Benzimidazole based porous organic polymer: synthesis and characterization

Nowadays porous structures and materials gained much attentions due to their wide variety of applications. Benzimidazole based organic polymers are a class of porousorganic structures which made up of covalent bonds with mostly common elements such as carbon and nitrogen. Their high surface area and high porosity made them good choices for usage in the fields of catalysis and gas storage [1], [2]. Herein, synthesis of a novel benzimidazole based polymer were explained. Briefly, the tetraacid monomer of the desired structure was produced by known amount of perylene-3,4,9,10-tetracarboxylic dianhydride and calculated amount of 5- aminoisophthalic acid using the imidazole as the solvent under reflux condition for 6 hours (Scheme 1). Then the participated was filtered and washed several times with ethanol and for polymer synthesis, it was heated at 180 ˚C for 5 hours in the presence of diaminobenzidine in polyphosphoric as the solvent, finally, that the reaction was completed at 220 ˚C for 24 hours. The resulting red powder were washed with sodium bicarbonate. The structure of monomer and polymer was confirmed by Fourier transform-infrared spectroscopy, elemental analysis, X-ray diffraction, field emission scanning electron microscopy (FE-SEM), and thermogravimetric analysis. TGA of the synthesized polymer showed good thermalstability and FE-SEM images proof the good porosity of this novel structure.