Microstructure and properties of novel ReO₂ /polyimide nanocomposite films

A series of Rhenium (VII, Re⁷⁺) compound-doped polyimide (PI) nanohybrid films had been successfully fabricated from methyltrioxorhenium (MTO) and polyamic acid (PAA) via the solution direct-dispersing method, followed by a stepwise thermal imidization process. X-ray photoelectron spectroscopy (XPS) confirmed that MTO had decomposed into Re (IV) oxidation state (ReO₂). Field emission scanning electron microscopy (FE-SEM) showed that for the differrent hybrid films, the ReO₂ nanoparticles which formed by MTO decomposing well dispersed in polyimide matrix with a size of 40–60 nm. Thermal analysis indicated that the introduction of MTO decreased the thermal stability and the glass transition temperature (T_g) because of the unstable MTO. DMTA and static tensile measurements showed that the storage modulus and the elongation at break of nanocomposite films had a maximum value when the 1% of MTO was doped in PI, while the tensile strength decreased with increasing MTO content on the whole.