Study On Modified And Mechanism Of Rutile Titanium Dioxide In Plastic

Nanoscale titanium dioxide, commonly known as titanium pigment, is the best one of white pigments with high whiteness, strong achromatic power, opacity and chemical stability. It widely used in paints, plastics, ceramics and paper industries. However, due to the photocatalytic activity of titanium dioxide, its plastic products produce high chemical activity of the peroxide to generate free radicals by the light of less than387.5nm wavelength, resulting in degradation of the plastic and accelerated oxidative aging of plastics. When inorganic modification of titanium dioxide is used in the plastic products, the titanium dioxide particles plays a role in separation of the plastic surface from the organic plastics, which induce a significant reduction in the photocatalytic activity of titanium dioxide, effectively improve the durability of plastic products. Hence it is important to investigate the plastic modification with rutile titanium dioxide and its mechanism of action. It was great significance to reveal the relationship between the structure-performance of modified titanium dioxide nanoparticles, high additional value and high weather resistance properties of plastic products design and development.The inorganic coated rutile titanium dioxide nanoparticles were prepared with using aluminum sulfate, sodium silicate and zirconium oxychloride as a coating agent and sodium hexametaphosphate (SHMP) as dispersant. The orthogonal design was designed to improve the composition, particle size, and the degree of dispersion of particle. Characterize the rate of gloss reduction rate, oil absorption, opacity and whiteness performance unit coated nanoparticles, evaluated the effect of inorganic coated coated rutile titanium dioxide nanoparticles modified. Using Nano-ZS, structure and properties of scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and spectroscopy (EDS) modified nanoparticles were characterized studied rutile titanium dioxide coated nanoparticles mechanism, the modified nanoparticles coated rutile titanium dioxide used in PVC plastic and study its resistance to degradation, weathering performance.The use of ZrO2, SiO2and Al2O3nanoparticles coated surface to form a coated rutile titanium dioxide nanoparticles of inorganic element, the results show that the average particle size of coated particles is about450nm with good dispersion performance. The ZrO2coated rutile titanium dioxide has the lowest loss of oil absorption value and the largest increase in whiteness, the gloss reduction rate dropped from70%to25%, the oil absorption from21.5g/100g down to17.5g/100g, the whiteness to88.5%from86.7%. The covering power of the coating was less influenced by the aluminum, silicon and zirconium modified rutile titanium dioxide.According the differences in coating capacity of ZrO2, SiO2and Al2O3three binary (ZrO2/Al2O3, ZrO2/SiO2and SiO2/Al2O3) coated rutile titanium dioxide nanoparticles was designed and prepared. The binary (ZrO2/Al2O3, ZrO2/SiO2and SiO2/Al2O3) coating has better capacity than one inorganic coating (ZrO2, SiO2and Al2O3), such as rutile titanium dioxide nanoparticles coated with ZrO2/Al2O3having the increase of whiteness from86.7%to88.9%. The binary coating layer (ZrO2/Al2O3, ZrO2/SiO2and SiO2/Al2O3) and the titanium dioxide layer combine through chemical binding, wherein inner layer of the ZrO2/Al2O3and ZrO2/SiO2coating is zirconium dioxide, and the inner layer of SiO2/Al2O3coating layer is silicon dioxide. Bilayer structure of rutile titanium dioxide coated ZrO2/Al2O3nanoparticles can enhance the whiteness, and effectively reduces the amount of ZrO2with reduced costs.To further improve performance and reduce costs of rutile titanium dioxide pitment, the design and preparation of a ternary coating containing outler layer of aluminum oxide, an intermediate layer of silica and inner zirconium dioxide were achieved by an improved sol-gel method. A new process for the synthesis of ZrO2/SiO2/Al2O3coated rutile titanium dioxide: Using the flow mode and a bath temperature of60~65℃, stirring speed of350r/min, dropping5drop/min, the pH of the package ZrO28.5to9.0, the pH of the package when SiO29.5to5.0, the pH of the Al2O3of6.0to6.5, the slurry concentration of400g/L, the amount of dispersant was0.3%, the content of ZrO20.08%, SiO2content Al2O3content of2%. The surface coating rate of ZrO2/SiO2/Al2O3coated nanoparticles is reached to98.3%with the gloss reduction rate of24%, oil absorption of17.1g/100g and the whiteness of89.2%. Compared with ZrO2, SiO2, Al2O3, ZrO2/Al2O3, ZrO2/SiO2and SiO2/Al2O3coated nanoparticles, the properties of loss of light, oil absorption and whiteness as well as dispersion performance are improved. Due to the lower costs of raw materials, it will be more effectively applied to improve the physical and chemical properties of plastic products.In addition, we respectively tested the application performance of the PVC plastics that it was added the rutile titanium dioxide R233after the ZrO2/SiO2/Al2O3inorganic coating treatment and several similar products manufactured in domestic and abroad. The results showed that added the rutile titanium dioxide R233of the PVC plastics could be uniformly dispersed in the PVC plastics, and there was no significant particle agglomeration, and the whiteness, gloss and durability of the plastic products were also able to reach the application requires of PVC plastics. In short, the application performance of home-made rutile titanium dioxide R233in the PVC plastics after the inorganic coating treatment was better than the similar domestic products, and closed to high-quality foreign rutile titanium dioxide.Finally, through the investigation of the weathering performance inorganic coated rutile titanium dioxide modified PVC plastics research, combined with TiO2photocatalytic activity of the particle surface processes generate free radicals, it showed that the inorganic coating layer has blocking effects in photochemical reaction between the plastic/titanium dioxide. The proposed mechanism of anti-aging mineral rutile titanium dioxide coated modified PVC plastics was also investigated.