Photocatalytic Self-cleaning Coating Fabric Processing Technology And Performance Research

Nano-TiO₂ is widely used in the research of self-cleaning materials because of its low cost,easy availability of raw materials and high reaction ability of decomposing organic materials.Hydrophobic and anti-aging silicone resin and PVDF were used as binders in this paper to blend with nano-TiO₂ and prepare self-cleaning coating textiles,which can decompose organic pollutants and at the same time to prevent inorganic contamination sewage because of its lower surface tension.There are large amounts of-OH on the surface of nano sized TiO₂ particles,which will cause TiO₂ seriously agglomerated in cyclohexane and can not be well dispersed.That will affect the quantum size effect of nanosized titania and leading to a decrease in photocatalytic performance.In this paper,the dispersion stability of nanometer TiO₂ in cyclohexane was improved by adding coupling agent KH-570,surfactant JFC and ethanol-cyclohexane mixed solvent.The experimental results show that the size and dispersion stability of nanosized TiO₂ are better in the mixed solvent of ethanol and cyclohexane,and the dispersion performance is the best when the volume ratio of ethanol to cyclohexane is 5:9.In the preparation of coating slurry,several organic solvents commonly used in the laboratory were used for experiments.Finally,cyclohexane was selected as the solvent of the silicone resin.The operation of the experiment and the self-cleaning performance of the coated fabric will affect by the viscosity of the coating slurry.When the content of silicone resin is 30%,Viscosity of coating is moderate,rheology is good and the fabric is not easy to be penetrated.Also,TiO₂ particles will not coated by the resin film and maintain a good photocatalytic performance.Temperature and reaction time were controlled to study the effect of additives on the curing of silicone resin,It is found that two-component silicone resin in ethanol-cyclohexane mixture will completely cured at 120℃ for 2min and addition of JFC will extends the cure time.The results show the self-cleaning performance of coating fabrics are improved with the increase of the dosage of nano-TiO₂.Self-cleaning property of PVDF coated fabric is lower than that of silicone resin coated fabric and one-component silicone resin coated fabric is higher than that two-component silicone resin coated fabric as a same dosage of resin and nano TiO₂.The self-cleaning effect of PVDF coated fabric will be a certain decline after 40 dry frictions.In order to study a accuracy method to measure the self-cleaning property of coating fabrics,colorimetric method and K/S method were respectively tested.The results show that the colorimetric method is suitable for the self-cleaning test of silicone coated fabric and K/S value method is better for PVDF coated fabric self-cleaning test.The aging resistance of the coated fabric was characterized by the contact angle,peel strength,surface topography and color change in this paper.The results show that the aging resistance of self-cleaning coatings decreases with the increase of the amount of nano-TiO₂,and the anti-aging properties of the coatings are improved by the increase of the amount of nano-TiO₂.The aging resistance is better when the dosage ratio of silicon resin and nano-TiO₂ is less than 3:1.When the ratio of silicon resin and nano-TiO₂ reached 2:1,the aging resistance is obviously decreased.One-component silicone resin and PVDF coating fabrics have a better aging resistance than the two-component silicone resin coating fabrics.