Synthesis and characterization of nanocomposites based on polyimide bearing benzimidazole side groups filled with titania nanoparticles

This study reports on the fabrication and property investigation of nanocomposites based on polyimide (PI) containing benzimidazole pendant groups reinforced with titania nanoparticles (TiO2 NPs) via the in-situ thermal imidization approach. This method involves the formation of poly(amic acid) (PAA), as the precursor of PI, by polycondensation of an equimolar amount of dianhydride, pyromellitic dianhydride (PMDA), with a benzimidazole-containing diamine monomer, 5-(2-benzimidazole)-1,3-bis(4-aminophenoxy)benzene (BIDA), in dimethylacetamide (DMAc) solvent, followed by embedding various weight percentages (3, 5, and 8 wt%) of amine-functionalized titania nanoparticles (NH2-TiO2 NPs) in PAA media, and subsequent thermal imidization to be converted to PI/TiO2 nanocomposite films. The structural, morphological, and thermal properties of the obtained neat PI and its nanocomposite films were studied by various methods, such as FT-IR spectroscopy, X-ray diffraction (XRD) analysis, thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM). The data resulted from TGA analysis indicated that the incorporation of NH2-TiO2 NPs into the PI matrix show higher thermal stability when compared to the neat PI. The SEM images revealed that the dispersion of titania NPs was uniformly done in PI matrix, with a particle size of around 42 nm.