Structure and properties of hybrid PP/TiO₂ nanocomposites and mesoporous TiO₂ prepared via solvent crazing

Abstract

A new method for the preparation of hybrid film polymer PP/amorphous TiO₂ nanocomposites and mesoporous crystal TiO₂ (anatase) using the crazing phenomenon has been developed. The porous structure and the sorption activity thereof were investigated. The PP/TiO₂ nanocomposite has an open-porous structure (S_sp = 5.5 m²/g; D_p = 12, 25, and >300 nm). The hydrophilic-hydrophobic balance of amorphous titanium dioxide in the PP/TiO2 nanocomposite provides significant sorption activity with respect to dye molecules upon sorption from both hydrophobic and aqueous media. The hydrophilic-hydrophobic balance of an inorganic photolytic sorbent, mesoporous crystal TiO₂ (S_sp = 140 m²/g, D_p = 24 nm), can be changed by processing in an aqueous medium. The low-temperature nitrogen sorption by the PP/TiO₂ nanocomposite was shown to be almost completely irreversible. One possible explanation for this unusual fact is associated with the formation of a thin dense film on the composite surface during the evaporation of nitrogen that prevents the removal of nitrogen from internal areas of the sample.