Atomic oxygen erosion resistance of titania-polyimide hybrid films derived from titanium tetrabutoxide and polyamic acid

摘要

A series of polyimide/titania (PI/TiO_2) hybrid films have been successfully synthesized based on titanium tetrabutoxide (Ti(OEt)_4), 3,3′,4,4′-bezonphenone tetracarboxylic dianhydride (BTDA), 4,4′-oxydianiline (ODA), and 1,3-bis(aminopropyl) tetramethyldisiloxane (APrTMOS) by a sol-gel process. The atomic oxygen (AO) exposure tests were carried out using a ground-based AO effects simulation facility. The chemical structure of PI/TiO_2 films was characterized by Fourier transform-infrared (FT-IR) spectroscope before and after AO exposure. The glass transition temperature (T_g) and mechanical properties were examined by dynamic mechanical analysis (DMA) and universal mechanical testing machine, respectively. The tensile strength and elongation of the hybrid film decreased with the increase of TiO_2 content, whereas the T_g increased with the increase of TiO_2 content. The effects of TiO _2 content on the morphology and structure evolvement of PI/TiO _2 hybrid films were also investigated using field emission scanning electron microscopy (FE-SEM) and X-ray photoelectron spectroscope (XPS), respectively. The results indicated that a TiO_2-rich layer resulting from the Ti(OEt)_4 formed on the PI film after AO exposure, which decreased the mass loss rate and obviously improved the AO resistance of PI films.