Versatile strategy for fabrication of polypropylene nanocomposites with inorganic network structures based on catalyzed in-situ sol–gel reaction during melt mixing

A versatile strategy based on a catalyzed in-situ sol–gel reaction in melt mixing is presented for the fabrication of polypropylene (PP) nanocomposites that equip inorganic network structures. PP nanocomposites with TiO2 network structures were obtained by melt mixing PP powder which was preliminarily impregnated with titanium alkoxide and a catalytic component. The addition of catalytic components, especially hindered amine stabilizer, was found to be effective not only for the acceleration of the in-situ sol–gel reaction but also for improved dispersion of formed inorganic nanoparticles. The obtained PP/TiO2 nanocomposites exhibited the disappearance of the terminal flow at ca. 3 wt% of the TiO2 content, indicative of the network formation. Moreover, the PP/TiO2 nanocomposite films exhibited distinct optical properties: Not only high transparency for visible lights due to the excellent dispersion of the made nanoparticles but also absorption of UV lights, where absorption edges are tunable through a quantum effect for nanosized particles.