Research On Preparation Of Photocatalytic Activity Modified Titanium Dioxide And Its Application As UV-blocking Agent

Polymer products may age after long-time exposure to UV rays and its physical and mechanical properties could deteriorate as the result. Thus, UV-blocking additives should be added into polymers to tackle this deterioration caused by UV rays. In this study, titanium dioxide?TiO2? nanoparticles were coated by silicon dioxide?SiO₂? to reduce its photocatalytic activity. It was then added in to polyvinyl butyral?PVB? and polypropylene?PP? as UV-blocking agent and its influence on anti-UV-induced-aging properties of these two kinds of polymers were then investigated.Ethylsilicate?TEOS? was used as SiO₂ source in this study. Five kinds of silicon dioxide coated titanium dioxide were prepared by controlling the useage of TEOS through its hydrolysis process. X-ray diffraction?XRD? and scanning electron microscope?SEM? were used to characterize thses samples. The photocatalytic activity of each titanium dioxide material was indicated by degradation rate of Rhodamine B at the existence of each titanium dioxide material under UV radiation. Titanium dioxide nanoparticles that possess lowest photocatalytic activity were then added into PVB as UV-blocking agent. The UV blocking performances of coated titanium dioxide and uncoated titanium dioxide were studied by testing and comparing the UV absorption curves of composites with each kind of nanoparticles in them. Fourier transform infrared spectroscopy?FTIR? and thermal gravity analysis?TG? were used to investigate the structures of these composites. Then, titanium dioxide nanoparticles that possess lowest photocatalytic activity were added into PP filaments through extruding. Its ability to enhance the anti-UV-induced-aging property of PP filaments was studied by testing and comparing the physical properties of PP samples that contain coated and uncoated titanium dioxide nanoparticles after being exposed to different strength of UV radiation for different time.XRD and SEM results show that silicon dioxide were coated on the surface of titaniumdioxide in the TEOS hydrolysis process. Rhodamine B degradation rates show that photocatalytic activities of coated titanium dioxide nanoparticles were reduced to certain extent. And the photocatalytic activity of titanium dioxide was reduced to the lowest level when 5 mL of TEOS were used in its hydrolysis process. FTIR results proved that PVB/TiO2 composites were successfully prepared. UV absorption curves show that the UV absorbing ability of PVB was dramatically improved after coated titanium dioxide was introduced.Compared with PVB/uncoated TiO2 composite, its UV absorption range showed a slight hypsochromic shift. Strain tests of PP filaments after being exposed to different strength of UV radiation show that the ability of PP filament to resist UV-induced aging were improved to different level, respectively. take one of the indexes, strength, as the indicator of its mechanical property, the strength of PP/coated TiO2 filaments were 28.07% and 35.43%higher than that of PP filaments and PP/uncoated TiO2 filaments after being exposed to high strength UV radiation for 1h, while the strength of PP/coated TiO2 filaments were 4.93% and21.97% higher than that of PP filaments and PP/uncoated TiO2 filaments after being exposed to low strength UV radiation for 72 h.