Preparation and characterization of polyimide/titania nanohybrid films

Thermally stable polyimide/titania (PI/TiO₂) hybrid nanocomposite films have been successfully synthesized through the in situ formation of TiO₂ within a PI matrix via sol‐gel process. Poly(amic acid) (PAA) solution is prepared from 3,5‐diamino benzoyl amino phenyl‐14H‐dibenzo[a,j]xanthene and 4,4′‐(hexaflouroisopropylidene)diphthalic anhydride in N‐methyl‐2‐pyrrolidinone solvent. The different amounts of tetraethyl orthotitanate and actylacetone are incorporated into PAA matrix, and then thermally imidized to form PI/TiO₂. The chelating agent, acetylacetone, was applied to reduce the gelation rate of titanium alkoxide. Thermal decomposition temperatures of nanocomposites with a 10% weight loss were in excess of 500°C, and char yields higher than 63% at 800°C in nitrogen. The chemical and morphological structures of the hybrid nanocomposites were characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, and transmission electron microscopy. The results show that the TiO₂ particles are well dispersed in the PI matrix with particle size between 10 and 30 nm in diameter. POLYM. COMPOS., 35:1486–1493, 2014. © 2013 Society of Plastics Engineers