Synthesis, Characterization and Properties of In-Situ Generated Polyimide/Silica/Polyoxometalate Hybrids via Sol-Gel Method

In this research attempt, polyimide (PI) was prepared using 4-bromobenzene-1,3-diamine dihydrochloride and trimellitic anhydride chloride. The organic-inorganic nanocomposites were developed by means of TEOS and various content of polyoxometalate (POM). The silica network was synthesized in the polyimide matrix through in-situ sol-gel technique. FTIR was used to study the formation of polyimide and sol-gel nanocomposites. The physical properties of the in-situ prepared polyimide/silica/polyoxometalate nanocomposites were compared with those of neat polymer and polyimide/silica composite. Morphology study confirmed the homogeneous dispersion of silica phase in PI bulk phase with the formation of porous network structure. The glass transition temperature of the nanocomposites was in the range of 240-275 °C, i.e. higher than the neat matrix (156 °C). The melting peaks were also increased compared with the neat polyimide. Water uptake studies exhibited significant improvement in property for hybrids with higher POM content. In summary, PI/TEOS/POM 50 nanocomposite depicted improved thermal and water absorption properties along with the well-dispersed morphology