Solid-Phase Photocatalytic Degradation Of Polymer Composite Film With Nano-TiO₂ Photocatalyst

In this thesis, we reviewed the progress on the research of nano-TiO₂ semiconductor catalysts, prepared a new kind of photodegradable polymer-TiO₂ nanocomposite and study the photocatalytic degradation of them. The main results are listed as :A kind of photodegradable low-density polyethylene (LDPE)-TiO₂ nanocomposite film was prepared by blending the nanometer TiO₂ particles in LDPE matrix. Solid-phase photocatalytic degradation of the LDPE-TiO₂ nanocomposites was carried out in ambient air under ultraviolet lamp and sunlight irradiation. The properties of composite films were compared with that of the pure LDPE films by weight-loss measurement, scanning electron microscope (SEM), gel permeation chromatogram (GPC), X-ray photoelectron spectroscopy (XPS), FT-IR spectroscopy etc. methods. The results showed that the LDPE-TiO₂ nanocomposite films could be efficiently photocatalytic degraded under UV or sun light illumination. The weight loss of composite film reached 55% after 300 hours of UV-light irradiation, average molecular weight (M_w) of composite film decreased from 9.2 ×10⁴ to 5000. The weight loss of composite film reached 26% after 300 hours of sun light illumination. The photo-induced degradation of composite film is significantly higher than that of pure film. The photocatalytic degradation mechanism of the composite film is briefly discussed.A kind of composite film was prepared by blending the nanometer TiO₂ particles in HDPE matrix. The as-prepared samples were irradiated under ultraviolet lamp and sunlight. The properties of samples films were investigated by FT-IR, SEM etc. methods. The weight loss of pure film reached 17%, the composite films (TiO₂ 0.5%) reached 23 %, and the composite (TiO₂ 1%) reached 41% after 450 hours of UV-light irradiation. The results showed that the photo-induced degradation of composite film is significantly higher than that of pure film.The photodegradable poly (vinyl chloride)-grafted-TiO₂ (PVC-G-TiO₂)nanocomposite was prepared by embedding the grafted-TiO2 particles into the poly (vinyl chloride). Photocatalytic degradation of the composite films was carried out in ambient air under ultraviolet lamp. The properties of composite films were compared with that of the pure films by weight-loss measurement, UV-Vis, FT-IR, SEM etc. methods. The weight loss of pure film reached 15.1%, the composite films (TiO2 1%) reached 20.2%, and the composite (G-TiO2 1%) reached 39.6% after 432 hours of UV-light irradiation. The results showed that the photo-induced degradation of composite film is significantly higher than that of pure film.