Preparation and characteristics of poly(amide-imide)/titania nanocomposite thin films

Poly(amide-imide)/titania (PAI/TiO2) nanocomposite has been successfully fabricated through the in situ formation of TiO2 Within a PAI matrix by sol-gel process. Poly(amide amic acid) solutions are prepared by mixing 3,3',4,4'-benzophenone tetraearboxylic dianhydride (BTDA), 2,2-bis[4-(4-aminophenoxy)phenyl]propane (p-BAPP), trimellitic anhydride chloride (TMAC) and NN-dimethyl formamide (DMF) solvent. Tetra,ethyl orthotitanate (Ti(OEt)(4)) and actylacetone (ACAC), the latter one is used as chelating agent, are then added to the poly(amide amic acid). Through the sol-gel process and imidization reaction, the PAI/TiO2, nanocomposite films are formed. In this study, the addition of TMAC to the PAI/TiO2 nanocomposite films is employed to provide the intermolecular hydrogen bonded between the PAI and PAI or titania. The TiO2 particle sizes of PAI/TiO2 (TiO2 is 8.12 wt. %) are between 40 and 90 rim by the transmission electron microscope (TEM) measurement. Based on X-ray photoelectron spectroscopic (XPS) analysis, the TiO2 content on the surface of PAI/TiO2 is higher than that of pure polyimide/titania (PI/TiO2) nanocomposite film. Thermal decomposition temperatures (T-d), at 5 wt.% loss, are above 460 degrees C of PAI/TiO2 and PI/TiO2 nanocomposite films. The dynamic mechanical analysis (DMA) of the PAI/TiO2 and PI/TiO2 nanocomposite films with higher TiO2 content possesses superior mechanical proper-ties and glass transition temperatures. (C) 2007 Elsevier B.V. All rights reserved.