Preparation and characterization of polyimide/titania nanohybrid films

Abstract

Thermally stable polyimide/titania (PI/TiO 2 ) hybrid nanocomposite films have been successfully synthesized through the in situ formation of TiO 2 within a PI matrix via sol-gel process. Poly(amic acid) (PAA) solution is prepared from 3,5-diamino benzoyl amino phenyl-14Hdibenzo[a,j]xanthene and 4,4 0 -(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/TiO 2 . 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 TiO 2 particles are well dispersed in the PI matrix with particle size between 10 and 30 nm in diameter. POLYM. COMPOS.,