Study On Coating Surface Treatment And Hydrophilic Properties Of PVC Architectural Membrane

With a series of international events such as the Shanghai World Expo, theBeijing Olympics and Guangzhou Asian Games held, PVC architectural membranematerials have got great development in our country, more and more extensiveapplication. In recent years, with increasing environmental pollution, as the materialslong-term used in the natural environment, PVC architectural membrane surface wasnot only sticky and defiled easily, but also difficult to clean, which greatly influencedits promotion and application in the field of membrane materials. In1997, Wang et alfound that water contact angle on the surface of TiO2was reduced from dozens ofdegree to zero with UV irradiation, showing a super-hydrophilic state. Follow-upstudy of many scholars believed that when the water contact angle on TiO2film <15°,droplets has a very high fluidity which made the film a self-cleaning effect.Meanwhile, anatase TiO2had good oxidation reduction to degrade organic pollutantswith UV irradiation, which further improved the self-cleaning effect of thin film.Therefore, building a hydrophilic surface membrane which used anatase TiO2for thePVC architectural membrane surface treatment by coating, is an effective way torealize the self-cleaning of the membrane.This issue was studied the surface treatment of PVC architectural membranewith excellent catalytic activity of anatase TiO2prepared by the reversemicroemulsion-hydrothermal method, then study the hydrophilic properties ofmembrane. First of all, organically combination of the microemulsion method andhydrothermal method, successful prepared excellent catalytic activity of anatase TiO2,study different (TBT):(H2O) mole ratio effect on TiO2; Secondly, the degradationbehaviors of PVC architecture membrane which was surface treatment with preparedTiO2, have been investigated under UV irradiation; Finally, Joined a isolation layer between TiO2layer and PVC membrane to preapred composite membrane and studiedits hydrophilic properties.TiO2were prepared by a reverse microemulsion-hydrothermal method adjusting(TBT):(H2O) molar ratio in the reaction system. The phase and crystal structure,surface morphology of the prepared TiO2were characterized by X-raydiffraction(XRD), transmission electron microscopy(TEM), Photolumincscencespectra (PL), etal. The results show,(1)the (TBT):(H2O) molar ratio increasedwithin a certain range, TiO2grain size got smaller first, became large later, theaverage grain size was between18nm-32nm.(2)The morphology of TiO2wasinfluenced by (TBT):(H2O) molar ratio, transformed from the irregularly shape to theregularly structure, Particle size also became uniform.(3)when (TBT):(H2O) molarratio is1:25, the photocatalytic activity of TiO2was the best, after2h of10W UVlamp irradiation, the degradation rate of methylene blue reached92.24%, higher thanthat of the commercial P25(85.42%).PVC architectural membrane was treated with TiO2, then studied thephotocatalytic degradation behavior of composite membrane. The PVC membraneand PVC membrane treated with TiO2after UV irradiation were analyzed throughgravimetric, surface morphology, chemical structure and surface elements, etc.Theresults show, the photocatalytic degradation of PVC membrane by natase TiO2wasvery obvious Under UV irradiation. Compared with the PVC membrane (K=0.0171),the degradation rate of the treated PVC composite membrane was faster(K=0.0483),TiO2accelerated the degradation of PVC membranes in conjunction with ultraviolet.SiO2as isolation layer Prepared by sol-gel method, study the hydrophilicproperties of PVC architectural membrane which was coated with SiO2and TiO2layers. The results show,(1)Amorphous SiO2coating was improved the bondingeffect between TiO2layer and the PVC membrane, prevented TiO2photocatalyticdegradation to protect PVC membrane membrane(.2)The water contact angle of PVCcomposite membrane became smaller gradually with the TiO2dosage increased. whenthe TiO2dosage was5%, The water contact angle of composite membrane reached about15°after UV irradiation(.3)With the increase of UV irradiation time, the watercontact angle of PVC composite membrane became smaller, after2h irradiation, thecontact angle dropped from42.2°to10.9°.(4)The water contact angle of PVCcomposite membrane increased with increasing dark time, after shading48h, thecontact angle was36.8°.