Optical properties of nanocomposites based on polypropylene modified by nanoparticles of oxide compounds

The optical properties in UV, visible and near IR spectral regions for nanocomposites based on polypropylene modified by nanoparticles of oxide compounds ZrO₂, Al₂O₃, SiO₂, MgO, TiO₂, ZnO were studied. A shift of the main optical absorption edge to the short-wave region upon modification by dielectric nanoparticles (MgO, ZrO₂, and Al₂O₃) was established. The absorption edge shifts to the long-wave region upon the introduction of semiconductor nanoparticles (ZnO, TiO₂) and amorphous SiO₂ particles. In all spectra, the absorption bands at 1200, 1400, and 1720 nm characterized by overtone vibrations of CH, CH₂, and CH₃ molecular groups were recorded. OH groups make a certain contribution to the bands at 1400 and 1720 nm. The dependence of the intensity of these absorption bands on the type and concentration of nanoparticles used in the modification of polypropylene was analyzed. X-ray diffraction analysis of the studied nanocomposites was carried out, the formation of β-PP was registered upon modification by Al₂O₃ nanoparticles. Photoluminescence spectra of nanocomposites were studied. It was found that the introduction of nanoparticles (except SiO₂) does not lead to the formation of new luminescence bands in PP.