Introduction of a crystalline block as a strategy to increase swelling resistance and dimensional stability of sulfonated copolyimide

The introduction of blocks inclined to form areas of high crystallinity into the sulfonated block co-polyimide is investigated as a prospective strategy to increase swelling resistance and dimensional stability of the polymer in application to the proton exchange membranes development. The novel copolymer with the highly crystalline block was obtained and characterized by the means of static and dynamic light scattering, IR spectroscopy, thermal gravimetric analysis and differential scanning calorimetry. The structural and morphological features of the obtained copolymer were investigated with X-ray diffraction analysis and atomic force microscopy. Transport properties of the co-polyimide are evaluated in terms of pervaporation, proton conductivity measurements and dielectric spectroscopy experiments. The article aims at the evaluation of the influence of the high-crystalline block introduction on morphological, transport and physical properties of the sulfonated copolymer. The properties of the obtained crystalline sulfonated copolymer are compared to the ones of the similar amorphous polyimide. The studied crystalline copolymer showed constancy of the proton conductivity values in the broad range of temperatures (20-120 degrees C, RMSD of 0.23%) and relative humidity values.