Preparation And Property Study Of Photocatalytic Self-cleaning Fabrics With Polyvinyl Alcohol Modified TiO₂

The photocatalytic self-cleaning property of fabric is mainly realized by coating photocatalyst on the surface.Among the photocatalysts,nano titanium dioxide（TiO₂）has been widely used to achieve self-cleaning due to its high photocatalytic efficiency,excellent stability and low cost.However,there are still many problems during the actual use of nano TiO₂,which greatly reduces the market value of nano TiO₂.In this work,for the low photocatalytic efficiency in the visible light region of nano TiO₂,which apply to self-cleaning fabrics,polyvinyl alcohol（PVA）was used to modify the surface of nano TiO₂.The factors influencing the loading process on the fabric and the change of performance were explored.The main research contents and conclusions are as follows.1.Preparation and properties of self-cleaning cotton fabric with TiO₂ nanoparticles.Self-cleaning cotton fabric with bared and modified Ti O₂ nanoparticles on the surface was achieved by ultraviolet radiation and ultrasonic wave.The surface morphology,element distribution,photocatalytic activity,ultraviolet screening performance of the original and modified cotton fabric were systematically investigated with scanning electron microscope（SEM）,energy dispersive spectrometer（EDS）,the contact angle,ultraviolet-visible absorption spectrometry and photocatalytic degradation of methyl orange solution（MO）.The results show that the adhesion between cotton fabric and nanoparticles is enhanced after UV irradiation,as well as loaded stability and wash resistance.Cotton fabric with TiO₂ nanoparticles on the surface shows super-hydrophobic behavior,excellent photocatalytic activity and UV screening property.Cotton fabric with TiO₂ nanoparticles modified by PVA（PVA@TiO₂）has photocatalytic activity 3.9 times of that with the bared TiO₂ nanoparticles in the visible light region.In addition,a higher UV-visible absorption in the region of 290-400 nm wavelength can be observed for the modified TiO₂nanoparticles,thereby exhibiting a better UV screening performance.2.The influencing factors on the performance of fabric loaded PVA@TiO₂.The properties of cotton fabric and polyester fabric with different concentrations of PVA@TiO₂ nanoparticles were studied.The results show that the cotton and polyester fabric with 0.5 wt%of PVA@TiO₂ have the highest photocatalytic activity.Meanwhile,under ultraviolet light for 4 h,the catalytic degradation rate of methyl orange solution is about 85%for the cotton and 95%for the polyester fabric.Besides,the water contact angle of self-cleaning fabric was greater than 150°,showing the superhydrophobic performance.Based on the above results,different concentration of silane coupling agent（APTES）was used to improve the durability of PVA@TiO₂ on cotton fabric.The results show that the self-cleaning cotton fabric has the highest photocatalytic efficiency when impregnated in 0.5 wt%of APTES solution.Moreover,after APTES treatment,the photocatalytic durability of self-cleaning cotton fabrics is also improved.