenzenesulfonate and disodium 1,2-dihydroxybenzene-3,5-disufonate as nucleophilic reagents, respectively. The chemical structures of the resulting sulfonated polysulfones were characterized using the Fourier infrared spectrum (FT-IR) and nuclear magnetic hydrogen spectrum ( H1-NMR). The proton exchange membranes (PEMs) were fabricated using a solution casting method. Thermogravimetric analysis (TGA) analysis revealed that the obtained PEMs exhibited stability up to 270 °C. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis indicated that PS-BS and PS-BDS PEMs exhibited a clear microphase separation structure, with the hydrophilic sulfonic acid groups located far away from the hydrophobic main chain of PS. This unique structure contributed to improved dimensional stability and oxidative stability of the PEMs. The obtained PEMs show better dimensional stability and oxidative stability. Comparing the two types of PEMs at the same temperature and ion exchange capacity (IEC), PS-BDS PEMs demonstrate better dimensional stability and lower methanol permeability compared to PS-BS PEMs. For instance, PD-BDS-4 PEMs exhibited a dimensional of stability up to 8.6% at room temperature and 30% at 85 °C. The corresponding methanol permeability was 10.29 × 10– 7 cm2/ s at 25 °C, which was significantly lower than that of Nafion112 (10.5 × 10– 7 cm2/ s) PEMs under the same condition.