| 초록 |
We study the synthesis and characterization of a thermally stable metal-containing in sulfonated polyimides (M-SPI) based on benzophenone tetracarboxylic dianhydride (BTDA), 4, 4-diamino 2, 2-biphenyl disulfonic acid (BDSA) and meta-phenylenediamine (mPDA). X-ray photoelectron spectroscopy (XPS) was chosen as a tool for confirmation of metal substitution in sulfonic acid group. Thermogravimetric analysis (TGA) spectrum of the M-SPI showed approximately 5% weight loss in the range of 250-350℃ and the final decomposition began at around 500℃. Wide angle X-ray diffraction (WAXD) spectra of M-SPI show no crystalline behavior, indicating an amorphous structure of the polymer. The water sorption of the M-SPI was investigated at 25℃ and 60% RH. The diffusion coefficient and water uptake were estimated to be 2.68×10-7 cm2/s and 2.33 wt% for Na-SPI 1091 and 3.79×10-7cm2/s and 4.03 wt% for Na-SPI 1082. The gas transport properties of O2 and N2 for M-SPI have been investigated as a function of the substituted metal ion in sulfonic acid group. The O2 permeability slightly increased in the order of Li-SPI〈 Na-SPI〈 K-SPI. It might be explained that the d-spacing between polymer interchains increased by the presence of metal ions with different ion radii. Metal-containing sulfonic acid groups on the phenylene also inhibited the close packing of the polymer chains. |
