Synthesis, characterization and affinity detection of sulfonated polyimides: confirmation of proton transfer in quantum theory simulations

Here, two different novel sulfonated polyimides were produced using different monomer ratios. With 2 different molecules of diamine, 3,3′,4,4′-biphenyl tetracarboxylic dianhydride and perylene-3, 4, 9, 10-tetracarboxylic dianhydride in an inert atmosphere at two-stage high temperature and the presence of sulfonic acid, sulfonated polyimides were obtained by imidization. For sulfonated polyimides, proton nuclear magnetic resonance, Fourier transform infrared, solubility tests, the affinity of polymers to solvents, ultraviolet–visible spectroscopy and thermogravimetric analysis/differential thermal analysis characterization were performed. Quantum chemical calculations of synthesized sulfonated polyimides, density functional theory and analysis of atoms in molecules theoretical calculations are presented to learn about various energy properties and to see proton transfer scripts. The thermogravimetric analysis/differential thermal analysis curve showed a second degradation stage at a temperature higher than 400 °C. Graphical abstract